MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE

MARICOPA COUNTY NONATTAINMENT AREA

APPENDICES

VOLUME TWO

MAY 2012
MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE

MARICOPA COUNTY NONATTAINMENT AREA

APPENDICES

MAY 2012
MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE

 MARICOPA COUNTY NONATTAINMENT AREA

APPENDICES

APPENDIX A

Exhibit 1: 2008 PM-10 Periodic Emissions Inventory for the Maricopa County,

Arizona, Nonattainment Area. Maricopa County Air Quality Department. 

Revised June 2011.

APPENDIX B

Exhibit 1: Technical Document in Support of the MAG 2012 Five Percent Plan for

PM-10 for the Maricopa County Nonattainment Area. Maricopa

Association of Governments.

Exhibit 2: Calculation of Benefits from PM-10 Certified Street Sweepers Purchased

with CMAQ Funds in 2001-2009.

APPENDIX C

Exhibit 1: Arizona Revised Statutes Listed in Table 4-1.

Exhibit 2: Maricopa County Resolution to Evaluate Measures in the MAG 2012 Five

Percent Plan for PM-10 for the Maricopa County Nonattainment Area.

Exhibit 3: Arizona Department of Environmental Quality Dust Action General Permit.

Exhibit 4: Arizona Department of Environmental Quality Commitment to Revise the

MAG 2012 Five Percent Plan for PM-10 for the Maricopa County

Nonattainment Area if Necessary for the Emerging and Voluntary

Measure.

APPENDIX D

Exhibit 1: Agricultural Best Management Practices Program.

APPENDIX E

Exhibit 1: Public Hearing Process Documentation.

Exhibit 2: Certification of Adoption.
APPENDIX B
APPENDIX B

EXHIBIT 1:

Technical Document in Support of the MAG 2012 Five

Percent Plan for PM-10 for the Maricopa County

Nonattainment Area. Maricopa Association of Governments
TECHNICAL DOCUMENT

IN SUPPORT OF THE

MAG 2012 FIVE PERCENT PLAN FOR PM-10

FOR THE MARICOPA COUNTY NONATTAINMENT AREA

May 2012

Maricopa Association of Governments

302 North 1st Avenue, Suite 300

Phoenix, Arizona 85003
TABLE OF CONTENTS

CHAPTER PAGE

I INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I-1

II BASE CASE PM-10 EMISSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

POINT SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

AREA SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-1

NONROAD MOBILE SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-7

ONROAD MOBILE SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-10

SUMMARY OF BASE CASE PM-10 EMISSIONS . . . . . . . . . . . . . . . . . . . . . II-17

III EVALUATION OF RULE EFFECTIVENESS . . . . . . . . . . . . . . . . . . . . . . . . . III-1

IV EVALUATION OF CONTINGENCY PROJECTS . . . . . . . . . . . . . . . . . . . . . IV-1

PM-10 CERTIFIED STREET SWEEPING . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-2

PAVING AND STABILIZING UNPAVED ROADS AND ALLEYS . . . . . . . . . . IV-7

PAVING AND STABILIZING UNPAVED SHOULDERS . . . . . . . . . . . . . . . . IV-12

REDUCED SPEED LIMITS ON UNPAVED ROADS AND ALLEYS . . . . . . IV-12

OVERLAYS WITH RUBBERIZED ASPHALT . . . . . . . . . . . . . . . . . . . . . . . IV-16

DEMONSTRATION THAT THE PM-10 REDUCTION

PROJECTS IMPLEMENTED IN 2008-2011 MEET

CONTINGENCY REQUIREMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-16

PM-10 REDUCTIONS DUE TO ALL MEASURES AND

PROJECTS IN THE FIVE PERCENT PLAN . . . . . . . . . . . . . . . . . . . . . . . . IV-19

V ATTAINMENT MODELING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-1

CONCEPTUAL MODEL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-2

i
TABLE OF CONTENTS (Continued)

CHAPTER PAGE

TEMPORARY MONITOR INSIGHTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-7

SOURCE WEIGHTING ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-21

BACKGROUND CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-28

DESIGN DAY SELECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-41

MODELING DOMAINS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-53

INVENTORY DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-62

CONTROL MEASURE ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-79

DEMONSTRATION OF ATTAINMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-80

ii
LIST OF TABLES

TABLE PAGE

Table II-1 Growth Factor for the PM-10 Nonattainment Area . . . . . . . . . . . . . . . . II-2

Table II-2 2007-2012 Base Case Emissions in the PM-10

Nonattainment Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-3

Table II-3 Growth Factors for Aircraft and Ground Supoort

Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-8

Table II-4 Growth Factors for Other Nonroad Mobile Sources . . . . . . . . . . . . . . . II-9

Table II-5 2007-2012 PM-10 Emissions from Exhaust, Tire Wear

and Break Wear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-12

Table II-6 PM-10 Emission Rates from PM-10 Certified and

Conventional Sweepers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II-14

Table II-7 Usage Factors for PM-10 Certified Street Sweepers . . . . . . . . . . . . . II-15

Table III-1 Impact of Increased Rule Effectiveness on 2008-2012

PM-10 Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III-2

Table III-2 2008-2012 PM-10 Emissions with Increased Rule

Effectiveness ............................................ III-4

Table III-3 PM-10 Emission Reductions and Five Percent 

Reduction Requirements ................................... III-5

Table IV-1 2008-2012 PM-10 Emission Reductions for Contingency

Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-3

Table IV-2 PM-10 Emission Reductions for ADOT Sweeping . . . . . . . . . . . . . . . . IV-5

Table IV-3 PM-10 Reductions for Paving and Stabilizing Unpaved

Roads/Alleys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-9

Table IV-4 PM-10 Reductions for Paving and Stabilizing Unpaved

Shoulders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-13

Table IV-5 PM-10 Reductions for Reduced Speed Limits on Unpaved

Roads and Alleys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-17

iii
LIST OF TABLES (Continued)

TABLE PAGE

Table IV-6 PM-10 Reductions for ADOT Overlays with Rubberized

Asphalt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-18

Table IV-7 2008-2012 PM-10 Emissions with All Plan Measures and

Contingency Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-20

Table V-1 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds Exceeded

12 mph (0-175 degrees) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-12

Table V-2 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds Exceeded

12 mph (180-360 degrees) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-13

Table V-3 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds are Between

6-12 mph (0-175 degrees) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-14

Table V-4 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds are Between

6-12 mph (180-360 degrees) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-15

Table V-5 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds are Greater

than 2 mph, but do not Exceed 6 mph (0-175 degrees) . . . . . . . . . . V-16

Table V-6 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at West 43rd Avenue/Broadway

and West 43rd Avenue Monitors when Winds are Greater

than 2 mph, but do not Exceed 6 mph (180-360 degrees) . . . . . . . . V-17

Table V-7 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at 51st Avenue and 

West 43rd Avenue/Broadway (lagged 5-minutes)

Monitors when Winds Exceeded 12 mph (180-355 degrees) . . . . . . V-18

iv
LIST OF TABLES (Continued)

TABLE PAGE

Table V-8 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at 67th Avenue and 

51st Avenue (lagged 10-minutes) Monitors when 

Winds Exceeded 12 mph (180-355 degrees) . . . . . . . . . . . . . . . . . . V-19

Table V-9 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at 115th Avenue and 

67th Avenue (lagged 25-minutes) Monitors when 

Winds Exceeded 12 mph (180-355 degrees) . . . . . . . . . . . . . . . . . . V-20

Table V-10 Particle Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-22

Table V-11 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at Arlington and Buckeye

Monitors when are Greater than 12 mph . . . . . . . . . . . . . . . . . . . . . . V-32

Table V-12 Data Used to Calculate High Wind PM-10 Background

Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-35

Table V-13 Angular Comparison of Matched Five-Minute PM-10

Concentrations Collected at Arlington and Buckeye

Monitors when are Less than 12 mph . . . . . . . . . . . . . . . . . . . . . . . . V-38

Table V-14 Data Used to Calculate Low Wind PM-10 Background

Concentrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-40

Table V-15 24-Hour Average NAAQS Exceedance Dates, Measured

Concentrations and Associated Meteorological

Conditions in 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-42

Table V-16 Hourly PM-10 Concentrations and Wind Speeds at the

Higley Monitor at 8:00 - 11:00 PM on August 23, 2007 . . . . . . . . . . . V-44

Table V-17 Hourly PM-10 Concentrations and Wind Speeds at the

South Phoenix Monitor on August 13, 2007 . . . . . . . . . . . . . . . . . . . V-46

Table V-18 Comparison of PM-10 Concentrations During 2007

Exceedance Days Under Different Wind Regimes . . . . . . . . . . . . . . V-47

Table V-19 Peak Hourly PM-10 Concentrations and Wind Speeds

in the Maricopa Nonattainment Area During 2007 . . . . . . . . . . . . . . V-47

v
LIST OF TABLES (Continued)

TABLE PAGE

Table V-20 Breakout of High and Low Wind Hours on Modeled

Design Days at Each Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-54

Table V-21 Dust Plume Arc as a Function of Wind Speed . . . . . . . . . . . . . . . . . V-56

Table V-22 Results of Aerial Photography Analysis of Percentage of

Bare Soil on Land Uses with both Bare and Covered 

Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-64

Table V-23 Windblown PM-10 Emission Factors (tons/acre-five-minute)

by 10-Meter Wind Speed Bin and Soil Stabilization . . . . . . . . . . . . . V-64

Table V-24 Calendar Year Rule Effectiveness Rates as Surrogates

for Soil Disturbance Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-65

Table V-25 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for May 4, 2007 Design Day at the

West 43rd Avenue Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-68

Table V-26 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

Central Phoenix Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-69

Table V-27 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

Durango Complex Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-70

Table V-28 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

Greenwood Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-71

Table V-29 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

Higly Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-72

Table V-30 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

West Phoenix Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-73

vi
LIST OF TABLES (Continued)

TABLE PAGE

Table V-31 Base Case 2007 and Controlled 2012 High Wind PM-10 

Emissions Inventories for June 6, 2007 Design Day at the

West 43rd Avenue Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-74

Table V-32 Annual Low Wind PM-10 Emission Inventory Allocated

by Land Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-76

Table V-33 Annual Low Wind PM-10 Tons per Acre Emission Rates

in the Nonattainment Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-77

Table V-34 Annual Base Case 2007 and Controlled 2012 Low Wind

PM-10 Emissions Inventories for the Salt River Area 

Low Wind Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-77

Table V-35 Annual Base Case 2007 and Controlled 2012 Low Wind

PM-10 Emissions Inventories for the Central City Low

Wind Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-78

Table V-36 Annual Base Case 2007 and Controlled 2012 Low Wind

PM-10 Emissions Inventories for the Higley Low Wind 

Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-78

Table V-37 2012 Attainment Demonstration High Wind Design Day

(May 4, 2007) at the West 43rd Avenue Monitor . . . . . . . . . . . . . . . . V-81

Table V-38 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the Central Phoenix Monitor . . . . . . . . . . . . . . . . . V-82

Table V-39 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the Durango Complex Monitor . . . . . . . . . . . . . . . V-83

Table V-40 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the Greenwood Monitor . . . . . . . . . . . . . . . . . . . . . V-84

Table V-41 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the Higley Monitor . . . . . . . . . . . . . . . . . . . . . . . . . V-85

Table V-42 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the State Super Site Monitor . . . . . . . . . . . . . . . . . V-86

vii
LIST OF TABLES (Continued)

TABLE PAGE

Table V-43 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the West Phoenix Monitor . . . . . . . . . . . . . . . . . . . V-87

Table V-44 2012 Attainment Demonstration High Wind Design Day

(June 6, 2007) at the West 43rd Avenue Monitor . . . . . . . . . . . . . . . . V-88

viii
LIST OF FIGURES

FIGURE PAGE

Figure III-1 Demonstration of Reasonable Further Progress ................. III-7

Figure IV-1 Map of Highways in the PM-10 Nonattainment Area

Swept by ADOT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-4

Figure IV-2 Map of Road and Alley Paving Projects Completed in

January 2008 - September 2011 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV-8

Figure V-1 Location of Temporary and Long-Term PM-10

Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-7

Figure V-2 Relationship Between PM-10 Concentration and Source

Distance at Different Wind Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . V-23

Figure V-3 Relationship Between PM-10 Concentration and Source

Distance Increments at 12 mph Wind Speed . . . . . . . . . . . . . . . . . . V-25

Figure V-4 Relationship Between PM-10 Concentration and 

Increasing Source Distances at 12 mph Wind Speed . . . . . . . . . . . . V-26

Figure V-5 Location of Temporary and Long-Term PM-10

Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-28

Figure V-6 Comparison of WD, WSPD and PM-10 Observations

at Arlington, Buckeye and West 43rd Monitoring Sites

During 4/28/2010 - 4/29/2010 High Wind Events . . . . . . . . . . . . . . . V-30

Figure V-7 Comparison of WD, WSPD and PM-10 Observations

at Arlington, Buckeye and West 43rd Monitoring Sites

During 5/22/2010 - 5/23/2010 High Wind Events . . . . . . . . . . . . . . . V-31

Figure V-8 Close-In View of Arlington Temporary Monitor and

Angular Segments Included and Excluded from the

Background Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-36

Figure V-9 Hourly Average Wind Speed and PM-10 Concentration

at West 43rd Avenue Monitor on June 6, 2007 . . . . . . . . . . . . . . . . V-49

Figure V-10 Hourly Average Wind Speed and PM-10 Concentration

at Higley Monitor on June 6, 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . V-50

ix
LIST OF FIGURES (Continued)

FIGURE PAGE

Figure V-11 Hourly Average Wind Speed and PM-10 Concentration

at West 43rd Avenue Monitor on May 4, 2007 . . . . . . . . . . . . . . . . . V-51

Figure V-12 Example High Wind Trajectory and Resulting High

Wind Domain (Hour 15 from West 43rd Avenue Monitor

on June 6, 2007) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-58

Figure V-13 Salt River Area Low Wind Domain . . . . . . . . . . . . . . . . . . . . . . . . . . V-59

Figure V-14 Higley Low Wind Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-60

Figure V-15 Central City Low Wind Domain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V-61

Figure V-16 Land Uses Capable of Producing Windblown Dust

Within the Hour 15, West 43rd Avenue Monitor,

High Wind Domain (June 6, 2007) . . . . . . . . . . . . . . . . . . . . . . . . . . V-63

x
I. INTRODUCTION

The Technical Document in Support of the MAG 2012 Five Percent Plan for PM-10 for the

Maricopa County Nonattainment Area (TSD) describes the base case emission inventories,

quantification of measures used to meet the five percent and contingency requirements,

and the modeling that demonstrates attainment in the PM-10 nonattainment area. 

The U.S. Environmental Protection Agency (EPA) published a final notice on June 6, 2007

that the Maricopa County PM-10 Nonattainment Area had failed to attain the 24-hour PM10 standard by December 31, 2006. Section 189(d) of the Clean Air Act requires Serious

nonattainment areas that do not meet the applicable attainment date to prepare a plan that

reduces PM-10 emissions by at least five percent per year until the standard is attained at

all monitors. The Clean Air Act specifies that the plan must be based on the most recent

emissions inventory for the area, meet contingency requirements, and include a modeling

demonstration of attainment.

The 2008 PM-10 Periodic Emission Inventory for the Maricopa County, Arizona,

Nonattainment Area, revised in June 2011 (PEI), is the most recent emissions inventory

for the area (Appendix A, Exhibit 1). This inventory has been used as the basis for the five

percent and contingency reductions and the attainment modeling required by the Clean Air

Act. Chapter II of the TSD describes the development of the 2007-2012 base case

emission inventories that were derived from the 2008 PEI. 

Chapter III discusses the methods used to quantify rule effectiveness for Maricopa County

Rules 310, 310.01 and 316. As described in the Plan, the increases in rule effectiveness

between 2007 and 2012 are sufficient to meet the annual five percent reduction

requirements (Chapter Five) and demonstrate modeled attainment (Chapter Six). 

Chapter IV describes the technical assumptions used to meet contingency requirements

of the Clean Air Act. The requirement is met by quantifying the PM-10 emission reductions

due to numerous projects completed in the nonattainment area in 2008-2011. These

projects include PM-10 certified street sweeping; paving and stabilizing unpaved roads,

alleys and shoulders; reducing speed limits on unpaved roads and alleys, and overlaying

payment with rubberized asphalt. As discussed in Chapter Six of the Plan, cumulatively,

these reductions are sufficient to meet EPA’s contingency guideline of one year of

reasonable further progress (RFP). 

Chapter V documents the technical assumptions underlying the rollback modeling used to

demonstrate attainment by 2012. As discussed in Chapter Six of the Plan, the modeling

concludes that the PM-10 standard will be attained on high wind days at the West 43rd

Avenue monitor and throughout the PM-10 nonattainment area by December 31, 2012. 

I - 1
II. BASE CASE PM-10 EMISSIONS

Section 189(d) of the Clean Air Act requires that the plan provide an annual reduction in

PM-10 emissions of not less than five percent of the emissions in the most recent inventory

prepared for the area. The MAG 2012 Five Percent Plan for PM-10 provides reductions

of five percent per year from the 2007 base year until the attainment year of 2012. This

chapter describes the development of the base case emissions for 2007 through 2012. 

“Base case” emissions do not include reductions due to measures quantified in either the

MAG 2007 Five Percent Plan or the MAG 2012 Five Percent Plan. 

In June 2011, the Maricopa County Air Quality Department finalized the latest version of

the 2008 PM-10 Periodic Emissions Inventory (PEI). The 2007-2012 base case emissions

are derived from the 2008 PEI (Appendix A, Exhibit 1). Growth factors have been applied

to the 2008 PEI emissions to estimate 2007 and 2009-2012 base case emissions. For

most source categories, the growth factors are derived from projections for the PhoenixMesa metropolitan area released in August 2011 by Marshall Vest of the University of

Arizona, Economic and Business Research Center. These projections are based on the

2010 U.S. Census and the latest economic forecasts for the Phoenix metropolitan area. 

Since the economic outlook for the United States and Arizona remains extremely volatile,

the actual population and employment levels in 2011 and 2012 may differ from the

projections. However, the University of Arizona growth factors represent the most reliable 

data currently available. Table II-1 summarizes the annual projection factors, relative to

2008, for population, construction employment and manufacturing employment. 

The remainder of this chapter documents the derivation of the 2007-2012 base case

emissions in Table II-2. The discussion is organized by major source category, i.e., point,

area, nonroad mobile and onroad mobile. The order of the subcategories is consistent with

the source category sequence in Table II-2. All tonnage estimates referred to below

represent annual PM-10 emissions in the Maricopa County PM-10 nonattainment area.

POINT SOURCES

Point sources of PM-10 emissions are those permitted sources that emit more than five

tons per year of PM-10. The 2008 PEI estimate of 149.84 tons from point sources is backcast to 2007 and projected to 2009-2012 using the manufacturing employment growth

factors shown in Table II-1.

AREA SOURCES

Area sources of PM-10 emissions include fuel combustion, wildfires, agriculture,

construction, travel on unpaved parking lots, off-road recreational vehicles, leaf blowers,

windblown dust, and industrial processes that are not large enough to qualify as point

sources. The derivation of 2007-2012 base case emissions for each of these area sources

is discussed below. As noted previously, the source subcategories are organized in the

same sequence as Table II-2.

II - 1
 Table II-1 

Growth Factors for the PM-10 Nonattainment Area

Factors Relative to 2008

2007 2008 2009 2010 2011 201

 Population 0.981 1.000 1.005 1.008 1.012 1.02 Construction Employment 1.216 1.000 0.689 0.588 0.569 0.57 Manufacturing Employment 1.058 1.000 0.886 0.849 0.852 0.89

Note: The growth factors above are based on the 3rd Quarter 2011 baseline projections for the Phoenixarea published by Marshall Vest, Economic and Business Research Center, University of Arizona. 

metropolitan area includes all of Maricopa and Pinal Counties. The table below shows the Marshall Ves

and percentage changes relative to each previous year, beginning in 2009. For 2007, the percent chan

to 2008, since 2008 is the year for the latest PM-10 emissions inventory (Appendix A, Exhibit 1).

Year Population %

Construction

Employment %

Manufacturing

Employment %

2007 4,087,390 -1.9% 169,392 21.6% 137,242 5.82008 4,167,019 139,358 129,6832009 4,186,131 0.5% 96,008 -31.1% 114,883 -11.42010 4,200,427 0.3% 82,021 -14.6% 110,047 -4.22011 4,215,500 0.4% 79,283 -3.3% 110,444 0.42012 4,251,802 0.9% 80,580 1.6% 116,448 5.4

II - 2
 Table II-2 

2007-2012 Base Case Emissions in the PM-10 Nonattainment Area

tons/year

Source Category 2007 2008 2009 2010 2011 2012POINT 158.53 149.84 132.76 127.18 127.69 134.59AREAFuel combustion 1,275.94 1,300.65 1,307.15 1,311.07 1,316.32 1,328.17Commercial cooking 974.17 993.04 998.01 1,001.00 1,005.00 1,014.05Construction (includes windblown dust) 16,671.97 13,811.01 9,691.77 8,359.38 8,102.20 8,222.78Tilling, harvesting and cotton ginning 936.27 893.20 893.20 893.20 893.20 893.20Travel on unpaved farm roads 768.69 731.03 731.03 731.03 731.03 731.03Livestock 260.95 260.95 260.95 260.95 260.95 260.95Travel on unpaved parking lots 2,375.50 2,421.51 2,433.62 2,440.92 2,450.68 2,472.74Offroad recreational vehicles 2,138.74 2,180.16 2,191.06 2,197.63 2,206.42 2,226.28Leaf blowers 877.98 894.98 899.45 902.15 905.76 913.91Windblown agriculture 447.85 447.85 447.85 447.85 447.85 447.85Other windblown sources 5,430.01 5,430.01 5,430.01 5,430.01 5,430.01 5,430.01Fires 496.71 496.71 496.71 496.71 496.71 496.71Mining/quarrying (includes windblown dust) 752.18 721.38 660.84 641.08 642.89 667.32Travel on industrial paved/unpaved roads 770.71 728.46 645.41 618.31 620.78 654.30Other industrial sources 1,032.62 976.01 864.74 828.43 831.74 876.65NONROADAircraft 193.54 183.80 151.52 141.54 143.44 145.50Airport ground support equipment 28.64 26.99 23.32 20.94 20.11 19.90Locomotives 34.16 34.16 34.16 34.16 34.16 34.16Other nonroad equipment 1,709.76 1,682.91 1,660.64 1,640.88 1,595.22 1,513.25ONROADExhaust 2,943.36 2,835.65 2,647.20 2,371.05 1,843.23 1,407.06Tire wear 245.80 255.82 256.50 257.23 257.94 261.41Brake wear 727.66 758.17 767.49 770.58 772.79 787.25Paved roads 7,749.01 8,154.57 8,213.92 8,289.47 8,322.90 8,421.72Unpaved roads and alleys 10,217.66 10,312.22 10,284.04 10,284.04 10,284.04 10,312.22TOTALS 59,218.38 56,681.08 52,123.36 50,496.80 49,743.06 49,673.01

II - 3
Fuel Combustion

This category includes residential, commercial and industrial gas, wood and oil burning. 

The 2008 PEI estimate of 1,300.65 tons from fuel combustion is back-cast to 2007 and

projected to 2009-2012 using the population growth factors shown in Table II-1.

Commercial Cooking

This category includes restaurant cooking with five types of equipment: chain-driven

charbroilers, under-fired charbroilers, deep-fat fryers, flat griddles and clamshell griddles.

The 2008 PEI estimate of 993.04 tons for commercial cooking is back-cast to 2007 and

projected to 2009-2012 using the population growth factors in Table II-1.

Construction

The 2008 PEI estimates of annual PM-10 emissions from construction are 1,692.38 tons

for residential construction, 4,057.29 tons for commercial construction, 2,051.78 tons for

road construction, and 162.41 tons for other land clearing. The other land clearing

category includes site preparation, weed control and trenching. 

Rule Effectiveness (RE) rates for earth-moving activities permitted under Maricopa County

Rule 310 have been calculated by the Maricopa County Air Quality Department using

actual earthmoving inspection data for the years 2007-2010. The methodology used in

calculating the RE rates was developed in consultation with the Environmental Protection

Agency. The RE rate for Rule 310 in 2007 was 76 percent and in 2008, 90 percent. This

major increase in rule effectiveness is attributable to strengthened and increased

enforcement of Rule 310. 

The 2008 PEI estimate of 7,963.86 tons for construction emissions was adjusted to account

for the decrease in RE from 90 percent to 76 percent, resulting in non-windblown

construction emissions of 13,245.15 tons. These 2008 emissions were back-cast to 2007

and projected to 2009-2012 using the construction employment growth factors in Table II-1. 

The addition of the windblown construction emissions of 565.86 tons, discussed in the

Windblown Dust section below, produced the total 2008 base case construction emissions

of 13,811.01 tons shown in Table II-2. 

Agriculture

The 2008 PEI estimates of PM-10 emissions from agriculture include tilling and harvesting

(888.34 tons), travel on unpaved farm roads (731.03 tons), cotton ginning (4.86 tons), and

livestock (260.95 tons). The factor to back-cast agricultural activity from 2008 to 2007 was

derived from the trends in Arizona Agricultural Statistics Bulletins for Maricopa County

between 2000 and 2004. (Complete data on crop acreage in Maricopa County was not

available after 2004). Based on these trends, tilling and harvesting acreage was expected

to decline by 4.6 percent between 2007 and 2008. This 4.6 percent decline between 2007

II - 4
and 2008 translates into a 4.8 percent increase between 2008 and 2007. The agricultural

emissions for 2009-2012 are held constant at 2008 PEI levels, due to reductions in

agricultural product demand associated with the economic recession that began in 2008.

Travel on Unpaved Parking Lots

The 2008 PEI estimate of 2,365.07 tons of PM-10 emissions generated by vehicles

traveling on unpaved parking lots was back-cast to 2007 and projected to 2009-2012 based

on the population growth factors in Table II-1.

Off-Road Recreational Vehicles

The PEI estimate of 2,014.17 tons of PM-10 generated off-road recreational vehicles was

back-cast to 2007 and projected to 2009-2012 based on the population growth factors in

Table II-1.

Leaf Blower Fugitive Dust

The PEI estimate of 894.98 tons of PM-10 produced by leaf blowers was back-cast to 2007

and projected to 2009-2012 based on the population growth factors in Table II-1.

Windblown Dust

The 2008 PEI estimate for windblown dust from all sources is 4,814.80 tons. This includes

windblown dust from construction (391.00 tons), mining/quarrying (131.57 tons), agriculture

(354.24 tons) and vacant land and other sources (3,937.99 tons) including open space,

landfills and test tracks. Details concerning the methodology and data used to estimate the

2008 windblown dust emissions are provided in Appendix 4 of the 2008 PEI. 

To obtain base case emissions for windblown sources, the rule effectiveness (RE) rates

for each category in 2008 have been adjusted to the appropriate 2007 RE. Between 2007

and 2008, RE rates for construction increased from 76 to 90 percent; mining/quarrying

increased from 40 to 65 percent; and vacant land increased from 85 to 95 percent. 

Adjusting the 2008 PEI emissions to these 2007 RE rates results in 565.86 tons for

windblown construction, 190.36 tons for mining/quarrying, 5,430.01 tons for vacant land

and other sources, and 447.85 tons for agriculture. In the case of windblown agricultural,

the non-cropland portions of windblown agriculture emissions are assumed to have the

same RE rates as vacant lands in the 2008 PEI and are thus affected by changes in RE

rates from 2007 to 2008. The cropland portion of windblown agricultural emissions are

calculated using a separate methodology in the 2008 PEI and are held constant between

2008 and 2007. 

The 2007 base case emissions for all windblown categories are held constant from 2008

through 2012. Windblown construction and mining/quarrying emissions are added to the

corresponding non-windblown categories in Table II-1, while windblown agriculture and

II - 5
other windblown sources are shown as separate categories.

Fires

This category include wildfires, prescribed fires, structure fires and vehicle fires. The 2008

PEI estimate for this category is 469.03 tons. This 2008 estimate is held constant in 2007

and 2009-2012 because the biggest contributor to this category is wildfires (90 percent),

which are not possible to predict or control.

Non-Metallic Mineral Processing and Mining/Quarrying

Non-metallic mineral processing includes concrete batch plants, ceramic clay and tile

manufacturing, brick manufacturing and gypsum mining. The Mining/Quarrying category

includes sand and gravel operations and other types of mining. The 2008 PEI estimates 

are 187.73 tons for non-metallic mineral processing and 156.60 tons for mining/quarrying.

Rule Effectiveness (RE) rates for non-metallic mineral processing and sand and gravel

operations permitted under Maricopa County Rule 316 have been calculated by the

Maricopa County Air Quality Department using actual inspection data for the years 2007-

2010. The methodology used in calculating the RE rates was developed in consultation

with the Environmental Protection Agency. The RE rate for Rule 316 was 40 percent in

2007 and 65 percent in 2008. This major increase in rule effectiveness is attributable to

strengthened enforcement and increased compliance with Rule 316.

The 2008 PEI emissions for non-metallic mineral processing and mining/quarrying were

adjusted to account for the decrease in RE from 65 percent to 40 percent, resulting in total

non-windblown emissions of 531.01 tons. These 2008 emissions were back-cast to 2007

and projected to 2009-2012 based on the manufacturing employment growth factors in

Table II-1. The addition of the windblown mining/quarrying emissions of 190.36 tons,

discussed in the Windblown Dust section above, produced base case non-metallic mineral

processing and mining/quarrying emissions of 721.38 tons. These two categories are

combined and denoted as “mining/quarrying” in Table II-2.

Travel on Industrial Roads

Travel on Industrial Roads includes emissions from motor vehicles traveling on paved and

unpaved roads within the boundaries of a facility that is permitted by Maricopa County. The

2008 PEI emissions for this category are 472.36 tons. The 2008 PEI estimate was

adjusted to account for the decrease in rule effectiveness for Rule 316, as discussed in the

previous section. Decreasing the RE from 65 percent to 40 percent produced 2008 base

case emissions for travel on industrial roads of 728.46 tons. The base case 2008

emissions were back-cast to 2007 and projected to 2009-2012 based on the manufacturing

employment growth factors in Table II-1.

II - 6
Other Industrial Sources

This category includes manufacturing and other industrial activities that do not individually

produce enough emissions to qualify as point sources and are not addressed in any of the

other Area Source categories above. The 2008 PEI estimate of PM-10 emitted by these

other industrial sources is 976.01 tons. The other industrial source emissions were backcast to 2007 and projected to 2009-2012 using the manufacturing employment growth

factors in Table II-1. 

NONROAD MOBILE SOURCES

Nonroad mobile sources are those that move or are movable within a 12-month period and

are not licensed or certified as highway vehicles. This category includes exhaust emissions

from equipment used in agriculture, construction, mining, landscaping, commerce, industry

and recreation. The category also includes aircraft, airport equipment and locomotives.

The growth factors vary by equipment type.

The 2008 PEI estimate of PM-10 emissions from all nonroad mobile sources is 1,927.89

tons per year for the PM-10 nonattainment area. The major source categories and

emission estimates for 2007-2012 are discussed in the sections that follow.

Aircraft and Airport Ground Support Equipment

The 2008 PEI estimate of PM-10 emissions from aircraft is 183.80 tons, while airport

ground support equipment (GSE) emissions, which include emissions from auxiliary power

units (APUs), are 26.99 tons. These 2008 estimates were back-cast to 2007 and grown

to 2009-2012 based on the growth factors shown in Table II-3. The aircraft growth factors

were derived from estimates of landings and takeoffs (LTO) obtained from the Federal

Aviation Administration (FAA). The growth factors for GSE were estimated using the FAA

Emissions Dispersion Modeling System (EDMS), version 5.1.3. 

Locomotive Emissions

The 2008 PEI PM-10 emissions estimate of 34.16 tons for locomotives was derived from

surveys of the three railroad companies that have operations in Maricopa County

(Burlington Northern Santa Fe, Union Pacific and Amtrak). The 2008 locomotive emissions

are held constant in 2007-2012.

Other Nonroad Mobile Source Equipment

The 2008 PEI estimate for other nonroad sources besides aircraft, airport GSE and

locomotives is 1,682.94 tons. MAG ran the EPA NONROAD2008 model to estimate 2007-

2012 PM-10 emissions by source type using the same inputs assumed in the 2008 PEI

(Appendix A, Exhibit 1). The 2007-2012 emissions by source type for other nonroad mobile

source equipment and the corresponding growth factors are shown in Table II-4. The

II - 7
 Table II-3 

Growth Factors for Aircraft and Ground Support Equipment

PM-10 Annual Emissions from Aviation Sources in PM-10 NAA

(metric tons) Growth Factors Relati

Source Type 2007 1 2008 2009 2 2010 2011 2012 2007 2008 2009 2010 

Aircraft 3 254.80 241.98 199.49 186.34 188.84 191.56 1.053 1.000 0.824 0.770 

GSE+APUs4 30.74 28.97 25.03 22.48 21.59 21.36 1.061 1.000 0.864 0.776 

Total 285.54 270.95 224.52 208.82 210.43 212.92 1.054 1.000 0.829 0.77

1Landings and takeoffs (LTOs) for the years 2007, 2008, and 2009 are extracted from the FAA website 

(http://aspm.faa.gov/opsnet/sys/Airport.asp); LTOs for years 2010-2013 are extracted from the FAA Termina

(TAF) (http://aspm.faa.gov/main/taf.asp).

2LTOs for military aircraft in all airports, except Luke Air Force Base, are assumed to remain constant from 23PM-10 emissions from aircrafts are calculated by using emission factors from EPA’s guidance, Documenta

NONROAD Model Criteria Air Pollutant Component of the National Emissions Inventory (NEI) for Base YearReport prepared by E.H. Pechan & Associates for U.S. EPA Office of Air Quality Planning and Standards, S

4PM-10 emissions from Ground Support Equipment (GSE) and Auxiliary Power Units (APUs) are calculated 

II - 8
Table II-4

Growth Factors for Other Nonroad Mobile Sources

NONROAD2008 Annual PM-10 Emissions by Source Type for Maricopa County Growth Fa

Source Type 2007 2008 2009 2010 2011 2012 2007 2008 Agricultural Equipment 35.86 34.27 32.74 31.25 29.44 27.28 1.047 1.000 Commercial Equipment 118.35 117.97 117.32 116.26 114.80 111.38 1.003 1.000 Construction and Mining Equipment 1,286.45 1,260.98 1,240.09 1,222.25 1,178.71 1,105.11 1.020 1.000 Industrial Equipment 105.13 102.60 100.81 99.24 97.06 90.98 1.025 1.000 Lawn and Garden Equipment 179.69 182.19 184.91 187.72 190.75 192.37 0.986 1.000 Logging Equipment 0.00 0.00 0.00 0.00 0.00 0.00 1.000 1.000 Pleasure Craft 9.79 9.19 8.61 7.81 7.06 6.37 1.066 1.000 Railroad Equipment 1.15 1.13 1.10 1.07 1.03 0.99 1.023 1.000 Recreational Equipment 45.44 45.58 45.12 44.49 43.65 42.59 0.997 1.000 Total (tons/year) 1,781.87 1,753.90 1,730.69 1,710.09 1,662.50 1,577.08 1.016 1.000 

II - 9
growth factors for total other nonroad mobile source equipment shown at the bottom of the

table were used to back-cast 2008 emissions to 2007 and project 2008 emissions to 2009-

2012. 

ONROAD MOBILE SOURCES

There are three categories of PM-10 emissions from onroad mobile sources: exhaust, tire

wear and brake wear; reentrained dust from paved roads; and travel on unpaved roads and

alleys. Each of these categories is discussed in a separate section below.

Exhaust, Tire Wear and Brake Wear Emissions

The 2008 PEI estimate of PM-10 emissions from exhaust, tire wear and brake wear is

3,144.17 tons. The 2008 PEI emissions were estimated by MAG using the new EPA

MOVES2010a model. The MOVES input assumptions are detailed in Chapter Five of the

2008 PEI (Appendix A, Exhibit 1). 

MAG re-estimated onroad mobile source emissions using the MOVES2010a model and the

latest planning assumptions available in August 2011. The latest planning assumptions

included July 1, 2011 vehicle registration data provided by the Arizona Department of

Transportation. Due to the recession, the 2011 vehicle registrations contain a larger

proportion of older vehicles than the 2010 vehicle registrations used in estimating mobile

source emissions for the 2008 PEI. In addition, the vehicle miles of travel (VMT) and linklevel speeds were based on the latest MAG transportation models, which incorporate a new

truck model and updated volume/delay functions. The traffic assignments produced by the

MAG transportation models in August 2011 had also been validated against the most recent

(2008-2010) traffic counts. Due to these changes in vehicle registrations and transportation

modeling and the use of updated factors to convert from weekday to annual average daily

traffic, the exhaust, tire wear and brake wear emissions estimated with MOVES2010a for

the 2008 base case PM-10 emissions are 3,849.64 tons, which is 22.4 percent higher than

the 2008 PEI. 

The emission rates produced by MOVES for 2007-2012 were applied to VMT estimates for

the PM-10 nonattainment area. For 2008, the MOVES emission rates were applied to VMTs

produced by the 2008 MAG traffic assignment. The 2007 VMT was derived from the 2008

VMT, using historical, pre-recession trends in VMT growth produced by MAG traffic

assignments. The traffic counts MAG has conducted since 2008 indicate that traffic

volumes have not increased at their historical rate. Therefore, for 2009-2012, the MOVES

emission rates were applied to VMT estimates based on the population growth factors in

Table II-1, rather than VMTs output by the MAG traffic assignments. The population

projections shown in Table II-1 take into account the 2010 U.S. Census, as well as the

economic downturn after 2007. In contrast, the MAG traffic assignments utilize the official

population projections adopted by the MAG Regional Council in May 2007. The adopted

projections, which are based on the 2005 Special Census for Maricopa County, significantly

overstate the socioeconomic growth in the area since 2008. MAG is working on new

II - 10
population and employment projections by traffic analysis zone that are consistent with the

2010 U.S. Census, but these will not be available to use as input to the transportation

models until early 2013. In the meantime, the VMT estimates during the recession years

of 2009-2012 are based on the best available population projections for the area shown in

Table II-1. The base case exhaust, tire wear and brake wear emissions for 2007-2012 and

the growth factors, relative to 2008, are shown in Table II-5. 

Reentrained Dust from Paved Roads

The 2008 PEI estimate of PM-10 emissions from dust reentrained by vehicles traveling on

paved roads is 6,694.22 tons. The estimate is based on the new AP-42 equation for paved

roads that was revised by EPA in January 2011. The PEI emissions include a reduction of

1,172.8 tons for PM-10 certified street sweepers purchased by December 31, 2006 with

Congestion Mitigation and Air Quality Improvement (CMAQ) funds. The PEI estimate also

includes reductions of 996.0 tons for five measures in the MAG 2007 Five Percent Plan that

were implemented in 2008. 

The 2008 base case PM-10 emissions for the MAG 2012 Five Percent Plan were developed

using the assumptions in the 2008 PEI, with one exception; the average vehicle weights for

freeways and arterials have been re-estimated using July 1, 2011 vehicle registrations and

the EPA default vehicle weight of 3.18 tons, while the 2008 PEI used July 1, 2010 vehicle

registrations and an average vehicle weight of 3 tons. The new vehicle weights for freeways

(3.91 tons) and arterials (2.73 tons) were derived from July 1, 2011 vehicle registrations and

a 2008 traffic assignment. When weighted by VMT, these freeway and arterial weights

average 3.18 tons. 

Other AP-42 input assumptions used in calculating paved road emissions are consistent

with the 2008 PEI. The silt loadings in grams per square meter are 0.02 for freeways, 0.067

for high traffic arterials (>10,000 average daily traffic (ADT)), and 0.23 for low traffic arterials

(<10,000 ADT). The number of “wet” days per year is 39, while the annual number of days

in the leap year of 2008 was 366.

Applying these inputs to the AP-42 equation produces paved road emission rates of 0.11

grams per VMT for freeways, 0.23 grams per VMT for high traffic arterials, and 0.71 grams

per VMT for low traffic arterials. These emission rates are multiplied by the 2008 annual

average daily VMTs used in the PEI, which are 30,835,329 for freeways, 42,498,543 for high

traffic arterials, and 13,819,127 for low traffic arterials. The resultant uncontrolled paved

road emissions for 2008 are 9,270.34 tons, which is five percent higher than the 2008 PEI

estimate without benefits for street sweepers and the five other measures in the 2007 Plan. 

The uncontrolled paved road emissions do not include credit for PM-10 certified street

sweepers that were purchased in 2001 through 2006. During this six year period, MAG

member agencies purchased 94 PM-10 certified street sweepers to replace conventional

(non-certified) sweepers, increase the frequency of sweeping, and expand the area swept 

II - 11
 Table II-5 

2007-2012 PM-10 Emissions from Exhaust, Tire Wear and Brake Wear

PM-10 Emissions (tons/year) Growth Fac

2007 2008 2009 2010 2011 2012 2007 2008 2

Exhaust 2,943.36 2,835.65 2,647.20 2,371.05 1,843.23 1,407.06 1.038 1.000 0

Tire Wear 245.80 255.82 256.50 257.23 257.94 261.41 0.961 1.000 

Brake Wear 727.66 758.17 767.49 770.58 772.79 787.25 0.960 1.000 

Total 3,916.81 3,849.64 3,671.19 3,398.86 2,873.96 2,455.72 1.017 1.000 0

II - 12
in the PM-10 nonattainment area. The agencies purchased the sweepers with Congestion

Mitigation and Air Quality Improvement (CMAQ) funds and paid a minimum local match of

5.7 percent of the cost of each sweeper. As part of the funding request, the agencies

provided MAG with data on the lane miles to be swept, the traffic volume per lane swept and

the sweeping cycle length. These data have been used to quantify the PM-10 emission

reductions attributable to the PM-10 certified sweepers purchased with CMAQ funds in

2001-2006.

There were 94 PM-10 certified sweepers purchased with CMAQ funds between January 1,

2001 and December 31, 2006. An ADOT street sweeper inventory dated April 2, 2010

indicated that only 72 of these sweepers were still in service as of December 31, 2009. To

be conservative in estimating the emissions reduced by PM-10 certified sweepers, the

benefits of the sweepers that were not in service as of December 31, 2009 have been

removed. In addition, no credit is taken for the one sweeper purchased to replace an older

PM-10 certified sweeper during this period. The sweeper-specific assumptions are shown

in Appendix B, Exhibit 2.

The equations used to quantify the benefit of the PM-10 certified sweepers are documented

in the CMAQ Methodologies (MAG, 2011). The average unswept emission factors used in

calculating the sweeper benefits for non-freeways is 0.35 grams per vehicle mile of travel

(VMT). This represents a 2008 VMT-weighted average of 0.71 grams per VMT for low

traffic arterials and 0.23 grams per VMT for high traffic arterials. Table II-6 shows the

emission rates for sweeping freeways, non-freeways and streets in the Salt River Area with

PM-10 certified and conventional sweepers for sweeping cycle lengths of one to thirty days. 

In converting from daily to annual reductions, it was assumed that a new PM-10 certified unit

would sweep 95 percent of the days during the first year, with the remainder of the time

devoted to routine maintenance and holiday downtime. It was also assumed that the rate

of utilization (and attendant emission reductions) would decline according to the usage

factors shown in Table II-7 due to the need for increased maintenance as the equipment

ages. The usage factors are based on maintenance data provided by agencies requesting

CMAQ funding for a new PM-10 certified sweeper to replace an older PM-10 certified

sweeper. 

The total PM-10 emissions reduction attributable to PM-10 certified street sweepers

purchased in 2001 through 2006 and still in service as of December 31, 2009 is 1,115.77

tons in 2008. The uncontrolled paved road emissions estimate of 9,270.34 tons is reduced

by the benefit of the CMAQ-funded street sweepers, resulting in 2008 base case paved road

emissions of 8,154.57 tons. 

For 2007, 2009, and 2010, the reductions due to the sweepers purchased in 2001-2006 vary

slightly, because the aging of the sweepers and increased downtime reduces the benefits

over time. As a result, the reduction in 2007 is slightly higher than 2008: 1,153.93 tons,

while the reductions in 2009 and 2010 are slightly lower: 1,077.32 tons and 1,029.63 tons,

respectively. The 2008 uncontrolled base case paved road emissions are back-cast 

II - 13
Table II-6 

PM-10 Emission Rates for PM-10 Certified and Conventional Sweepers

Cycle

Length

(days)

Composite Emission Rates (g/VMT) -

PM-10 Certified Sweeper

Composite Emission Rates (g/VMT) -

Conventional Sweeper

Freeway Non-Freeway Salt River Freeway Non-Freeway Salt River

1 0.031 0.098 0.364 0.065 0.208 0.778

2 0.037 0.118 0.441 0.070 0.223 0.832

3 0.043 0.137 0.510 0.074 0.237 0.884

4 0.048 0.154 0.574 0.079 0.250 0.934

5 0.053 0.170 0.634 0.083 0.263 0.983

6 0.058 0.185 0.692 0.087 0.276 1.029

7 0.063 0.200 0.746 0.090 0.286 1.069

8 0.067 0.214 0.799 0.092 0.294 1.099

9 0.072 0.228 0.850 0.094 0.300 1.122

10 0.075 0.240 0.895 0.096 0.305 1.141

11 0.079 0.250 0.933 0.097 0.309 1.156

12 0.081 0.258 0.964 0.098 0.313 1.168

13 0.083 0.265 0.990 0.099 0.316 1.179

14 0.085 0.271 1.013 0.100 0.318 1.188

15 0.087 0.277 1.033 0.101 0.320 1.196

16 0.088 0.281 1.050 0.101 0.322 1.203

17 0.090 0.285 1.065 0.102 0.324 1.209

18 0.091 0.289 1.078 0.102 0.325 1.215

19 0.092 0.292 1.091 0.103 0.327 1.220

20 0.093 0.295 1.101 0.103 0.328 1.224

21 0.094 0.298 1.111 0.103 0.329 1.228

22 0.094 0.300 1.120 0.104 0.330 1.231

23 0.095 0.302 1.128 0.104 0.331 1.235

24 0.096 0.304 1.136 0.104 0.331 1.238

25 0.096 0.306 1.143 0.104 0.332 1.241

26 0.097 0.308 1.149 0.105 0.333 1.243

27 0.097 0.309 1.155 0.105 0.333 1.245

28 0.098 0.311 1.160 0.105 0.334 1.248

29 0.098 0.312 1.165 0.105 0.335 1.250

30 0.098 0.313 1.170 0.105 0.335 1.252

II - 14
Table II-7 

Usage Factors for PM-10 Certified Street Sweepers

 Usage Factor Table

Year of Use

Usage

Factor

1st 0.950

2nd 0.919

3rd 0.888

4th 0.857

5th 0.826

6th 0.795

7th 0.764

8th 0.734

9th 0.703

10th+ 0

II - 15
to 2007 based on the vehicle miles of travel (VMT) estimated by the MAG transportation

models for 2008 versus 2007. The reduction for sweepers purchased in 2001-2006

(1,153.93 tons) is then subtracted to derive 2007 base case paved road emissions. To

account for the economic recession, the 2008 uncontrolled base case paved road emissions

are projected to 2009 and 2010 using the Marshall Vest population projections in Table II-1. 

The reductions for sweepers purchased in 2001-2006 (1,077.32 tons in 2009 and 1,029.63

tons in 2010) are then applied to estimate 2009 and 2010 base case paved road emissions. 

The 2010 base case paved road emissions with street sweeper reductions are projected to

2011-2012 based on the population growth factors in Table II-1. 

Travel on Unpaved Roads and Alleys

The 2008 PEI estimate of PM-10 emissions from vehicles traveling on unpaved roads and

alleys is 11,710.70 tons. This estimate is based on the EPA AP-42 equation for unpaved

roads (assuming a speed of 25 mph) and unpaved alleys (assuming a speed of 10 mph). 

The PEI estimate included a reduction of 2,065.4 tons for four measures in the MAG 2007

Five Percent Plan that were implemented in 2008. Assumptions for calculating base case

unpaved road and alley emissions for the MAG 2012 Five Percent Plan are consistent with

the 2008 PEI, with the exception of the average daily traffic (ADT) on unpaved alleys and

the ADT, speeds, and miles assumed for private unpaved roads. 

MAG conducted traffic counts on a statistically significant sample of unpaved alleys and

private unpaved roads in the PM-10 nonattainment area in February 2011. The survey

indicated that the ADT on unpaved alleys should be 4, rather than 10, and the ADT on

private unpaved roads should be 26, rather than 28. 

In August-September 2011, MAG conducted a private unpaved road inventory. The MAG

contractor drove most of the private unpaved roads identified in the MAG 2009 Unpaved

Road Inventory (URI) and collected data on the location, length, condition and function of

each road. The 2009 URI estimate of 1,270.6 miles of private unpaved roads was based

on a GIS analysis of aerial photographs, rather than actual field data. The 2011 field

inventory concluded that there are 927.3 miles of private unpaved roads, which is 343.3

miles lower than estimated by the 2009 URI. The principal reason for this difference was

the mis-classification of driveways, trails, utility and canal roads, barricaded routes, and

inaccessible rights-of-way as private unpaved roads. The contractor also reported that the

maximum speed that could be driven on the private unpaved roads was 15 to 20 miles per

hour, rather than the 25 miles per hour assumed in the 2008 PEI. Unlike public unpaved

roads, which typically carry higher traffic volumes and are better-maintained, private

unpaved roads have rough surfaces and poor alignments, which reduces vehicle speeds. 

To be conservative, the speed used in quantifying the private unpaved road emissions for

the MAG 2012 Five Percent Plan was assumed to be 20 mph, which is the higher end of the

range. 

Other inputs to the AP-42 equation for paved roads are consistent with the 2008 PEI. These

include a silt content of 11.9 percent, a soil moisture content of 0.5 percent, and average

II - 16
speeds of 25 mph on public unpaved roads and 10 mph on unpaved alleys. The average

number of “wet” days in 2008 was 36, with the annual number of days in 2008, a leap year,

of 366. The resultant emission factors for 2008 are 660.16 grams per VMT for public

unpaved roads, 590.45 grams per VMT for private unpaved roads, and 417.45 grams per

VMT for unpaved alleys. These factors are applied to annual average daily 2008 VMT

estimates of 19,956 for public unpaved roads, 22,255 for private unpaved roads, and 2,600

for unpaved alleys in the PM-10 nonattainment area. Converting to annual emissions

results in total 2008 base case emissions from public unpaved roads, private unpaved roads

and unpaved alleys of10,312.22 tons. 

Base case public unpaved road and alley emissions are held constant between 2008 and

2007. The 2008 private unpaved road emissions are back-cast to 2007 assuming a growth

rate of 1.46 percent between 2007 and 2008. This growth rate is based on a longitudinal

analysis of historical lot split data conducted by MAG that showed an average annual

increase in private unpaved road mileage, prior to the recession, of 1.46 percent. Due to

the economic downturn in 2008, base case emissions for public and private unpaved roads

and alleys are held constant in 2008 through 2012.

SUMMARY OF BASE CASE EMISSIONS

Table II-2 summarizes the 2007-2012 base case PM-10 emissions by source category that

were developed using the methods and assumptions described in this chapter. The base

case emissions include no reduction credit for measures quantified in the MAG 2012 Five

Percent Plan. Credit for rule effectiveness rates in 2007 has been applied to the base case

emissions for construction, other windblown sources, mining/quarrying, and travel on

industrial roads. In addition, reduction credit for PM-10 certified street sweepers purchased

with CMAQ funds in 2001 through 2006 and still in service on December 31, 2009 was

applied to the base case paved road emissions. The benefits quantified for increases in rule

effectiveness and contingency projects in the MAG 2012 Five Percent Plan are discussed

in the next two chapters of the TSD. 

The total 2012 base case emissions are 49,673.01 tons, which is 9,545.37 tons (16.1

percent) lower than the 2007 emissions. Most of this decrease is due to reductions in

construction activity between 2007 and 2012. The sources contributing the largest share

of base case PM-10 emissions in 2012 are unpaved roads and alleys, paved roads,

construction and other windblown sources (vacant lots). 

The next chapter discusses the methods and assumptions used to quantify the increases

in rule effectiveness for Maricopa County Rules 310, 310.01 and 316. These increases are

sufficient to demonstrate annual five percent reductions in PM-10 emissions between the

base year of 2007 and the attainment year of 2012. Credit for the increases in rule

effectiveness is applied to the base case emissions in Table II-2 to meet the annual five

percent reduction requirement of Clean Air Act Section 189(d). 

II - 17
REFERENCES

MAG, 2011. Methodologies for Evaluating Congestion Mitigation and Air Quality

Improvement Projects. Maricopa Association of Governments. September 30, 2011.

II - 18
III. EVALUATION OF RULE EFFECTIVENESS

This chapter describes the increases in rule effectiveness that have been quantified to meet

the annual five percent reduction requirement in Section 189(d) of the Clean Air Act. The

PM-10 emission reductions due to increased rule effectiveness are also used in

demonstrating attainment, as discussed in Chapter V of the TSD.

Increases in rule effectiveness have been achieved due to strengthened enforcement and

increased compliance with Maricopa County Rules 310, 310.01 and 316 in 2008-2010. 

Rule effectiveness rates are held constant from 2010 forward except for a 1% increase in

2012 on Rule 310.01 windblown dust sources due to the new Dust Action General Permit 

measure. 

In 2009 EPA approved Rule 316, which controls emissions from permitted sources of nonmetallic mineral processing and mining and quarrying operations, as part of the State

Implementation Plan for the Maricopa County PM-10 Nonattainment Area (SIP) (EPA,

2009). In 2010 EPA approved Rule 310, which controls emissions from permitted

earthmoving sources, and Rule 310.01, which controls sources such as vacant lots and

public unpaved roads, as part of the SIP (EPA, 2010). 

The benefit of increased compliance with these rules has been quantified, using actual

inspection data and a methodology developed by the Maricopa County Air Quality

Department, in consultation with EPA. The methodology for quantifying rule effectiveness

(RE) is described in the 2008 PEI (Appendix A, Exhibit 1). The RE rates calculated for

2007 through 2010 using this EPA-approved methodology are shown in Table III-1. 

Table III-1 also includes base case emissions (with 2007 RE rates), controlled emissions

(with increased RE rates), and emission reductions (obtained by subtracting controlled

emissions from base case emissions) for each subcategory. The derivation of the base

case emissions is discussed in Chapter II of the TSD. For all years, the base case

emissions assume the 2007 RE rates of 76 percent for Rule 310, 85 percent for Rule

310.01, and 40 percent for Rule 316, while the controlled emissions incorporate the actual

RE rate calculated for each year (2008-2010). The RE rates used in calculating controlled

emissions are held constant after 2010. 

As shown in Table III-1, the rule effectiveness (RE) rates increased dramatically between

2007 and 2008. Since 2008, the RE rates have continued to increase on an annual basis. 

Between 2007 and 2010, Rule 310 RE increased from 76 to 94 percent; Rule 310.01 RE

increased from 85 to 96 percent; and Rule 316 RE increased from 40 to 73 percent.

In addition to the increases in rule effectiveness discussed above, the 2012 Plan takes

credit for one new measure, the Dust Action General Permit, which were passed by the

Arizona Legislature in April 2011. This new measure is expected to increase rule

effectiveness for Rule 310.01 by one percent during high wind hours, resulting in the 2012

RE rate of 97 percent for windblown vacant land, open space, landfills and test tracks, as

III - 1
Table III-1

Impact of Increased Rule Effectiveness on 2008-2012 PM-10 Emissions

Categories Affected by Rule Effectiveness

Base Case Emissions (tons/year) Ru

2007 2008 2009 2010 2011 2012 2007 20

Residential Construction 3,423 2,815 1,939 1,656 1,602 1,627 76% Commercial Construction 8,205 6,748 4,649 3,971 3,839 3,901 76% Road Construction 4,150 3,412 2,351 2,008 1,942 1,973 76% All Other Earthmoving 328 270 186 159 154 156 76% Non-metallic mineral mining 306 290 257 246 247 260 40% Mining & Quarrying 256 242 214 205 206 217 40% Industrial paved/unpaved road travel 771 728 645 618 621 654 40% Windblown Agriculture 448 448 448 448 448 448 n/a Windblown Construction 566 566 566 566 566 566 76% Windblown Vacant, Open, Landfill, Test Tracks 5,430 5,430 5,430 5,430 5,430 5,430 85% Windblown Sand & Gravel, Mining 190 190 190 190 190 190 40% TOTALS: 24,073 21,139 16,876 15,497 15,244 15,422

Categories Affected by Rule Effectivenss

Controlled Emissions (tons/year) Benefits 

2007 2008 2009 2010 2011 2012 2008 20

Residential Construction 3,423 1,692 1,056 807 780 793 1,122 Commercial Construction 8,205 4,057 2,531 1,935 1,871 1,901 2,691 2Road Construction 4,150 2,052 1,280 979 946 961 1,361 1All Other Earthmoving 328 162 101 77 75 76 108 Non-metallic mineral mining 306 188 152 132 132 139 102 Mining & Quarrying 256 157 127 110 110 116 85 Industrial paved/unpaved road travel 771 472 382 331 333 351 256 Windblown Agriculture 448 448 448 448 448 448 0 Windblown Construction 566 391 366 341 341 341 175 Windblown Vacant, Open, Landfill, Test Tracks 5,430 3,938 3,788 3,788 3,788 3,639 1,492 1Windblown Sand & Gravel, Mining 190 132 123 113 113 113 58 TOTALS: 24,073 13,689 10,353 9,062 8,939 8,879 7,450 6

III - 2
shown in Table III-1. 

EPA allows an emission reduction to be taken for the new Dust Action General Permit, as

an emerging measure (EPA, 2004). According to EPA guidance, emerging measures do

not have the same high level of certainty as traditional measures for quantification purposes

in a State Implementation Plan. The PM-10 emission reduction increment necessary to

demonstrate attainment in 2012, (i.e., total 2012 base case emissions in Table II-2 of

49,673 tons minus total 2012 emissions with increased rule effectiveness in Table III-2 of

43,130 tons), is 6,543 tons. EPA allows up to six percent of this increment, in this case,

a maximum of 393 tons, to be credited to emerging and voluntary measures in the SIP. 

The one percent increase in RE for Rule 310.01 during high wind hours will reduce PM-10

emissions by 149.27 tons in 2012. Since this reduction is less than 393 tons, benefit for

this new measure may be used in meeting the annual five percent reduction requirement

and demonstrating attainment in this Plan.

As required by EPA’s emerging and voluntary measure guidance, Maricopa County has

made a commitment to retrospectively assess the performance of the Dust Action General

Permit. MCAQD will evaluate the effectiveness of Rules 310, 310.01 and 316 to ensure

that this measure achieves at least a 149 ton reduction during calendar year 2012. The

County’s commitment and the method to be used in calculating rule effectiveness are

described in Chapter Four and Appendix C, Exhibit 2. 

As discussed above, increases in Rule Effectiveness (RE) for Rules 310, 310.01 and 316

have been quantified to meet the annual five percent reductions required in Section 189(d)

of the Clean Air Act. The annual five percent reduction target was calculated by multiplying

the total 2007 PM-10 emissions in Table II-2 (59,218.38 tons) by five percent, which results

in 2,960.92 tons. To meet the 189(d) requirement, the 2008 emissions with increased rule

effectiveness must be at least 2,961 tons less than the 2007 base case emissions. Each

year after 2008 imposes yet another 2,961 ton reduction requirement. Thus, the

cumulative reduction requirements (relative to 2007 base case emissions) are at least

5,922 tons in 2009, 8,883 tons in 2010, 11,844 tons in 2011, and 14,805 tons in 2012. 

Table III-2 shows the impact of the increases in rule effectiveness on PM-10 emissions in

2008 through 2012. A comparison of the five percent reduction requirements with

reductions actually achieved by increased rule effectiveness is provided at the bottom of

the table. The actual reductions represent the difference between the total 2007 base case

emissions in Table II-2 minus the total emissions with increased rule effectiveness in Table

III-2 for 2008-2012. The total reduction in PM-10 emission between 2007 and 2012 with

the increases in RE is 16,088.55 tons, which represents a 27.2 percent reduction in 2007

base case emissions. 

Table III-3 confirms that the annual five percent reduction targets are met in 2008-2012 and

there is a surplus margin of benefit in each year. The total surplus in 2012 is 1,284 tons. 

This surplus is needed to model attainment at all monitors in the PM-10 nonattainment

area. The rollback modeling that demonstrates attainment with the

III - 3
Table III-2

2008-2012 PM-10 Emissions with Increased Rule Effectiveness

Source Category

2008 2009 2010 2011 2012

(tons/year)

POINT 149.84 132.76 127.18 127.69 134.59

AREA

Fuel combustion 1,300.65 1,307.15 1,311.07 1,316.32 1,328.17

Commercial cooking 993.04 998.01 1,001.00 1,005.00 1,014.05

Construction (includes windblown dust) 8,354.86 5,333.29 4,139.15 4,013.81 4,072.58

Tilling, harvesting and cotton ginning 893.20 893.20 893.20 893.20 893.20

Travel on unpaved farm roads 731.03 731.03 731.03 731.03 731.03

Livestock 260.95 260.95 260.95 260.95 260.95

Travel on unpaved parking lots 2,421.51 2,433.62 2,440.92 2,450.68 2,472.74

Offroad recreational vehicles 2,180.16 2,191.06 2,197.63 2,206.42 2,226.28

Leaf blowers 894.98 899.45 902.15 905.76 913.91

Windblown agriculture 447.85 447.85 447.85 447.85 447.85

Other windblown sources 3,937.57 3,788.33 3,788.33 3,788.33 3,639.06

Fires 496.71 496.71 496.71 496.71 496.71

Mining/quarrying (includes windblown dust) 476.33 401.27 354.88 355.85 368.94

Travel on industrial paved/unpaved roads 472.36 382.21 331.37 332.70 350.67

Other industrial sources 976.01 864.74 828.43 831.74 876.65

NONROAD

Aircraft 183.80 151.52 141.54 143.44 145.50

Airport ground support equipment 26.99 23.32 20.94 20.11 19.90

Locomotives 34.16 34.16 34.16 34.16 34.16

Other nonroad equipment 1,682.91 1,660.64 1,640.88 1,595.22 1,513.25

ONROAD

Exhaust 2,835.65 2,647.20 2,371.05 1,843.23 1,407.06

Tire wear 255.82 256.50 257.23 257.94 261.41

Brake wear 758.17 767.49 770.58 772.79 787.25

Paved roads 8,154.57 8,213.92 8,289.47 8,322.90 8,421.72

Unpaved roads and alleys 10,312.22 10,284.04 10,284.0410,284.04 10,312.22

Totals 49,231.34 45,600.42 44,061.7543,437.87 43,129.84

5% Reduction Targets (tons/year) 2,961.00 5,922.00 8,883.0011,844.00 14,805.00

Actual Plan Reductions (tons/year) 9,987.05 13,617.97 15,156.6415,780.51 16,088.55

III - 4
Table III-3

PM-10 Emission Reductions and Five Percent Reduction Requirements

Year

5% Reduction

Requirement

Total PM-10 Emission

Reductions due to Increases

in Rule Effectiveness

Excess Benefit = Total PM-10

Emission Reductions minus 5%

Reduction Requirement

(tons/year) (tons/year) (tons/year) (%)

2008 2,961 9,987 7,026 237%

2009 5,922 13,618 7,696 130%

2010 8,883 15,157 6,274 71%

2011 11,844 15,781 3,937 33%

2012 14,805 16,089 1,284 9%

III - 5
increased rule effectiveness quantified in this chapter is described in Chapter V. 

The annual incremental reductions that demonstrate reasonable further progress (RFP)

between 2007 and 2012 are graphed in Figure III-1. After 2007, the RFP line represents

total emissions in the PM-10 nonattainment area after credit is applied for the increases in

rule effectiveness quantified in this chapter. The RFP requirement is met by showing

incremental emission reductions sufficient to maintain linear progress towards attainment. 

The annual emissions in Figure III-1 show a downward linear trend. The slope of the line

becomes less steep after 2008, because most of the measures in the MAG 2007 Five

Percent Plan that increased compliance with Rules 310, 310.01 and 316 were implemented

in 2008. Figure III-1 demonstrates that RFP will be achieved between 2007 and the

attainment date of 2012. 

This chapter has quantified the increases in rule effectiveness between 2008 and 2012 in

order to meet the five percent reduction and reasonable further progress requirements of

the Clean Air Act. Chapter V shows how these increases in rule effectiveness are also

sufficient to demonstrate attainment by 2012 through rollback modeling. The next chapter

discusses the quantification of additional PM-10 emission reductions needed to meet the

contingency requirements of the Clean Air Act.

III - 6
Figure III-1

Demonstration of Reasonable Further Progress

III - 7
REFERENCES

EPA, 2004. Incorporating Emerging and Voluntary Measures in a State Implementation

Plan. EPA Office of Air Quality Standards. September 2004.

III - 8
IV. EVALUATION OF CONTINGENCY PROJECTS

The increases in rule effectiveness due to measures in the MAG 2007 Five Percent Plan

were quantified in Chapter III to demonstrate annual five percent reductions and reasonable

further progress (RFP). The PM-10 emission reductions attributable to increased rule

effectiveness are also used to model attainment, as discussed in Chapter V. This chapter

discusses emission reductions above and beyond the increases in rule effectiveness that

meet the contingency requirements of the Clean Air Act. 

Section 172(c)(9) of the Clean Air Act requires that nonattainment plans contain

contingency measures. Such measures are to be undertaken without further action by the

State or the EPA Administrator if the area fails to make reasonable further progress or meet

the standard by the attainment date. 

The contingency measures must achieve emission reductions above and beyond those

relied upon for progress (five percent reductions, milestones, and reasonable further

progress) and the modeled attainment demonstration. The benefits of the contingency

measures must not be required to show attainment and can not hasten attainment. 

Although there is no mandated emissions reduction level, EPA has recommended that

contingency measures provide the emissions reduction equivalent of one year’s average

increment of RFP. EPA encourages early implementation of contingency measures, so

that emissions are reduced as expeditiously as practicable (EPA, 1993). The contingency

requirement is met in the MAG 2012 Five Percent Plan by quantifying the benefits of PM-10

reduction projects that were implemented in 2008-2011. 

A large number of PM-10 reduction projects have been implemented in the nonattainment

area since the MAG 2007 Five Percent Plan was submitted to EPA in December 2007. As

required for contingency measures, the emission reductions attributable to these projects

are above and beyond the credit taken for the measures in Chapter Five. In the Fall of

2011, MAG updated the inventory of PM-10 reduction projects in the nonattainment area

that were completed in 2008-2011 by the cities, towns, Maricopa County, Pinal County, the

Arizona Department of Transportation (ADOT) and the Indian communities. These projects

included paving and stabilizing unpaved roads, alleys and shoulders; reducing speed limits

on unpaved roads and alleys; and overlaying state highways with rubberized asphalt. In

addition, MAG quantified the benefit for the freeways being swept by an ADOT contractor

with PM-10 certified street sweepers and the arterials being swept by local jurisdictions with

PM-10 certified street sweepers purchased with Congestion Mitigation and Air Quality

Improvement (CMAQ) funds between January 1, 2007 and December 31, 2009. 

The RFP graph shown in Figure III-1 indicates that total PM-10 emissions, after reductions

due to increased rule effectiveness in 2008-2012, are 43,129.84 tons in 2012. Subtracting

these 2012 emissions from the total 2007 emissions of 59,218.38 tons and dividing by five

years produces a contingency target of 3,218 tons. Therefore, completed projects that

reduce total PM-10 emissions by at least 3,218 tons in 2012 must be quantified to meet the

contingency requirement.

IV - 1
The emission reductions for all projects quantified to meet the contingency requirement are

summarized in Table IV-1. This table includes the benefits of PM-10 certified street

sweeping on freeways and arterials and PM-10 reduction projects completed in 2008-2011

that paved and stabilized unpaved roads, alleys and shoulders; reduced speed limits; and

overlaid highways with rubberized asphalt. 

These projects were implemented in the PM-10 nonattainment area by twenty-one cities

and towns, Maricopa County, Pinal County, ADOT and the Gila River Indian Community. 

All of the projects for which credit was taken were open to traffic between January 1, 2008

and September 30, 2011. The assumptions used in quantifying the PM-10 reductions

needed to meet the contingency target are discussed below for each of the five project

categories shown in Table IV-1.

PM-10 CERTIFIED STREET SWEEPING

PM-10 certified street sweepers meet the certification criteria specified in South Coast Air

Quality Management District Rule 1186. PM-10 certified street sweepers reduce the silt

loadings on paved roads, relative to the use of conventional sweepers. The reentrainment

of dust by vehicles traveling on the roads is reduced, which, in turn, decreases emissions

and ambient concentrations of PM-10. 

ADOT Contracted Sweeping

A new contract awarded by the Arizona Department of Transportation (ADOT), effective 

February 20, 2010, requires freeways, ramps and frontage roads in the PM-10

nonattainment area to be swept with PM-10 certified street sweepers. The ADOT contract

also requires sweeping frequencies of every seven days for freeways and every fourteen

days for ramps and frontage roads.

 

A map of the specific highways being swept with PM-10 certified units by the ADOT

contractor is provided in Figure IV-1. The emission reduction calculations are shown in

Table IV-2. 

The vehicle miles of travel (VMT) for freeways and ramps/frontage roads being swept in

2010 was estimated by summing the traffic volumes and link lengths from a 2010 traffic

assignment for the routes identified in Figure IV-1. In 2010, the freeways being swept with

PM-10 certified sweepers by the ADOT contractor carry nearly 30 million VMT per day,

which is 86 percent of the total daily freeway VMT in the PM-10 nonattainment area. All

of the freeways and ramps/frontage roads being swept by the ADOT contractor carry about

35 percent of the total daily VMT in the nonattainment area.

The PM-10 emission reductions were derived by subtracting the emission rate for PM-10

certified sweepers from the emission rate for conventional (non-certified) sweepers and 

IV - 2
Table IV-1 

2008-2012 PM-10 Emission Reductions for Contingency Projects

Completed Projects Implementing Entities

2008 200

Sweep streets with PM-10 certified sweepersContracted sweeping of freeways, ramps and frontage roads100% compliant, effective 2/20/1025 PM-10 certified sweepers purchased with CMAQ funds:1/1/07-12/31/09

ADOT 0 

Cities, towns 59.04 115

Total for Street Sweeping 59.04 115

Pave or stabilize existing public dirt roads and alleysPaving/stabilization projects completed in 2008-2011 Cities, towns, Maricopa and Pinal County,

and Gila River Indian Community 461.30 1,351

Total for Road/Alley Paving/Stabilization 461.30 1,351

Lower speed limits on dirt roads and alleysSpeed limits lowered in 2008-2011 Cities, towns, Maricopa County 3.61 78

Total for Lower Speed Limits 3.61 78

Pave or stabilize unpaved shouldersPaving/stabilization projects completed in 2008-2011 Cities, towns, Maricopa County 173.31 241

Total for Shoulder Paving/Stabilizing 173.31 241

Repave or overlay paved roads with rubberized asphaltRubberized asphalt overlays completed in 2008-2011 ADOT 0 2

Total for Overlays 0 2

Total for Completed Projects 697.25 1,790

IV - 3
Figure IV-1

Map of Highways in the PM-10 Nonattainment Area Swept by ADOT 

IV - 4
Table IV-2

PM-10 Emission Reductions for ADOT Sweeping

Facilities Swept in the

PM-10Nonattainment Area

VMT Swept

in 2010

PM-10 reduction in tons/year

2008 2009 2010* 2011** 2012**

Freeways 29,964,835 0.00 0.00 282.58 328.76 331.33

Ramps/Frontage Roads 2,153,217 0.00 0.00 11.01 12.81 12.91

Total 32,118,052 0.00 0.00 293.59 341.57 344.24

*2010 reductions are multiplied by 0.863 to reflect the start date of the new ADOT contract - 2/20/10

**2011-2012 emission reductions are grown from 2010, based on 3rd quarter 2011 population projections

published by Marshall vest, University of Arizona, for the Phoenix-Mesa metro area (See Table II-1)

Contract Requires Sweeping Cycle of 7 Days

PM-10 EFs (g/mi) Non PM-10 PM-10 Difference in g/mi

Freeways 0.090 0.063 0.027

Contract Requires Sweeping Cycle of 14 Days

PM-10 EFs (g/mi) Non PM-10 PM-10 Difference in g/mi

Ramps/Frontage Roads 0.100 0.085 0.015

IV - 5
multiplying this difference by the VMT (i.e., for freeways or ramps/frontage roads). The

emission rates for sweeping cycle lengths of one to thirty days on freeways, non-freeways,

and all roads in the Salt River Area are shown in Table II-6. The unswept emission factor

based on the new EPA AP-42 emissions equation for paved roads is 0.11 grams per VMT

for freeways and 0.35 grams per VMT for ramps/frontage roads. Other assumptions used

in developing the street sweeping emission rates in Table IV-2 are detailed in the

Methodologies for Evaluating Congestion Mitigation and Air Quality Improvement Projects

(MAG, 2011). 

PM-10 Certified Street Sweepers Purchased with CMAQ Funds

PM-10 certified street sweepers reduce PM-10 emissions generated by vehicles traveling

on paved roads. Therefore, purchase of these sweepers is eligible for federal Congestion

Mitigation and Air Quality Improvement (CMAQ) funding. Since 2001, more than 150 PM10 certified sweepers have been purchased with CMAQ funds by MAG member agencies. 

When purchasing a sweeper with CMAQ funds, the agency must provide a local match of

at least 5.7 percent of the cost of the sweeper. 

PM-10 certified sweepers are eligible for MAG CMAQ funds if they replace a conventional

sweeper, replace a PM-10 certified unit that is at least eight years old, increase the

sweeping frequency, expand the area that is swept, or a combination of these functions. 

The equations used to calculate the benefits of the CMAQ-funded sweepers are described

in the CMAQ Methodologies (MAG, 2011). 

Data on sweeping frequency, lane miles swept and average weekday traffic per lane mile

swept is provided to MAG by the agency requesting funds to purchase the sweeper. The

agency also identifies the functions to be performed by the new sweeper. If the sweeping

frequency or area is to be increased, the agency provides the frequencies or lane miles to

be swept before and after deployment of the new sweeper. 

Data provided by the requesting agencies is applied to calculate the PM-10 emission

reductions associated with each purchased sweeper. The detailed assumptions used to

calculate the emission reductions for the sweepers purchased between January 1, 2001

and December 31, 2006 are discussed in Chapter II under Reentrained Dust from Paved

Roads. These reductions were applied to the 2007-2012 base case emissions. 

Contingency reduction credit is taken for 25 PM-10 certified sweepers purchased with

CMAQ funds between January 1, 2007 and December 31, 2009. There were 28 sweepers

purchased during this period, but no credit is taken for the three sweepers that replaced

older PM-10 certified units. The methods used to calculate the benefit of these sweepers

is consistent with those described in Chapter II. The sweeper-specific assumptions are

shown in Appendix B, Exhibit 2. The total emission reductions attributable to these 25

sweepers is 153.20 tons in 2010. The 2010 credit is projected to 2011 and 2012 based on

the population growth factors in Table II-1.

IV - 6
PAVING AND STABILIZING UNPAVED ROADS AND ALLEYS

In September 2011, MAG contacted its member agencies to request detailed information

on paving and stabilization of unpaved road and alley projects that had been implemented

in January 2008- September 2011. The information collected included the location of the

projects, the year of completion, the length in miles, average daily traffic before paving,

whether the unpaved surface was stabilized prior to paving, and the funding source. This

section describes the paving and stabilization projects that were completed and open to

traffic in 2008 through 2011 and the associated PM-10 emission reductions. The

assumptions used in calculating the emission rates for unpaved roads and alleys are

consistent with those described under Travel on Unpaved Roads and Alleys in Chapter II. 

A map showing the location of the road and alley paving projects completed between

January 2008- September 2011 is presented in Figure IV-2.

The benefits of paving a public unpaved road is 660.16 minus 1.47 grams per VMT or

658.69 grams per VMT paved. The benefits of paving an unpaved alley is 417.45 minus

1.47 grams per VMT or 415.98 grams per VMT paved. The 1.47 grams per VMT

represents the average emission rate for a paved road or alley without paved shoulders or

curb and gutter. These emission rates are multiplied by the estimated VMT on each road

before it is paved. If the unpaved road was stabilized prior to paving, the reduction credit

is reduced by 50 percent. Credit for paving projects is only taken in the years after the

project was completed. For example, credit for a paving project completed in 2009 is taken

in 2010 through 2012; no credit is taken in 2009.

The benefit of projects that stabilize unpaved roads and alleys is calculated using the same

paving factors, but the benefit is reduced by 50 percent. Credit for stabilization projects is

only taken in the single year that the project was completed. For example, credit for a

stabilization project completed in 2009 is taken only in 2009.

Table IV-3 shows the miles and PM-10 benefits of paving and stabilizing unpaved roads

and alleys in the PM-10 nonattainment area by jurisdiction. A summary of the paving and

stabilization project mileage and PM-10 reductions is shown at the bottom of the table. 

Twenty cities and towns, Maricopa and Pinal Counties, and the Gila River Indian

Community reported information on paving and stabilization projects completed in January

2008-September 2011. During this period, 83.21 miles of unpaved roads and 133.69 miles

of unpaved alleys were paved. Another 144.75 miles of unpaved roads and 500.66 miles

of unpaved alleys were stabilized. The total PM-10 emissions reduced by the paving and

stabilization of unpaved roads and alleys is 2,625.41 tons in 2012. 

It is important to note that no credit is taken for stabilization projects in 2012, because these

projects have not yet been implemented. It is clear, however, based on the stabilization

projects that were implemented in 2008-2011, that some jurisdictions will be stabilizing

unpaved roads and alleys in 2012 and therefore, the reduction credit calculated for paving

unpaved roads and alleys in 2012 is conservative.

IV - 7
IV - 8
Table IV-3

PM-10 Reductions for Paving and Stabilizing Unpaved Roads/Alleys

Jurisdiction 2008 2009 2010 2011 2012

Total Miles

Paved/Stabilized

Apache Junction

Miles of roads paved 8.72 2.00 0.77 11.49

Miles of roads stabilized 0.25 0.25

Miles of alleys stabilized 4.00 0.04 4.04

Total miles of paved/stabilized 12.97 2.04 0.77 0.00 0.00 15.78

PM-10 reductions (tons/year) 1.94 41.61 50.23 53.90 54.05

Avondale

Miles of roads stabilized 0.22 0.22

Miles of alleys stabilized 5.50 2.79 8.29

Total miles of paved/stabilized 0.00 5.50 0.22 2.79 0.00 8.51

PM-10 reductions (tons/year) 0.00 1.84 1.05 4.45 0.00

Buckeye

Miles of roads paved 2.50 1.66 1.30 0.30 5.76

Miles of roads stabilized 0.63 0.63

Miles of alleys paved 0.07 0.07

Miles of alleys stabilized 0.86 0.86

Total miles of paved/stabilized 3.99 1.73 1.30 0.30 0.00 7.32

PM-10 reductions (tons/year) 3.30 283.57 407.10 425.06 427.66

Cave Creek

Miles of roads stabilized 10.00 10.00 10.00 10.80 40.80

Miles of alleys stabilized 2.00 2.00 2.00 2.00 8.00

Total miles of paved/stabilized 12.00 12.00 12.00 12.80 0.00 48.80

PM-10 reductions (tons/year) 48.51 48.37 48.37 52.19 0.00

Chandler

Miles of roads paved 1.00 1.00

Miles of alleys stabilized 10.64 15.80 13.40 39.84

Total miles of paved/stabilized 11.64 15.80 13.40 0.00 0.00 40.84

PM-10 reductions (tons/year) 3.57 29.67 28.87 24.38 24.45

El Mirage

Miles of roads stabilized 3.40 3.40

Miles of alleys paved 0.50 0.50

Miles of alleys stabilized 0.50 0.50

Total miles of paved/stabilized 4.40 4.40

PM-10 reductions (tons/year) 15.53 0.33 0.33 0.33 0.34

Fountain Hills

Miles of alleys paved 0.19 0.25 0.45 0.89

PM-10 reductions (tons/year) 0.00 0.59 4.40 15.06 15.10

IV - 9
Jurisdiction 2008 2009 2010 2011 2012

Total Miles

Paved/Stabilized

Gilbert

Miles of roads stabilized 3.62 3.62 3.62 0.75 11.61

Miles of alleys stabilized 3.00 3.00

Total miles of paved/stabilized 3.62 6.62 3.62 0.75 0.00 14.61

PM-10 reductions (tons/year) 17.32 18.27 17.27 3.58 0.00

Glendale

Miles of alleys stabilized 0.25 0.25

PM-10 reductions (tons/year) 0.08 0.00 0.00 0.00 0.00

Goodyear

Miles of roads paved 3.40 1.25 4.65

PM-10 reductions (tons/year) 0.00 184.13 214.61 214.61 215.20

Gila River Indian Community

Miles of roads paved 3.40 5.00 1.00 9.40

PM-10 reductions (tons/year) 0.00 156.63 278.53 302.91 303.74

Litchfield Park

Miles of alleys paved 1.60 1.60

PM-10 reductions (tons/year) 0.00 0.54 0.54 0.54 0.54

Maricopa County

Miles of roads paved 1.05 4.38 2.00 10.68 18.11

Miles of roads stabilized 0.86 0.86

Total miles of paved/stabilized 1.05 4.38 2.00 11.54 0.00 18.97

PM-10 reductions (tons/year) 0.00 38.13 155.98 238.79 461.56

Mesa

Miles of alleys stabilized 1.50 0.26 0.20 1.96

PM-10 reductions (tons/year) 0.50 0.09 0.07 0.00 0.00

Peoria

Miles of roads stabilized 1.00 1.00 1.00 6.10 9.10

PM-10 reductions (tons/year) 4.78 4.77 4.77 29.10 0.00

Phoenix

Miles of roads paved 5.70 1.54 3.16 10.40

Miles of alleys stabilized 66.81 40.30 25.70 13.25 146.06

Miles of alleys paved 60.53 63.30 123.83

Total miles of paved/stabilized 133.04 41.84 25.70 79.71 0.00 280.29

PM-10 reductions (tons/year) 22.36 106.88 116.28 112.13 198.09

Pinal County

Miles of roads paved 15.22 2.30 1.53 1.95 21.00

PM-10 reductions (tons/year) 0.00 100.02 129.84 143.04 172.91

IV - 10
Jurisdiction 2008 2009 2010 2011 2012

Total Miles

Paved/Stabilized

Queen Creek

Miles of roads stabilized 1.00 1.00

PM-10 reductions (tons/year) 0.00 2.34 0.00 0.00 0.00

Scottsdale

Miles of roads stabilized 16.68 16.80 17.36 12.02 62.86

Miles of alleys stabilized 36.00 16.00 80.00 85.00 217.00

Total miles of paved/stabilized 52.68 32.80 97.36 97.02 279.86

PM-10 reductions (tons/year) 297.99 285.85 316.62 291.26 0.00

Surprise

Miles of roads paved 0.30 1.10 1.40

Miles of roads stabilized 3.49 6.30 4.00 13.79

Miles of alleys stabilized 3.69 3.69

Total miles of paved/stabilized 3.49 10.29 5.10 0.00 0.00 18.88

PM-10 reductions (tons/year) 16.69 30.05 337.46 738.60 740.63

Tempe

Miles of roads stabilized 0.15 0.15

Miles of alleys stabilized 34.20 19.02 2.80 3.10 59.12

Total miles of paved/stabilized 34.35 19.02 2.80 3.10 59.27

PM-10 reductions (tons/year) 12.20 6.37 0.94 1.04 0.00

Tolleson

Miles of alleys stabilized 0.50 0.75 1.25

PM-10 reductions (tons/year) 0.17 0.25 0.00 0.00 0.00

Youngtown

Miles of roads stabilized 0.08 0.08

Miles of alleys paved 3.10 3.70 6.80

Miles of alleys stabilized 6.80 6.80

Total miles of paved/stabilized 9.90 3.78 0.00 0.00 0.00 13.68

PM-10 reductions (tons/year) 16.35 11.50 11.12 11.12 11.15

Total Miles 2008 2009 2010 2011 2008-2011

Miles of dirt roads paved 40.99 18.43 7.70 16.09 83.21

Miles of dirt roads stabilized 39.22 38.80 36.20 30.53 144.75

Miles of dirt alleys paved 65.92 4.02 0.45 63.30 133.69

Miles of dirt alleys stabilized 164.06 106.36 124.10 106.14 500.66

Total miles paved/stabilized 310.19 167.61 168.45 216.06 862.31

Total PM-10 Emissions Reduced (Tons/Year)

2008 2009 2010 2011 2012

Projects that paved or stabilized public

dirt roads and alleys 461.30 1,351.81 2,124.38 2,662.09 2,625.41

IV - 11
PAVING AND STABILIZING UNPAVED SHOULDERS

In September 2011, MAG contacted its member agencies to request detailed information

on paving and stabilization of unpaved shoulder projects that had been implemented in

2008- September 2011. The information collected included the location of the projects, the

year of completion, the length in curb miles, average daily traffic on the adjacent road,

whether the unpaved surface was stabilized prior to paving, whether curb and gutter was

also constructed and the funding source. This section describes the shoulder paving and

stabilization projects that were completed in 2008 through 2011 and the associated PM-10

emission reductions. The emission rates for unpaved shoulders are described in the CMAQ

Methodologies (MAG, 2011). 

The emission reductions associated with paving an unpaved shoulder without curb and

gutter are 0.29 grams per VMT on low traffic arterials, 0.20 grams per VMT on high traffic

arterials and 0.49 grams per VMT in the Salt River Area. If adding curb and gutter, the

emission rates are 0.38 grams per VMT for low traffic arterials, 0.27 grams per VMT for

high traffic arterials, and 0.66 grams per VMT in the Salt River Area. These emission rates

are multiplied by the estimated VMT on the road adjacent to the paving or stabilization

project. If the shoulders were stabilized prior to paving, the benefit is reduced by 50

percent. Credit for paving shoulders is taken in the years after the project was completed. 

The benefit of projects that stabilize unpaved shoulders is calculated using the paving

emission factors, but the benefit is reduced by 50 percent. Credit for stabilization projects

is taken only in the year the project was completed. 

Table IV-4 shows the curb miles and PM-10 benefits of paving and stabilizing unpaved

shoulders in the PM-10 nonattainment area by jurisdiction. A summary of the paving and

stabilization project mileage and PM-10 reductions is shown at the bottom of the table. 

Seventeen cities and towns, Maricopa County and ADOT reported information on paving

and stabilization projects completed in 2008-September 2011. During this period, 232.73

miles of unpaved shoulders and 19.26 miles of curb and gutter were paved. Another

906.32 miles of unpaved shoulders were stabilized. The total PM-10 emissions reduced

by the paving and stabilization of unpaved shoulders is 150.01 tons in 2012. 

It is important to note that no credit is taken for shoulder stabilization projects in 2012,

because these projects have not yet been implemented. It is clear, however, based on the

projects implemented in 2008-2011, that some jurisdictions will be stabilizing unpaved

shoulders in 2012 and therefore, the reduction credit calculated for paving unpaved

shoulders in 2012 is conservative.

REDUCED SPEED LIMITS ON UNPAVED ROADS AND ALLEYS

In September 2011, MAG contacted its member agencies to request detailed information

on reduced speed limits on unpaved roads and alleys that had been implemented in 2008-

September 2011. The information collected included the location of the projects, the year 

IV - 12
Table IV-4

PM-10 Reductions for Paving and Stabilizing Unpaved Shoulders

Jurisdiction 2008 2009 2010 2011 2012

Total Curb Miles

Paved/Stabilized

ADOT

Curb miles of shoulders paved 49.47 77.00 126.47

Curb miles of curb and gutter paved 19.26 19.26

Total miles paved & stabilized 68.73 77.00 145.73

PM-10 reductions (tons/year) 0.00 21.03 49.84 49.84 49.98

Apache Junction

Curb miles of shoulders stabilized 6.26 6.26 1.50 14.02

PM-10 reductions (tons/year) 0.77 0.77 0.14 0.00 0.00

Avondale

Curb miles of shoulders stabilized 6.05 6.05 12.10

PM-10 reductions (tons/year) 0.00 1.31 1.31 0.00 0.00

Buckeye

Curb miles of shoulders paved 4.65 1.16 9.30 15.11

Curb miles of shoulders stabilized 8.10 8.10

Total miles paved & stabilized 4.65 1.16 17.40 23.21

PM-10 reductions (tons/year) 0.00 0.77 2.14 3.36 3.37

Chandler

Curb miles of shoulders paved 3.30 3.30

Curb miles of shoulders stabilized 7.30 2.00 9.30

Total miles paved & stabilized 7.30 2.00 3.30 0.00 0.00 12.60

PM-10 reductions (tons/year) 8.22 2.25 0.00 7.41 7.43

El Mirage

Curb miles of shoulders paved 1.62 1.62

Curb miles of shoulders stabilized 16.00 0.25 16.25

Total miles paved & stabilized 16.00 0.25 1.62 17.87

PM-10 reductions (tons/year) 5.52 0.03 0.00 0.63 0.63

Gilbert

Curb miles of shoulders stabilized 15.88 15.88 15.88 15.88 63.52

PM-10 reductions (tons/year) 6.25 6.23 6.23 6.23 0.00

Glendale

Curb miles of shoulders paved 2.46 2.46

Curb miles of shoulders stabilized 6.40 6.61 13.01

Total miles paved & stabilized 2.46 0.00 6.40 6.61 0.00 15.48

PM-10 reductions (tons/year) 0.00 3.35 5.13 6.65 3.36

Guadalupe

Curb miles of shoulders paved 1.60 1.60 1.60 0.50 5.30

PM-10 reductions (tons/year) 0.00 0.45 0.91 1.36 1.51

IV - 13
Jurisdiction 2008 2009 2010 2011 2012

Total Curb Miles

Paved/Stabilized

Maricopa County

Curb miles of shoulders paved 13.17 13.17

PM-10 reductions (tons/year) 0.00 0.00 0.00 14.89 14.93

Mesa

Curb miles of shoulders paved 5.31 23.70 12.11 41.12

Curb miles of shoulders stabilized 0.75 0.75

Total miles paved & stabilized 5.31 23.70 12.86 0.00 0.00 41.87

PM-10 reductions (tons/year) 0.00 41.01 41.35 41.01 41.12

Peoria

Curb miles of shoulders stabilized 43.13 43.13 43.13 43.13 172.52

PM-10 reductions (tons/year) 8.96 8.94 8.94 8.94 0.00

Phoenix

Curb miles of shoulders paved 3.85 3.56 1.29 3.90 12.60

PM-10 reductions (tons/year) 0.00 0.97 1.99 2.35 3.21

Queen Creek

Curb miles of shoulders paved 1.85 1.85

Curb miles of shoulders stabilized 9.03 25.02 26.94 60.99

Total miles paved & stabilized 10.88 25.02 26.94 0.00 0.00 62.84

PM-10 reductions (tons/year) 6.48 18.44 17.32 0.53 0.53

Scottsdale

Curb miles of shoulders paved 4.00 2.00 6.00

Curb miles of shoulders stabilized 131.60 132.20 123.80 134.60 522.20

Total miles paved & stabilized 131.60 132.20 127.80 136.60 0.00 528.20

PM-10 reductions (tons/year) 136.47 135.48 128.65 147.83 21.64

Surprise

Curb miles of shoulders paved 2.67 2.67

Curb miles of shoulders stabilized 2.82 2.74 3.50 9.06

Total miles paved & stabilized 2.82 2.74 6.17 0.00 0.00 11.73

PM-10 reductions (tons/year) 0.36 0.28 0.52 2.08 2.09

Tempe

Curb miles of shoulders paved 0.06 0.06

Curb miles of shoulders stabilized 0.50 0.50

Total miles paved & stabilized 0.50 0.06 0.00 0.00 0.00 0.56

PM-10 reductions (tons/year) 0.06 0.00 0.01 0.01 0.01

Tolleson

Curb miles of shoulders paved 1.00 1.00

PM-10 reductions (tons/year) 0.00 0.22 0.22 0.22 0.22

IV - 14
Jurisdiction 2008 2009 2010 2011 2012

Total Curb Miles

Paved/Stabilized

Youngtown

Curb miles of shoulders stabilized 2.00 2.00 4.00

PM-10 reductions (tons/year) 0.22 0.22 0.00 0.00 0.00

Total Curb Miles 2008 2009 2010 2011 2008-2011

Curb miles of dirt shoulders paved 70.19 107.08 49.06 6.40 232.73

Curb miles of curb and gutter paved 19.26 0.00 0.00 0.00 19.26

Curb miles of dirt shoulders stabilized 234.52 235.53 236.06 200.22 906.32

Total curb miles paved & stabilized 323.97 342.61 285.11 206.62 1,158.31

Total PM-10 Emissions Reduced (Tons/Year)

2008 2009 2010 2011 2012

Pave or stabilize unpaved shoulders 173.31 241.75 264.70 293.34 150.01

IV - 15
of completion, the length of the roads impacted by the reduced speed limits, and the

average daily traffic on the unpaved road or alley. This section describes the reduced

speed limit projects that were completed in 2008 through 2011 and the associated PM-10

emission reductions. Table IV-5 provides the miles of roads and alleys for which speed

limits were reduced and the associated PM-10 reductions by jurisdiction.

Two towns and Maricopa County posted lower speed limits on unpaved roads and alleys

in 2008-2009. Buckeye posted 15 mph signs on 5.4 miles of unpaved roads; the average

speed prior to posting was assumed to be 25 mph, which is the ADOT Department of Motor

Vehicles speed limit if there are no signs posted. Youngtown posted 10 mph speed limits

on 6.8 miles of unpaved alleys; it was assumed that the average speed prior to posting was

15 mph. Maricopa County posted 15 mph speed limits on 6.42 miles and 25 mph speed

limits on 1.74 miles of unpaved roads. It was assumed that the speeds on these County

roads decreased by 10 mph as a result of the lower speed limits. It was also assumed that

compliance with all of these new speed limits would be 70 percent. The unpaved road and

alley emission rates used in calculating credit for these lower speed limits are consistent

with those used in the 2008 PEI.

OVERLAYS WITH RUBBERIZED ASPHALT

In September 2011, MAG contacted the Arizona Department of Transportation (ADOT) to

request detailed information on the state highways that had been overlaid with rubberized

asphalt in 2008-September 2011. The information collected included the year of

completion, route names, the start and end points, the number of lanes, and the average

traffic volume per lane. Table IV-6 shows the assumptions used to calculate the PM-10

reductions in tire wear emissions for the highways that were overlaid with rubberized

asphalt in 2008 by ADOT. The total PM-10 emission reductions associated with this project

are 2.61 tons in 2009-2012.

DEMONSTRATION THAT THE PM-10 REDUCTION PROJECTS IMPLEMENTED IN

2008-2011 MEET CONTINGENCY REQUIREMENTS

As shown in Table IV-1, the total PM-10 emissions reduction in 2012 due to implementation

of the projects described above is 3,439 tons. This reduction exceeds the contingency

target of 3,218 tons by 221 tons. Therefore, the emission reductions from the projects

described in this chapter meet the contingency requirements of the Clean Air Act. 

As discussed previously, no credit has been taken for unpaved road, alley and shoulder

stabilization projects in 2012, because these projects have not yet been implemented. It

is clear, however, based on the projects implemented in 2008-2011, that some jurisdictions

will be stabilizing unpaved roads, alleys and shoulders in 2012 and therefore, the

contingency reduction credit calculated for 2012 is conservative.

The projects that have been quantified for contingency credit are not required to meet the

five percent requirement, model attainment, or demonstrate reasonable further progress.

IV - 16
Table IV-5

PM-10 Reductions for Reduced Speed Limits on Unpaved Roads and Alleys

Jurisdiction 2008 2009 2010 2011 2012

Total

Miles

Buckeye

Miles of roads with lower speeds 2.50 2.90 5.40

PM-10 reductions (tons/year) 0.00 78.42 155.06 155.06 155.48

Maricopa County

Miles of roads with lower speeds 8.16 8.16

PM-10 reductions (tons/year) 0.00 0.00 5.91 5.91 5.93

Youngtown

Miles of alleys with lower speeds 6.80 6.80

PM-10 reductions (tons/year) 3.61 0.00 0.00 0.00 0.00

Total Miles Impacted 2008 2009 2010 2011 2008-2011

Miles of roads/alleys with lower speed limits 6.80 10.66 2.90 0.00 20.36

Total PM-10 Emissions Reduced (tons/year) 2008 2009 2010 2011 2012

Lower speed limits on unpaved roads/alleys 3.61 78.42 160.97 160.97 161.41

IV - 17
 Table IV-6

PM-10 Reductions for ADOT Overlays with Rubberized Asphalt

Avg # of

Lanes

Avg Vehicles

Per Lane

 Reduction*

(tons/lanemile/

year)

PM-10 reduct

Route Start End Miles 2008 2009 2

Interstate 10 Ray Road Wildhorse

Pass 

2.84 6.68 15,065 0.0301 0.57 

Interstate 17 Arizona

Canal

ThunderbirdRd

2.75 8.00 25,837 0.0517 1.14 

State Route 143 Interstate 10 Van Buren St 2.80 5.73 18,443 0.0369 0.59 State Route 202L,Red Mtn Freeway

Power Road University Dr 4.64 6.23 5,363 0.0107 0.31 

Totals 13.03 0.00 2.61 *ADOT indicated in the MAG 2007 Five Percent Plan that an average of 17,000 vehicles per lane result in a PM-10 emissitons/lanemile/year for rubberized asphalt overlays

IV - 18
In addition, these projects will not hasten attainment. As discussed in Chapter V, the

earliest attainment date that can be demonstrated via modeling is December 31, 2012. 

This chapter demonstrates that PM-10 emissions will be reduced by 3,439 tons more than

the reductions achieved by measures used to show progress and model attainment. The

contingency projects implemented in 2008-2011 are assisting in producing the three years

of clean data necessary to attain the standard at all monitors by December 31, 2012. 

PM-10 EMISSION REDUCTIONS DUE TO ALL MEASURES AND PROJECTS IN THE

FIVE PERCENT PLAN

Table IV-7 shows the PM-10 emissions for 2008-2012 by source category after increased

rule effectiveness and contingency reductions are applied. The total reduction attributable

to the rule effectiveness increases and contingency projects in the MAG 2012 Five Percent

is 9,982 tons in 2012. This represents a 17 percent reduction, relative to 2007 emissions. 

Total PM-10 emissions with all measures and contingency projects decline by 19,527 tons

or 33 percent between 2007 and 2012.

IV - 19
Table IV-7

2008-2012 PM-10 Emissions with All Plan Measures and Contingency Projects

Source Category 2008 2009 2010 2011 2012

POINT 150 133 127 128 135

AREA

Fuel combustion 1,301 1,307 1,311 1,316 1,328

Commercial cooking 993 998 1,001 1,005 1,014

Construction (includes windblown dust) 8,355 5,333 4,139 4,014 4,073

Tilling, harvesting and cotton ginning 893 893 893 893 893

Travel on unpaved farm roads 731 731 731 731 731

Livestock 261 261 261 261 261

Travel on unpaved parking lots 2,422 2,434 2,441 2,451 2,473

Offroad recreational vehicles 2,180 2,191 2,198 2,206 2,226

Leaf blowers 895 899 902 906 914

Windblown agriculture 448 448 448 448 448

Other windblown sources 3,938 3,788 3,788 3,788 3,639

Fires 497 497 497 497 497

Mining/quarrying (includes windblown dust) 476 401 355 356 369

Travel on industrial paved/unpaved roads 472 382 331 333 351

Other industrial sources 976 865 828 832 877

NONROAD

Aircraft 184 152 142 143 146

Airport ground support equipment 27 23 21 20 20

Locomotives 34 34 34 34 34

Other nonroad equipment 1,683 1,661 1,641 1,595 1,513

ONROAD

Exhaust 2,836 2,647 2,371 1,843 1,407

Tire wear 256 254 255 255 259

Brake wear 758 767 771 773 787

Paved roads 7,922 7,857 7,578 7,534 7,772

Unpaved roads and alleys 9,847 8,854 7,999 7,461 7,525

Totals 48,534 43,810 41,062 39,823 39,691

Total PM-10 Emissions Reduction 2007-2012: 19,527 tons, 33.0%

IV - 20
REFERENCES

EPA, 1993. Early Implementation of Contingency Measures for Ozone and Carbon

Monoxide (CO) Nonattainment Areas. August 1993.

MAG, 2011. Methodologies for Evaluating Congestion Mitigation and Air Quality

Improvement Projects. Maricopa Association of Governments. September 30, 2011.

IV - 21
V. ATTAINMENT MODELING

INTRODUCTION

In order to show attainment with the 24-hour PM-10 National Ambient Air Quality Standard

for the Maricopa County PM-10 nonattainment area under high wind conditions, modeling

was performed for both the PM-10 nonattainment area and a subset of the nonattainment

area known as the Salt River area. The sections in this chapter of the TSD provide a

detailed discussion of the elements necessary to perform the attainment modeling and

demonstrate that attainment is met in 2012; specifically including:

! The reasons for choosing distance-weighted rollback as a conceptual model

for the attainment demonstration; 

! An analysis of the insights gained through operation of a short-term PM-10

temporary monitor saturation study; 

! The application of a PM-10 emissions source weighting factor based upon

distance from the exceeding monitor;

! An analysis of the non-anthropogenic low and high wind background PM-10

concentrations in the Maricopa County nonattainment area;

! The process for selecting design days;

! The development of low and high wind modeling domains;

! The creation of model-ready low and high wind emissions inventories;

! Application of the benefits of the control measures; and

! A demonstration of attainment in 2012.

An overview of the attainment modeling can be found in Chapter Five of the main plan

document.

V - 1
CONCEPTUAL MODEL

In December 2007, the Maricopa Association of Governments (MAG) submitted the “MAG

Five Percent Plan for PM-10 for the Maricopa County Nonattainment Area” (Five Percent

Plan) to the U.S. Environmental Protection Agency (EPA) in fulfillment of federal Clean Air

Act requirements after a failure to attain the 24-hour PM-10 ambient air quality standard

(standard) by the statutory deadline of December 31, 2006. The MAG 2007 Five Percent

Plan for PM-10 included fifty-three control measures that demonstrated PM-10 emissions

reductions of five percent per year and attainment of the PM-10 standard in 2010.

In 2008, there were a number of exceedances of the 24-hour PM-10 standard due to high

winds in the Maricopa County nonattainment area. EPA indicated that it did not concur with

four high wind exceptional events at the West 43rd Avenue monitor, which constituted a

violation. The region then did not have the three years of clean data needed for attainment. 

In September 2010, EPA published a notice to propose a partial approval and disapproval

of the MAG 2007 Five Percent Plan for PM-10. The two major reasons for the proposed

disapproval were inaccuracies in the 2005 baseline emissions inventory and EPA’s

nonconcurrence with the four high wind exceptional events.

In January 2011, the Arizona Department of Environmental Quality (ADEQ) withdrew the

MAG 2007 Five Percent Plan for PM-10 to address the technical approvability issues

identified by EPA, and to include new information such as the new EPA equation for paved

road dust emissions. EPA has indicated that the revised plan needs to show how high wind

emissions will be adequately mitigated. 

Presented below is a review of the issues considered in assessing available modeling

concepts and the steps leading to the selection of distance-weighted rollback as the

conceptual model.

Modeling Domain

Due to the uniform pattern and direction of wind flows upwind of the Salt River monitors

during high wind events in the Spring, the use of modeling domains extending along wind

back-trajectories from these monitors focuses the areal extent of these modeling domains

to the areas of significant emission contribution. Past analyses of back-trajectories related

to exceptional event evaluations in the Spring have shown that many are from the

west/southwest and lie along the Salt River channel due to prevailing synoptic wind fields

and the topographic influence of the Estrella Mountains lying directly south and running

parallel to the river channel. Furthermore, past modeling analyses indicate that the lands

significantly contributing to elevated PM-10 concentrations recorded at a monitoring site

lie generally within a mile of either side of the back-trajectory path upwind of the monitor. 

Since the areal extent impacting monitors is largely a function of wind speed, it necessary

to divide selected design days into low and high wind hours. High wind hours need to

represent sources located along back trajectories and low wind hours need to represent

V - 2
sources within a modeling domain surrounding the selected monitoring site. A significant

amount of work was devoted to developing the Salt River area modeling domain in the

withdrawn Five Percent Plan which is employed to assess emissions impacting Salt River

monitors during low wind hours. As part of a regional demonstration of attainment, other

low wind modeling domains that represent similar distributions of land use around modeled

monitors are developed as necessary. The basis for distinguishing between low and high

wind hours is the 12 mph aerodynamic entrainment threshold (i.e., five-minute average)

established in the 2008 PM-10 Periodic Emissions Inventory (Appendix A, Exhibit 1). Both,

five-minute and hourly wind measurements at selected monitoring sites are available and

can screen to determine which hours are “high wind” hours. The remaining hours are

assumed to be “low wind” hours.

Modeling Inventory Development

The withdrawn Five Percent Plan expended considerable resources in collecting sourcespecific activity data (e.g., traffic counts, aggregate facility operating records, silt

measurements, etc.) within the modeling domain to provide an accurate representation of

emissions on the days selected for modeling. The focus of that effort, however, was on

characterizing emissions under low wind stagnant conditions. While emission estimates

were also prepared for a high wind day, the model performance resulting from that

inventory was considerably poorer than for the inventories developed for days with stagnant

conditions. Given that experience, it suggests a different emissions inventory methodology

is needed (i.e., one along the lines of quantifying upwind emissions along a back trajectory

during high wind hours and low wind emissions within a modeling domain surrounding the

selected monitoring site). Due to the limited contribution of low wind hours to the 24-

average values recorded on high wind days it is suggested that design-day specific low

wind inventories are not necessary to characterize low wind hour emissions within the Salt

River modeling domain and the PM-10 nonattainment area as a whole. Instead, it is

planned that existing annual emission estimates be employed through allocation of those

emissions to the land uses within each of the modeling domains. 

For high wind hours, the methodology employed in the windblown dust emissions inventory

developed for the 2008 PM-10 Periodic Emissions Inventory is used to quantify fugitive dust

emissions at upwind sources located along back-trajectory domains from each of the

modeled monitors. One question that had not been previously researched, was how far

back along a back-trajectory line the modeling domain should extend. Insight into this

question is provided in the discussion below of data collected at a temporary monitor

upwind of the West 43rd Ave. monitoring site. 

Temporary Monitoring Insights

An analysis of matched pair measurements between the West 43rd Ave. long-term monitor

and 43rd Ave. & Broadway temporary monitor (a distance of 0.42 miles) was prepared for

the period between April 2010 and March 2011. The data were organized into five-degree

increments so concentration differences could be computed as a function of wind direction

V - 3
and wind speed. Measurements were organized into three categories of wind speed: 2-6

mph, 6-12 mph, and >12 mph (both monitors had to have wind speeds falling into these

categories to be included in the analysis). Tabulations of the results for these monitors and

other temporary monitors are presented in the subsequent section entitled Temporary

Monitoring Insights. The results for these monitors show that at 240°, the angular direction

traveling southwest from the West 43rd Ave. monitor to the West 43rd Ave. & Broadway

temporary monitor, average concentrations at the West 43rd monitor are consistently higher

than at the temporary site:

! At 2-6 mph, the difference (West 43rd - West 43rd & Broadway/West 43rd) is

13.5% (6.38 μg/m3);

! At 6-12 mph, the difference is 9% (3.2 μg/m3

); and

! At >12 mph, the difference is 37.3% (39.78 μg/m3

)

The >12 mph differences increase as the angular direction increases from 240° - 290°,

suggesting that fugitive dust from land located between those sites disproportionately

impacted concentrations at the West 43rd Ave. monitoring site (particularly since emissions

impacting the monitor at that hour are coming from a minimum distance of 12 miles and the

distance between the monitors is 0.42 miles). This finding suggests that that any modeling

analysis prepared to support an attainment demonstration needs to account for the

distance between the location where fugitive dust is emitted and the monitoring site

impacted during high wind conditions (either through dispersion/deposition or some

weighting function).

Available Modeling Concepts

Simple Rollback – Simple rollback analysis provides the least rigorous approach to

determining the levels of emission control needed to reduce ambient PM-10 concentrations. 

A fundamental assumption underlying this method is that pollutant concentrations are

directly proportional to total emissions over the area of interest. This assumption acquires

some validity if emissions from significant source categories are uniformly distributed

throughout the modeling domain, and if control measures will reduce emissions equally

from each parcel in a particular source category. The benefits of using simple rollback

include a quick turnaround in computing emission reductions necessary to meet a desired

air quality improvement goal and the need for very limited emission inventory data to

complete the calculation. The drawbacks of using this approach include the loss of

accuracy in forecasting air quality improvements if sources are not uniformly distributed and

if control measures produce varying benefits on a parcel-by-parcel basis. Simple rollback

can be used with some success in modeling over microscale domains, but loses accuracy

as the modeling domain grows because of the effects of particle dispersion and deposition

over longer travel distances. Additionally, the microscale inventories surrounding each PM10 monitoring site are different, and one microscale inventory cannot be used to assess

inventory/air quality relationships at another site. Demonstrating that a control strategy is

V - 4
effective at all sites recording exceedances requires the development of separate microinventories for each monitoring site. This approach would also suffer accuracy losses if the

modeling domains extended more than about one-half mile from the monitoring site.

Weighted Rollback – A weighted rollback approach applies a distance reduction factor to

emissions of each source in the modeling domain. The reduction factor is calculated on

the basis of the distance between each source and the impacted monitoring site. This

method requires the separate analysis of distance reduction factors in addition to the

development of modeling domain emission inventories upwind of each impacted monitoring

site. The selection of a mathematical form for the calculation of distance reduction factors,

ranging from 1/distance to involved equation forms based on hourly meteorological data,

requires testing to refine. Coordinates of the centroid of each parcel of land within each

back-trajectory swath would need to be extracted from land use GIS files to facilitate the

calculation of parcel-specific weighting factors. The benefits of using this method also

include a relatively quick turnaround in computing emission reductions and, hence, air

quality improvements after inventory data are compiled and distance reduction factors are

computed. This approach also takes advantage of the limited-term saturation monitoring

data collected in 2010 and early 2011 to inform the calculation of distance reduction factors

at this site. 

Principle Component Analysis – Principle Component Analysis (PCA) is a multivariate

statistical technique that uses eigenvectors to represent varied inter-relationships present

in datasets. The latent root regression form extracts relationships among variables that

include a dependent variable (here, PM-10) and its predictors (e.g., wind speed, wind

direction, soil moisture levels, emissions). PCA is an attractive alternative to photochemical

and dispersion modeling when performance is poor due to problems with secondary

chemistry and/or meteorological modeling. PCA also provides a framework for assessing

the probability of attainment by contrasting meteorological conditions on design day(s)

relative to an extended historical record. The downside of the methodology is that it

requires assembly of relevant metrics for a long-term, multi-year meteorological record and

preparation of an emissions inventory over multiple years so that vectors representing the

bulk of the variance in the assembled dataset can be extracted. 

AERMOD – The use of dispersion models like AERMOD to quantify the relationship

between emissions and air quality can increase the accuracy of the reported results. 

Because of the complexities of the mathematical algorithms coded into the models to

quantify a number of dispersion components, the output of dispersion models like

AERMOD shows less linearity between emission strength and ambient pollutant

concentration than is inherent in rollback models. These complexities require detailed

assessments of the combinations of control measures converging to a solution that attains

air quality targets and minimizes instabilities in the economies of regulated sources. Some

sophisticated dispersion models, like ISCST3, contain particle deposition algorithms that

can be toggled to simulate this ambient removal mechanism. AERMOD does not contain

this capability, which is important in the modeling of windblown PM-10 emissions. An

additional concern is that AERMOD provides no carryover of entrained emissions from one

V - 5
hour to the next, which can lead to underestimates of concentrations under both stagnant

and high wind conditions.

Conclusion

Since high wind AERMOD model performance was poor in the withdrawn Five Percent

Plan, a weighted rollback approach was chosen to quantify the benefits of adopted controls

on individual low and high wind hour concentrations for both the Salt River area domain

and the regional nonattainment area demonstration. The 12 mph five-minute wind speed

threshold was chosen to distinguish between low and high wind hours on selected design

day(s). High wind hour emissions along the back trajectories are initially calculated based

upon land use type at 2007 base levels and then calculated again with the benefits of the

control measures through 2012 as identified in the new Five Percent Plan. The difference

in high wind emissions will provide the expected reduction benefit of the controls included

in the new Five Percent Plan. The aggregate weighted benefit computed for each high

wind hour should be applied to the corresponding high wind hour recorded concentration. 

Since there have been no stagnation exceedances of the PM-10 standard since 2007, it

is assumed that control measures implemented since 2007 have been successful in

eliminating exceedances during stagnant conditions. The successful elimination of

stagnation exceedances dictate that new low wind microscale, design day-specific

inventories are not needed. As such, existing annual low wind emissions are allocated by

land use in each of the low wind modeling domains as necessary. The 24-hour average

of benefit-adjusted low and high wind concentrations in 2012 are lastly contrasted with the

ambient 24-hour PM-10 standard to demonstrate attainment.

V - 6
TEMPORARY MONITOR INSIGHTS

In an effort to better understand source contributions impacting the West 43rd Ave

monitoring site during high wind events, Maricopa County, with support from the Arizona

Department of Environmental Quality (ADEQ) and the Maricopa Association of

Governments (MAG) deployed a series of temporary PM-10 monitors along the dominant

upwind trajectory in the spring of 2010. A total of five temporary monitors were deployed

at the following sites: Arlington, 115th Avenue, 67th Avenue, 51st Avenue, and West 43rd &

Broadway. The locations of the five temporary monitors and two nearby long-term

monitors, Buckeye and West 43rd Ave., are displayed in Figure V-1.

Figure V-1

Location of Temporary and Long-Term PM-10 Monitoring Sites

Monitor Placement

The location of each of the temporary monitors is identified below, along with a brief

description of the insight that it was expected to provide. 

West 43rd Avenue and Broadway (Temp #1) – The objective was to obtain measurements

at the western-most edge of the industrialized area located between the West 43rd Ave.

monitor and the river bed (roughly 0.4 miles west of the monitor). Differences between

monitored values at this location and the West 43rd Ave monitor will provide a basis to

assess contributions coming from nearby sources when the wind is from the

west/southwest.

V - 7
51st Avenue and W. Roeser Road (Temp #2) – The goal was to locate monitors on the

eastern side of 51st Ave. Differences between measurements at this site and Temp #1

would provide insight into contributions from aggregate facilities located between 51st Ave.

and 43rd Ave (a distance of roughly 1 mile). 

67th Avenue and Southern Avenue (Temp #3) – The goal was to locate monitors on the

eastern side of 67th Ave. between the river bed and Southern Ave. Differences between

measurements at this site and Temp #2 would provide insight into emissions from facilities

located within the 2 mile area located between 67th Ave. and 51st Ave.

115th Avenue – South side of PIR Bridge (Temp #4) – The purpose of this site was to obtain

information on particulate mass being transported by drainage flow down the Agua Fria

River during morning commutes. Concern had been expressed that drainage mass

accumulates on the river bed and surrounding area over time and is subsequently

reentrained under high wind conditions and impacting the West 43rd Ave. monitor. This

location also has the advantage of providing a rough mid-point measurement of PM-10

concentrations between the Buckeye and West 43rd Ave. monitors (it is located roughly 10

miles southwest of the West 43rd Ave. monitor). 

Arlington School (Temp #5) – The 5% Plan relied on measurements collected at Organ

Pipe National Monument to obtain estimates of background concentrations being

transported off the desert. The goal was to place a monitor beyond the western boundary

of agricultural fields located to the west of the Buckeye monitor to gain a true measurement

of background concentrations being transported off the desert into the Salt River area. 

Initially, it was thought that ADEQ could utilize the former monitoring site at Palo Verde;

subsequent investigation, however, determined this site was not available. 

Analysis

Presented below are comparisons of pairs of measurements collected between the fixed

and temporary sites moving west from the West 43rd Ave. monitor, highlighted in the box

displayed in Figure V-1. Comparisons between the Arlington and Buckeye sites are

presented in a separate section addressing Background Conditions. To aid the

comparison of site measurements, the data were organized into five-degree increments

so concentration differences could be computed as a function of wind direction and wind

speed. Comparisons between site measurements were adjusted to account for time it

takes air mass to travel between the two sites. This was done by lagging the upwind

measurement from the downwind measurement by the appropriate number of five-minute

intervals (the increment in which the data were collected) needed to account for the time

required for air mass to traverse the distance between the two sites along the angular

increment between the two sites. Thus, if the angle between the two sites is 260 degrees,

the average wind speed computed for that increment was used to adjust all of the angular

increments between 180 and 360 degrees. The reason is that the most accurate

comparison is along that angle connecting the two sites. Comparisons at other

increments reflect the impact of sources not located directly along the line/angle between

V - 8
the two sites. As the difference between the angular increment and the angle between the

two sites grows, the effects of these sources and dispersion become greater. Similarly,

as the distance between the two sites grows, the effects of nonaligned sources,

dispersion, and deposition continue to grow and the comparisons provide less insight. 

Fortunately, the sites are located to the southwest of the West 43rd Avenue monitor, which

is the dominant direction for high winds impacting that site. Comparisons along the arc

between 230 to 290 degrees generally have the largest measurement count and provide

the most relevant insight for the analysis. To simplify the presentation, comparisons of

winds coming from the east (i.e., 0 to 175 degree increments) are not included for any of

the lagged data sets for each site pair and wind speed category. All tables are presented

at the end of this section for ease of review.

West 43rd Avenue versus West 43rd Avenue & Broadway (Temp #1) – An analysis of

matched pair measurements between the West 43rd Ave. long-term monitor and 43rd Ave.

& Broadway temporary monitor was prepared for the period between April 2010 and March

2011. The data were organized into five-degree increments so concentration differences

could be computed as a function of wind direction and wind speed. Since the distance

between the two sites is 0.4 miles, no lags were introduced into the data comparisons. 

With the comparisons all on a consistent time basis, results are presented for winds

coming from all directions not just the west. 

Measurements were organized into three categories of wind speed: 2-6 mph (Tables V-5

& V-6), 6-12 mph (Tables V-3 & V-4), and >12 mph (Tables V-1 & V-2). To ensure

matched pair comparisons, both monitors had to have wind speeds falling into these

categories to be included in the analysis. The results show that at 240 degrees, the

angular direction traveling southwest from the West 43rd Ave. monitor to the West 43rd Ave.

& Broadway temporary monitor, average concentrations at the West 43rd monitor are

consistently higher than at the temporary site:

! At 2-6 mph, the difference (West 43rd - West 43rd & Broadway/West 43rd) is

13.5% (6.38 μg/m3

);

! At 6-12 mph, the difference is 9% (3.2 μg/m3

); and

! At >12 mph, the difference is 37.3% (39.78 μg/m3

).

The >12 mph differences increase as the angular direction increases from 240 – 290

degrees, suggesting that fugitive dust from land located between those sites

disproportionately impacted concentrations at the West 43rd Ave. monitoring site

(particularly since emissions impacting the monitor at that hour are coming from a

minimum distance of 12 miles and the distance between the monitors is 0.4 miles). This

finding suggests that any modeling analysis prepared to support an attainment

demonstration needs to account for distance between the location where fugitive dust is

emitted and the monitoring site impacted during high wind conditions (either through

dispersion/deposition or some weighting function). 

V - 9
West 43rd Avenue & Broadway (Temp #1) versus 51st Avenue & W. Roeser Road (Temp

#2) – An analysis of matched pair measurements between these sites was also prepared

for the period between April 2010 and March 2011. Only the high wind category (>12

mph), was analyzed from this pair to get the insights of the emissions between these two

monitors. Low wind conditions (< 12 mph) were excluded because of the relatively long

distances of the sources to the West 43rd monitor and the great wind variability during low

wind conditions. To account for the time it takes wind to travel the 1-mile distance

between the two sites, the Temp #2 site measurement was lagged by five minutes relative

to the Temp 1 measurement (for winds coming from the west). Tabulations of the high

wind results are presented in Table V-7. The results show that at 250 degrees, the

angular direction when wind is traveling from the southwest from Temp #2 to Temp #1,

average concentrations at Temp #1 were consistently higher than at Temp #2:

! At >12 mph, 250 degrees, the difference is 33.8% (28.5 μg/m3

).

A similar relationship was observed between the two sites when the wind was coming from

a broader arc from southwest (200 to 270 degrees), average concentrations at Temp #1

were consistently higher than they were at Temp #2. Wind directions between 270 and

300 degrees produced the opposite relationship, with Temp #2 concentrations consistently

higher than Temp #1. This indicates that when the wind is coming from the southwest,

fugitive dust from disturbed land located between the two monitors is contributing to

elevated concentrations at West 43rd & Broadway and therefore impacting concentrations

recorded at the West 43rd Avenue monitoring site. It also suggests that there is

considerably less disturbed land located in the 270 and 300 degree arc between the two

sites. 

51st Avenue & W. Roeser Road (Temp #2) versus 67th Avenue & Southern Avenue (Temp

#3) – Similar to the previous analysis, comparisons between the April 2010 and March

2011 data set were prepared only for high wind conditions. The data were lagged by ten

minutes to account for the time required for air mass to transit the 2-mile distance between

the two sites (i.e., Temp #3 measurements were lagged 10 minutes relative to Temp #2

measurements). A summary of the comparisons for winds coming from the west is

presented in Table V-8. 

The results show that at 255 degrees, the angular direction traveling southwest from the

Temp 2 to Temp 3 monitor, average concentrations at the 51st Ave. monitor are lower

than at the 67th Ave monitor:

! At >12 mph, 255 degrees, the difference is -7.4% (-4.6 μg/m3

).

This pattern of higher upwind values is seen consistently in an arc ranging from 240 to 300

degrees. It is also opposite of the patterns seen in the previous site comparisons. This

suggests that upwind sources impacting the 67th Ave. monitor had a significantly greater

impact than sources located between the two sites had on the 51st Ave monitor. Another

factor to consider is that the greater distance between these sites also allows more

V - 10
time/distance for dispersion and deposition relative to the previous site comparisons. 

Given the limitations of the data, it is not possible to know which effect is stronger (i.e., the

influence of nearby upwind sources at both sites versus dispersion/deposition). 

Nevertheless, it suggests some form of distance weighting should be incorporated into the

modeling because the greatest impacts at the West 43rd Avenue monitor appear to be

coming from nearby upwind land. 

67th Avenue & Southern (Temp#3) versus 115th Avenue (Temp #4) – Similar to the

previous analysis, comparisons between the April 2010 and March 2011 data set were

only prepared for high wind conditions. The data were lagged by 25 minutes to account

for the time required for air mass to transit the 6-mile distance between the two sites (i.e.,

Temp #4 measurements were lagged 25 minutes relative to Temp #3 measurements). 

A summary of the comparisons for winds coming from the west is presented in Table V-9.

The results show that at 255 degrees, the angular direction traveling southwest from the

Temp 2 to Temp 3 monitor, average concentrations at the 51st Ave. monitor are

consistently lower than at the 67th Ave monitor:

! At >12 mph, 255 degrees, the difference is -48.0% (-33.1 μg/m3).

This pattern is consistent with that observed in the previous comparison between Temp

#2 and #3, but inconsistent with the pattern seen in the sites closer to the West 43rd

Avenue monitor. The differences observed at 255 degrees between Temp #3 and #4,

however, are not generally seen over the broader arc between 230 to 290 degrees. 

Generally, the pattern is the opposite—higher values are recorded at the 67th Avenue

monitor, suggesting land located between the two sites, but not directly along the angle

between them, is contributing to emissions impacting that site.

115th Avenue (Temp #4) versus Buckeye – Due to the 18-mile distance between the sites,

no comparisons were prepared. 

Summary

Analysis of data collected along a line of fixed and temporary PM-10 monitors located on

a southwest trajectory from the West 43rd Avenue monitor between April 2010 and March

2011 shows a pattern of elevated impacts from nearby lands. Similar impacts were

observed in comparisons between concentrations recorded at the next set of upwind sites. 

Subsequent site comparisons produced inconsistent and contradictory results, indicating

a lessening impact of lands located between the monitored pairs. These findings suggest

that lands with the greatest impacts on concentrations recorded at the West 43rd Avenue

site are nearby and diminish with distance. The trajectory modeling used to estimate

concentrations during high wind hours should incorporate a form of distance weighting or

dispersion to account for this effect.

V - 11
Table V-1

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

West 43rd Ave/Broadway and West 43rd Monitors When Winds Exceeded 

12 mph (0 - 175 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference

(μg/m3)

Difference

(Percent)

0 21 116.39 113.54 -2.85 -2.5%

5 40 80.27 89.04 8.77 9.8%

10 36 75.15 86.64 11.49 13.3%

15 38 52.07 41.29 -10.78 -26.1%

20 38 43.94 29.64 -14.31 -48.3%

25 38 58.74 27.68 -31.07 -112.3%

30 28 128.18 70.54 -57.64 -81.7%

35 11 167.49 72.14 -95.35 -132.2%

40 11 96.82 45.57 -51.25 -112.4%

45 8 122.26 50.31 -71.95 -143.0%

50 8 66.86 31.31 -35.55 -113.5%

55 1 94.40 47.90 -46.50 -97.1%

60 7 58.56 68.64 10.09 14.7%

65 8 52.56 40.15 -12.41 -30.9%

70 14 50.38 44.15 -6.23 -14.1%

75 27 50.50 46.56 -3.94 -8.5%

80 27 64.63 63.34 -1.29 -2.0%

85 25 56.80 50.55 -6.25 -12.4%

90 19 68.35 62.76 -5.58 -8.9%

95 22 49.96 50.95 0.98 1.9%

100 53 79.18 67.96 -11.22 -16.5%

105 35 141.95 101.19 -40.77 -40.3%

110 21 150.54 104.44 -46.10 -44.1%

115 12 22.78 40.67 17.89 44.0%

120 13 248.30 153.05 -95.25 -62.2%

125 15 166.12 87.01 -79.11 -90.9%

130 23 296.25 139.17 -157.07 -112.9%

135 15 418.20 318.69 -99.51 -31.2%

140 14 177.39 148.76 -28.62 -19.2%

145 12 123.76 118.34 -5.42 -4.6%

150 8 234.20 173.84 -60.36 -34.7%

155 6 796.67 1013.33 216.67 21.4%

160 8 529.34 601.58 72.24 12.0%

165 13 764.37 365.05 -399.32 -109.4%

170 4 273.75 398.73 124.98 31.3%

175 16 630.31 305.08 -325.24 -106.6%

V - 12
Table V-2

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

West 43rd Ave/Broadway and West 43rd Monitors When Winds Exceeded 

12 mph (180 - 360 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference

(μg/m3)

Difference

(Percent)

180 15 720.92 320.11 -400.81 -125.2%

185 3 310.43 156.47 -153.97 -98.4%

190 3 46.30 38.80 -7.50 -19.3%

195 2 105.20 94.25 -10.95 -11.6%

200 5 147.90 152.32 4.42 2.9%

205 3 646.00 774.00 128.00 16.5%

210 14 144.09 266.19 122.10 45.9%

215 16 373.00 419.85 46.85 11.2%

220 34 130.21 150.99 20.79 13.8%

225 32 66.88 109.71 42.82 39.0%

230 57 69.08 103.92 34.84 33.5%

235 104 63.30 102.79 39.50 38.4%

240 130 66.92 106.70 39.78 37.3%

245 158 88.30 132.58 44.29 33.4%

250 153 78.77 134.13 55.36 41.3%

255 182 68.66 129.96 61.30 47.2%

260 246 68.12 130.17 62.05 47.7%

265 271 48.46 91.98 43.53 47.3%

270 205 51.11 110.52 59.40 53.7%

275 141 64.33 124.81 60.48 48.5%

280 94 62.54 150.43 87.89 58.4%

285 51 62.39 124.07 61.68 49.7%

290 20 85.40 195.19 109.79 56.2%

295 24 51.48 74.85 23.37 31.2%

300 7 87.66 164.27 76.61 46.6%

305 8 45.71 46.89 1.18 2.5%

310 12 53.38 64.98 11.61 17.9%

315 15 52.79 53.25 0.45 0.9%

320 13 67.18 84.66 17.48 20.6%

325 8 62.76 56.28 -6.49 -11.5%

330 14 32.36 24.97 -7.39 -29.6%

335 23 57.46 49.74 -7.72 -15.5%

340 41 81.66 79.40 -2.26 -2.8%

345 49 49.45 43.17 -6.28 -14.6%

350 20 141.52 142.74 1.22 0.9%

355 30 126.71 105.82 -20.89 -19.7%

360 3 20.53 25.37 4.83 19.1%

V - 13
Table V-3

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

West 43rd Ave/Broadway and West 43rd Monitors When Winds Are Between

 6-12 mph (0 - 175 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference

(μg/m3)

Difference

(Percent)

0 61 20.32 16.66 -3.66 -22.0%

5 47 27.47 22.41 -5.06 -22.6%

10 45 31.10 26.73 -4.37 -16.3%

15 53 24.12 20.18 -3.94 -19.5%

20 55 20.65 20.55 -0.10 -0.5%

25 49 25.99 20.67 -5.33 -25.8%

30 41 29.32 22.95 -6.37 -27.8%

35 46 30.43 22.58 -7.85 -34.8%

40 57 27.96 20.81 -7.15 -34.3%

45 59 29.15 21.02 -8.13 -38.7%

50 66 28.94 21.84 -7.09 -32.5%

55 104 29.37 25.18 -4.19 -16.7%

60 141 36.94 29.59 -7.35 -24.8%

65 157 35.87 29.32 -6.55 -22.3%

70 264 37.52 59.90 22.38 37.4%

75 330 35.36 86.99 51.63 59.4%

80 279 36.85 64.04 27.18 42.5%

85 256 34.53 47.96 13.43 28.0%

90 319 30.11 31.37 1.26 4.0%

95 301 30.76 43.93 13.17 30.0%

100 275 32.54 34.14 1.59 4.7%

105 221 33.60 51.44 17.84 34.7%

110 206 26.63 24.19 -2.45 -10.1%

115 189 29.78 27.39 -2.39 -8.7%

120 156 30.39 26.72 -3.68 -13.8%

125 129 51.33 46.01 -5.33 -11.6%

130 125 30.62 24.80 -5.82 -23.5%

135 117 40.18 35.45 -4.73 -13.3%

140 110 39.70 39.48 -0.23 -0.6%

145 94 52.01 37.78 -14.24 -37.7%

150 109 56.90 59.36 2.47 4.2%

155 115 62.44 68.93 6.50 9.4%

160 105 49.32 41.58 -7.74 -18.6%

165 116 67.84 66.32 -1.53 -2.3%

170 82 50.22 66.74 16.52 24.8%

175 74 43.92 49.20 5.28 10.7%

V - 14
Table V-4

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

West 43rd Ave/Broadway and West 43rd Monitors When Winds are Between 

6-12 mph (180 - 360 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference

(μg/m3)

Difference

(Percent)

180 63 35.47 51.12 15.65 30.6%

185 57 26.91 27.85 0.95 3.4%

190 50 26.95 25.52 -1.43 -5.6%

195 74 28.78 38.80 10.02 25.8%

200 54 26.78 28.81 2.03 7.1%

205 65 28.55 30.41 1.86 6.1%

210 78 29.71 32.21 2.50 7.8%

215 93 25.50 36.73 11.23 30.6%

220 133 29.03 33.54 4.51 13.4%

225 219 32.26 34.84 2.58 7.4%

230 375 30.65 33.38 2.73 8.2%

235 389 30.89 34.32 3.43 10.0%

240 429 32.38 35.58 3.20 9.0%

245 514 33.45 42.23 8.78 20.8%

250 478 33.18 42.14 8.96 21.3%

255 629 35.81 41.11 5.30 12.9%

260 880 33.41 38.89 5.48 14.1%

265 951 32.05 37.10 5.05 13.6%

270 838 32.56 36.81 4.25 11.6%

275 763 32.53 37.56 5.03 13.4%

280 651 30.68 35.33 4.65 13.1%

285 509 27.87 30.98 3.11 10.0%

290 390 27.76 28.06 0.29 1.0%

295 228 27.45 29.60 2.15 7.3%

300 149 27.40 24.79 -2.62 -10.6%

305 96 32.92 27.19 -5.73 -21.1%

310 70 22.01 19.45 -2.56 -13.2%

315 60 35.80 26.73 -9.07 -33.9%

320 60 26.63 22.79 -3.84 -16.8%

325 58 23.16 22.42 -0.74 -3.3%

330 64 23.18 22.59 -0.58 -2.6%

335 50 23.22 16.96 -6.26 -36.9%

340 45 22.04 15.34 -6.70 -43.7%

345 55 25.49 15.47 -10.02 -64.8%

350 70 18.35 14.71 -3.64 -24.8%

355 64 20.18 19.90 -0.28 -1.4%

360 7 20.13 17.17 -2.96 -17.2%

V - 15
Table V-5

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

West 43rd Ave/Broadway and West 43rd Monitors When Winds are Greater 

Than 2 mph, but do not Exceed 6 mph

(0 - 175 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference*

(μg/m3)

Difference

(Percent)

0 518 46.53 40.66 -5.86 -14.4%

5 536 45.97 45.20 -0.77 -1.7%

10 601 52.61 50.22 -2.39 -4.8%

15 609 52.82 45.26 -7.56 -16.7%

20 638 47.23 43.22 -4.01 -9.3%

25 639 49.91 43.46 -6.45 -14.8%

30 636 51.64 42.89 -8.75 -20.4%

35 723 50.86 45.73 -5.13 -11.2%

40 708 48.95 41.29 -7.66 -18.6%

45 803 48.89 41.39 -7.50 -18.1%

50 859 46.98 41.00 -5.98 -14.6%

55 961 46.18 43.81 -2.38 -5.4%

60 1,113 47.28 43.02 -4.26 -9.9%

65 1,159 46.63 45.47 -1.16 -2.6%

70 1,373 44.75 50.10 5.35 10.7%

75 1,424 43.21 54.39 11.18 20.6%

80 1,316 43.92 49.60 5.68 11.5%

85 1,264 42.95 47.16 4.21 8.9%

90 1,341 40.62 42.41 1.78 4.2%

95 1,361 40.10 46.95 6.85 14.6%

100 1,340 41.59 40.95 -0.64 -1.6%

105 1,240 44.05 45.02 0.96 2.1%

110 1,078 43.69 40.22 -3.47 -8.6%

115 1,014 41.27 39.82 -1.45 -3.6%

120 978 45.21 42.08 -3.12 -7.4%

125 982 50.38 45.33 -5.04 -11.1%

130 958 52.45 48.14 -4.31 -8.9%

135 819 56.34 47.72 -8.63 -18.1%

140 874 54.13 47.03 -7.10 -15.1%

145 825 53.75 46.78 -6.97 -14.9%

150 796 55.61 48.67 -6.94 -14.3%

155 833 59.45 56.67 -2.78 -4.9%

160 790 57.46 52.65 -4.81 -9.1%

165 828 67.32 55.33 -11.99 -21.7%

170 841 52.88 51.87 -1.01 -1.9%

175 870 63.00 52.76 -10.24 -19.4%

V - 16
Table V-6

Angular Comparison of Matched Five-Minute PM-10 Concentrations

Collected at West 43rd Ave/Broadway and West 43rd Monitors

When Winds are Greater Than 2 mph, but do not Exceed 6 mph

(180 - 360 degrees)

WD Sector

(Degree)

Measurement

Count

43rd & Broadway

(μg/m3

)

West 43rd

(μg/m3)

Difference

(μg/m3)

Difference

(Percent)

180 913 63.96 53.33 -10.64 -19.9%

185 952 52.75 48.40 -4.35 -9.0%

190 954 50.78 50.93 0.15 0.3%

195 1,014 54.49 56.53 2.04 3.6%

200 1,007 52.77 58.15 5.38 9.3%

205 1,035 48.48 50.77 2.28 4.5%

210 1,080 47.35 51.14 3.79 7.4%

215 1,043 49.25 57.43 8.18 14.3%

220 1,126 43.43 47.65 4.23 8.9%

225 1,234 40.96 46.57 5.62 12.1%

230 1,479 38.28 45.15 6.87 15.2%

235 1,564 39.60 46.77 7.17 15.3%

240 1,733 40.90 47.28 6.38 13.5%

245 2,115 42.33 51.05 8.72 17.1%

250 2,154 43.65 56.51 12.86 22.8%

255 2,514 43.70 48.68 4.99 10.2%

260 2,795 44.17 51.20 7.04 13.7%

265 2,907 41.10 49.44 8.33 16.9%

270 2,755 41.13 45.52 4.39 9.7%

275 2,646 41.49 45.26 3.76 8.3%

280 2,515 39.15 42.85 3.70 8.6%

285 2,360 37.96 43.91 5.94 13.5%

290 1,964 37.29 35.66 -1.63 -4.6%

295 1,542 37.81 41.53 3.72 9.0%

300 1,243 39.00 41.53 2.53 6.1%

305 1,012 39.05 35.26 -3.79 -10.7%

310 929 40.86 36.68 -4.18 -11.4%

315 823 42.02 36.28 -5.74 -15.8%

320 769 39.93 38.25 -1.68 -4.4%

325 726 41.51 36.75 -4.76 -13.0%

330 639 43.14 38.31 -4.83 -12.6%

335 644 45.94 37.05 -8.89 -24.0%

340 587 45.38 40.66 -4.73 -11.6%

345 626 43.47 39.32 -4.15 -10.6%

350 624 47.85 40.69 -7.17 -17.6%

355 617 46.02 41.83 -4.19 -10.0%

360 52 37.66 41.61 3.95 9.5

V - 17
Table V-7

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

51st Avenue and West 43rd Ave/Broadway (lagged 5-minutes) Monitors When

Winds Exceeded 12 mph (180 - 355 degrees)

WD Sector

(Degree)

Measurement

Count

51st Avenue

 (μg/m3

)

43rd & Broadway

 (μg/m3)

Difference

(μg/m3)

Difference

(Percent)

180 9 274.6 839.6 565.0 67.3%

185 14 171.2 442.3 271.1 61.3%

190 3 27.4 83.1 55.7 67.0%

195 2 38.2 102.5 64.3 62.8%

200 NA NA NA NA NA

205 1 32.3 82.3 50.0 60.8%

210 4 34.3 154.3 120.0 77.8%

215 6 59.6 294.4 234.9 79.8%

220 8 182.0 278.3 96.4 34.6%

225 8 197.8 428.8 231.0 53.9%

230 14 219.7 298.2 78.5 26.3%

235 11 135.9 132.7 -3.3 -2.5%

240 18 38.8 78.8 39.9 50.7%

245 24 48.3 64.7 16.5 25.4%

250 34 55.7 84.2 28.5 33.8%

255 45 60.0 85.0 25.0 29.4%

260 52 37.7 57.5 19.8 34.4%

265 68 61.8 72.8 10.9 15.0%

270 76 49.4 62.2 12.8 20.5%

275 95 51.8 52.0 0.2 0.4%

280 90 43.9 39.8 -4.1 -10.3%

285 62 49.9 36.6 -13.4 -36.6%

290 35 47.0 29.7 -17.3 -58.2%

295 12 35.6 26.7 -8.8 -33.1%

300 6 49.8 46.8 -3.1 -6.6%

305 4 47.4 58.7 11.4 19.3%

310 5 37.5 51.7 14.2 27.5%

315 10 36.5 40.2 3.7 9.2%

320 13 60.9 73.3 12.4 16.9%

325 11 88.7 91.9 3.3 3.6%

330 4 21.0 21.8 0.8 3.6%

335 9 186.6 118.6 -68.0 -57.3%

340 40 50.2 55.9 5.7 10.2%

345 32 73.9 55.1 -18.8 -34.2%

350 15 111.3 86.0 -25.3 -29.4%

355 18 286.0 231.6 -54.4 -23.5%

V - 18
Table V-8

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

67th Avenue and 51st Avenue (lagged 10-minutes) Monitors When Winds 

Exceeded 12 mph (180 - 355 degrees)

WD Sector

(Degree)

Measurement

Count

67th Avenue

(μg/m3

)

51st Avenue

(μg/m3

)

Difference

(μg/m3)

Difference

(Percent)

180 10 517.4 181.8 -335.5 -184.5%

185 15 402.3 132.5 -269.8 -203.6%

190 6 64.5 71.0 6.5 9.2%

195 3 29.0 38.8 9.9 25.4%

200 NA NA NA NA NA

205 1 93.4 15.7 -77.7 -494.9%

210 1 221.5 320.7 99.2 30.9%

215 4 59.0 144.7 85.7 59.2%

220 8 106.2 164.9 58.7 35.6%

225 7 124.4 131.8 7.4 5.6%

230 13 154.1 226.6 72.5 32.0%

235 9 102.3 191.1 88.8 46.5%

240 25 55.7 37.9 -17.8 -46.9%

245 24 99.1 68.1 -31.1 -45.7%

250 37 88.3 53.5 -34.8 -65.1%

255 52 66.6 62.0 -4.6 -7.4%

260 63 60.3 45.2 -15.0 -33.2%

265 88 80.8 62.7 -18.2 -29.0%

270 93 72.3 55.0 -17.3 -31.4%

275 106 62.1 55.9 -6.2 -11.0%

280 102 53.6 62.1 8.5 13.7%

285 84 62.9 44.9 -18.0 -40.0%

290 58 148.4 73.2 -75.2 -102.7%

295 18 184.1 95.7 -88.5 -92.5%

300 13 114.0 51.8 -62.2 -120.0%

305 9 69.6 40.4 -29.2 -72.2%

310 18 70.9 71.7 0.8 1.1%

315 23 34.3 17.8 -16.4 -92.0%

320 16 97.7 49.3 -48.4 -98.3%

325 12 164.6 74.9 -89.8 -119.9%

330 3 27.6 20.9 -6.7 -32.3%

335 11 109.9 92.8 -17.1 -18.4%

340 36 47.5 40.7 -6.8 -16.7%

345 28 50.0 70.7 20.7 29.3%

350 16 85.3 84.4 -1.0 -1.1%

355 12 114.2 208.8 94.6 45.3%

V - 19
Table V-9

Angular Comparison of Five-Minute PM-10 Concentrations Collected at

115th Avenue and 67th Avenue (lagged 25-minutes) Monitors When Winds 

Exceeded 12 mph (180 - 355 degrees)

WD Sector

(Degree)

Measurement

Count

Avondale 

(μg/m3

)

67th Avenue

 (μg/m3)

Difference

(μg/m3)

Difference

(Percent)

180 NA NA NA NA NA

185 NA NA NA NA NA

190 2 59.7 499.5 439.9 88.1%

195 3 45.2 140.4 95.2 67.8%

200 3 27.7 303.8 276.1 90.9%

205 6 16.1 28.3 12.2 43.1%

210 11 56.3 58.4 2.1 3.6%

215 4 55.8 42.2 -13.6 -32.2%

220 11 125.2 164.7 39.5 24.0%

225 16 71.9 55.4 -16.5 -29.8%

230 22 68.5 158.7 90.2 56.8%

235 19 38.3 81.3 43.0 52.9%

240 33 50.8 56.5 5.8 10.2%

245 47 37.5 80.2 42.7 53.2%

250 84 42.4 113.7 71.3 62.7%

255 72 36.2 74.5 38.3 51.4%

260 87 102.3 69.1 -33.1 -48.0%

265 61 75.7 63.2 -12.5 -19.8%

270 86 38.2 44.2 5.9 13.4%

275 58 51.2 68.9 17.7 25.6%

280 56 50.5 88.3 37.8 42.8%

285 39 83.7 130.9 47.2 36.1%

290 30 112.5 177.6 65.1 36.7%

295 8 26.4 45.7 19.3 42.2%

300 4 25.9 81.5 55.7 68.3%

305 6 38.3 75.5 37.2 49.3%

310 2 25.4 66.0 40.7 61.6%

315 8 52.2 80.5 28.4 35.2%

320 25 36.8 66.3 29.5 44.5%

325 27 60.4 95.9 35.5 37.0%

330 5 140.7 35.9 -104.8 -291.8%

335 3 100.0 25.2 -74.8 -297.2%

340 19 25.9 37.6 11.7 31.1%

345 16 63.3 40.3 -23.0 -57.1%

350 9 173.8 79.1 -94.7 -119.6%

355 NA NA NA NA NA

V - 20
SOURCE WEIGHTING ANALYSIS

A modified rollback analysis is used to assess the benefits of controls to reduce windblown

dust emissions on disturbed soil areas. Although these benefits can be quantified in terms

of emissions, the corresponding reductions in ambient PM-10 concentrations at fixed

monitoring sites cannot be determined without additional analysis of the relationships

between emissions reductions and reductions in downwind concentrations. This

relationship is typically quantified through use of dispersion modeling, and dispersion

modeling is used in a screening mode here to inform modifications to the basic rollback

process.

Rollback analysis basically assumes a linear relationship between levels of pollutant

emissions and levels of resulting pollutant concentrations in downwind ambient air. Under

this approach, a fractional reduction in emissions is assumed to produce an equivalent

reduction in downwind ambient concentrations after backing out the contribution of

background air quality. In the case of entrained PM-10 generated by high wind events,

however, we know that two primary factors invalidate this principle of linearity: (1) the

settling and deposition from the airstream of entrained particulate with increasing time and

distance from the point of entrainment, and (2) the dispersion of particulate both laterally

and vertically within the airstream due to increased boundary layer turbulence at higher

wind speeds. Both of these phenomena cause PM-10 concentrations to drop dramatically

as air parcels holding these concentrations continue moving downwind from the soils

generating windblown dust during high wind events.

Fortunately, quantitative estimates of the impacts of these two phenomena can be derived

from the use of steady state, Gaussian-dispersion models configured to site-specific

conditions found in the Salt River area. One of these models, AERMOD, was used to

quantify source-receptor relationships in the previous version of the Maricopa Area Five

Percent Plan. For this reason, AERMOD was used to generate PM-10 concentrations

downwind of a hypothetical disturbed soil parcel producing windblown dust to assess the

rate at which the combination of particle deposition and dispersion reduced concentrations

at varying distances downwind of the source.

The hypothetical disturbed soil parcel was configured to represent such parcels typically

found in the windblown dust corridor straddling the Salt River. The area of the parcel was

specified to be 40 acres, representative of larger cultivated parcels in the area. The parcel

was assumed to be square with sides oriented north-south and east-west and measuring

401.54 meters each. The plume release height was set at 0.5 meters, the ambient

temperature at 297.9 °K (76.6 °F), and Monin-Obukhov lengths—relating to atmospheric

stability—were set at -304.2 meters. These ambient conditions were the same as those

that occurred at the W. 43rd monitoring station on the high wind hour of February 15,

2006, the single high wind day evaluated in the Technical Support Document to the initial

Five Percent Plan. The urban dispersion toggle was set to represent albedo from a

population center of 1.5 million. Both source and receptor elevations were set to zero to

generally represent the topographical gradient along the Salt River. The surface

V - 21
roughness was set at 0.04 meters based on Nickling and Gillies 1986 wind tunnel testing

in the Salt River area. The particle size ranges of loose soil particles entrained by high

wind conditions from this parcel were assumed to be the same as the size distribution

used in the initial Five Percent Plan modeling of high wind conditions. This distribution,

as adapted from ambient air monitoring conducted by T&B Systems in the Salt River area

in 2006, is shown in Table V-10.

Table V-10

Particle Characteristics

Diameter (micron) 1.229 3.263 4.949 6.802 8.724

Mass Fraction 0.189 0.27 0.231 0.206 0.105

Density (g/cm3

) 2.5 2.5 2.5 2.5 2.5

The emission rate for the 40-acre parcel was set at 1,000 pounds of PM-10 per hour, or

7.815x10-4 g/sec-m2, which is consistent with emission rates published in the 2008

Periodic Emissions Inventory for PM-10 (Appendix A, Exhibit 1).

Receptor sites were located at regular intervals downwind of the trailing edge of the area

source. Receptor spacing was set at 100 meters between 0 and 1,000 meters; at 200

meters between 1,000 and 3,000 meters; and then at 500 meters between 3,000 and

30,000 meters. All receptors were configured to lie on a radius pointing due east from the

source.

Meteorological conditions for this screening run included winds blowing from due west at

a series of elevated wind speeds. Hourly average wind velocities ranged from 12 to

24 mph in 1-mph increments.

The resulting hourly-average PM-10 concentrations reported by the AERMOD screening

run are shown in Appendix A. These results show concentrations varying by three orders

of magnitude over the downwind distance span of 0 to 30,000 meters. At the threshold

of high wind conditions, 12 mph, concentrations drop by a factor of 10 between 0 and 500

meters, between 500 and 2,800 meters, and between 2,800 and 30,000 meters. In other

words, emissions from sources proximate to or within 500 meters upwind of a monitoring

station will overwhelm the emission contributions of sources more than 500 meters

upwind.

The trends of modeling results were analyzed using the curve-fitting functions of Excel. 

In the first analytical series, plots of PM-10 concentrations vs. downwind distance were

mapped for the wind speeds of 12, 16, 20, and 24 mph. These plots are shown in

Figure V-2.

V - 22
Figure V-2

Relationship Between PM-10 Concentration and Source Distance at Different Wind S

12 MPH 16 MPH

20 MPH 24 MPH

V - 23
This progression of plots includes the best fit curve statistics for each AERMOD wind

speed. Because of the rapidity at which concentrations decline with increasing downwind

distance, a power curve was found to provide the best equation fit to these data. From

observation, the correlation coefficients (r2

) of these plots are very high—exceeding 0.96

in all cases. Similarly, the exponent of x in each best fit power curve hovers near -1.9,

suggesting that concentrations roughly decline with downwind distances on a 1/x2

 basis.

Further analysis of the modeling data, however, suggests a somewhat different picture. 

In each of the plots in Figure V-2, modeling results straddle the best fit curve in a

sinusoidal fashion. The first plot in Figure V-2, that of the 12 mph modeling results, was

disaggregated into separate sinusoid cycles to determine whether the power equation

exponent remained constant over each block of downwind receptors contained within a

cycle. The sinusoid cycles were chosen to encompass the receptor intervals of 0 to 1,000

meters; 1,000 to 3,000 meters; 3,000 to 15,000 meters; and 15,000 to 30,000 meters. The

resulting plots of PM-10 concentration vs. distance are presented in Figure V-3.

The plots in Figure V-3 show similarly high r2

 values, but the power exponents vary

substantially from -0.2 to -1.2. Also, the trend in power exponents is somewhat linear,

starting at the high end of -1.233 for receptors in the 0 to 1,000 meter range, and steadily

decreasing to -0.173 in the 15,000 to 30,000 meter range. These results point

dramatically to a concentration-distance relationship much closer to 1/x than 1/x2

,

especially in the critical zone of nearest receptors, from 0 to 1,000 meters, in which source

impacts significantly overwhelm the contributions of sources farther upwind of a receptor.

A similar, but less dramatic, result is seen when the modeling data are evaluated over

different portions of the right tail (i.e., toward increasing distances) of these plots in Figure

V-2. This analysis was conducted to determine the effect of removing the highest—and

most dominant—concentrations reported for near-downwind receptors from the analysis

in order to study that portion of the curve with the flatter gradient. In this analysis, power

equation curves were fitted to the distributions of PM-10 concentrations (1) over the full

range of receptors, (2) over the range of receptors equal to or greater than 500 meters

downwind of the source, (3) equal to or greater than 1,000 meters downwind, (4) equal to

or greater than 2,000 meters downwind, and (5) equal to or greater than 4,000 meters

downwind. The plots of these ranges are shown in Figure V-4.

The power curve statistics of plots in Figure V-4, like those in Figure V-3, show a declining

trend in negative power curve exponents with increasing distance, but also stable and very

high values of r2

 with increasing distance. Over the full range of receptors, the power

curve exponent is -1.803, again suggesting a roughly 1/x2

 relationship of PM-10

concentration with increasing downwind distance. Excluding the receptors within 500

meters of the source, however, causes the exponent to decline to -1.391. Removing

receptors within 1,000 meters, 2,000 meters, and 4,000 meters of the source causes the

power curve exponent to drop to -1.098, -0.825, and -0.504, respectively. These

exponents conversely suggest rough relationships between PM10 concentration and

distance of 1/x to 1/%x.

V - 24
Figure V-3

Relationship between PM-10 Concentration and Source Distance Increments at 12 mph W

12 MPH, 0-1000 M 12 MPH, 1000-3000 M

12 MPH, 3000-15000M 12 MPH, 15000-30000M

V - 25
Figure V-4

Relationship between PM-10 Concentration and Increasing Source Distances at 12 mph W

12 MPH, RECEPTORS > 0M 12 MPH, RECEPTORS > 5

12 MPH, RECEPTORS > 4000M

12 MPH, RECEPTORS > 1000M 12 MPH, RECEPTORS > 2

V - 26
Without question, receptors close to an upwind source will be much more dramatically

impacted by emissions from that source—emission rates being equal—than by similar

sources at increasing distances upwind of receptors. As a result, the power curve

exponents produced by the modeling of impacts in the near downwind field (0 to 1,000

meters) from this modeling analysis must be given greatest weight because of the

exponentially smaller impacts at receptors at greater downwind distances. The first curve

in Figure V-3 represents this receptor interval, and reports a power curve exponent of -

1.233. Because the remainder of the plots report exponents straddling this value, this

exponent represents the best singular value for the adjustment of downwind

concentrations with increasing distance. Also, because of the range of exponents reported

in these plots, an exponent of -1.0—equivalent to 1/x—is reasonably equivalent and

should be used to adjust windblown dust emission impacts with increasing downwind

distance in any modified rollback analysis in the Salt River area.

V - 27
BACKGROUND CONDITIONS

As discussed in the section addressing Temporary Monitoring Insights, Maricopa County,

with support from the Arizona Department of Environmental Quality (ADEQ) and the

Maricopa Association of Governments (MAG), deployed a series of temporary PM-10

monitors along the dominant upwind trajectory in the spring of 2010. A total of five

temporary monitors were deployed at the following sites: Arlington, 115th Avenue, 67th

Avenue, 51st Avenue, and West 43rd & Broadway. The locations of the five temporary

monitors and two nearby long-term monitors, Buckeye and West 43rd Avenue, are

displayed in Figure V-5.

Figure V-5

Location of Temporary and Long-Term PM-10 Monitoring Sites

The Arlington monitor is located west of Buckeye, beyond the edge of active

agricultural/irrigation land, both are highlighted in Figure 1. Data collected at the Arlington

site are intended to provide insight into non-anthropogenic concentrations coming in from

the desert. Despite its remote location, there are a number of sources located to the west

of the site that impact monitored concentrations—examples include the Palo Verde

Nuclear Generating Station, located three miles to the west/northwest; and the Mesquite

Power Plant, located three miles to the southwest. All of the remaining monitors are

directly impacted by emissions from upwind anthropogenic sources. Buckeye, located 11

miles east of Arlington, is the nearest monitor and is surrounded by agricultural lands. 

V - 28
Temporal Variations

Figures V-6 and V-7 compare wind speed, wind direction, and concentrations recorded at

the Arlington, Buckeye, and West 43rd Ave. monitoring sites for two separate episodes that

occurred on April 28-29, 2010, and May 22-23, 2010, respectively. 

Because wind speed and wind direction were not recorded at the Arlington site, wind

speed and wind direction data from the Buckeye and West 43rd monitors were used

instead. Both low and high wind speeds were observed during these high wind events. 

During low winds, the wind direction showed considerable variation, coming from all

directions; however, during high winds (wind speed > 12mph), constant west and

southwest wind flow was observed. These wind flows represent the frontal winds coming

from the west, the dominant direction for high wind events. During the high wind periods,

PM-10 spikes were observed at all three sites, with much higher PM10 concentrations

usually observed at the Buckeye and West 43rd monitors than at Arlington. Clearly, the

lower values recorded at Arlington are more representative of PM-10 background

concentrations transported by frontal winds coming in off the desert. Those values,

however, may be impacted by upwind anthropogenic sources—additional analysis of

concentrations as a function of wind direction is needed to assess their impacts. 

Data Analysis

Differences between matched pair measurements from Arlington and Buckeye were

calculated to provide insight into which upwind sources could be impacting Arlington

concentrations. The data were organized into five-degree increments so the concentration

differences could be computed as a function of wind direction and wind speed. Only

measurements with wind speeds greater than 12 mph were used to represent the high

wind events. The five-degree angular values for measurement count and average PM-10

and related standard deviations are presented in Table V-11. The angular direction

traveling from the Arlington monitor to the Buckeye monitor is about 265°. The results

show that average PM-10 concentrations at the Arlington monitor are consistently lower

than the Buckeye monitor within an arc between 230° and 290°. This indicates that

fugitive dust emissions east of Arlington are impacting the Buckeye monitor.

V - 29
Figure V-6

Comparison of WD, WSPD and PM-10 Observations at Arlington, Buckeye and

West 43rd Monitoring Sites During 4/28/2010 - 4/29/2010 High Winds Events

V - 30
Figure V-7

Comparison of WD, WSPD and PM-10 Observations at Arlington, Buckeye and

West 43rd Monitoring Sites During 5/22/2010 - 5/23/2010 High Winds Events

V - 31
If a monitor is overwhelmed by emissions from nearby sources during high wind events,

the variability of PM-10 over the shortest averaging periods (the five-minute data) should

be greater (due to the equivalent variability of soil emissions forced by ground-level

turbulence) than the corresponding variability computed at a station that is impacted by

more distant sources (whose emissions disperse axially along the plume centerline, in

addition to vertically and horizontally, thus reducing significant variations). Data for PM-10

at each five-degree angular direction (Table V-11) show that when the wind comes from

Arlington to Buckeye (230° to 290°), the standard deviations for the Arlington monitor are

usually, but not always, lower than the Buckeye monitor values.

Table V-11

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected at

Arlington and Buckeye Monitors When Winds Are Greater Than 12 mph

WD

Sector

(Degree)

Measurement

Count

Arlington

(μg/m3

)

Buckeye

(μg/m3)

Difference 

(μg/m3)

Standard

Deviation

(Arlington)

Standard

Deviation

(Buckeye)

0 2 233.7 314.1 80.4 31.3 427.6

10 1 18 19.9 1.9 N/A N/A

20 2 41.6 30.4 -11.3 35.2 12

25 5 25.4 27.1 1.8 12.8 9.2

30 23 21.3 24 2.7 20.2 9

35 24 17.1 39.4 22.3 9.1 19.5

40 29 17.3 29.6 12.3 9.6 7.7

45 21 19.1 26.9 7.8 8.7 7.5

50 11 21.3 29.9 8.7 10.6 4

55 3 28.8 40.3 11.6 22.4 18.6

75 2 33.4 36.5 3.1 17.5 15.5

80 3 32.3 33.5 1.3 17.8 19.5

85 1 36.6 20.8 -15.8 N/A N/A

90 1 19.9 29.5 9.6 N/A N/A

140 1 88.1 107 18.9 N/A N/A

155 1 122.8 563.2 440.4 N/A N/A

185 7 40.4 27.7 -12.7 19 13.1

190 4 45.7 50.1 4.4 12.4 31.9

195 6 65.3 60.9 -4.5 74.2 61.9

200 16 55.4 118.6 63.2 67.5 178.5

205 24 55.4 85.4 30 79 136.7

210 26 33.6 80.4 46.8 28.6 190.7

215 36 42.8 60.8 17.9 71.1 54.8

220 36 68.8 84.4 15.7 119.5 67.5

225 32 49.2 44.3 -4.8 80.8 47.9

230 30 34.7 64.2 29.5 36.7 59.3

235 66 44.9 74 29.2 43.7 46.3

240 119 37.5 79.6 42.2 43.8 50.3

245 136 46.4 84.7 38.3 81.9 64.2

V - 32
WD

Sector

(Degree)

Measurement

Count

Arlington

(μg/m3

)

Buckeye

(μg/m3)

Difference 

(μg/m3)

Standard

Deviation

(Arlington)

Standard

Deviation

(Buckeye)

250 122 38.9 71.5 32.5 38.4 55.5

255 110 28.7 51 22.3 25.5 38.1

260 48 35.2 85.5 50.3 48.3 196.4

265 66 36.7 83.6 46.9 52.6 196.7

270 58 37.5 62.2 24.7 46 96.4

275 43 127.9 141.2 13.4 375.5 224.9

280 54 78.2 136.9 58.8 146.4 288.1

285 55 94.2 169 74.8 155.8 243.4

290 45 107.2 157.3 50.1 199.8 195.8

295 19 110.7 105.8 -4.9 174.5 151.2

300 8 298 191.2 -106.8 406.6 293.6

305 4 414.4 234.6 -179.8 321.5 193.4

310 5 217 240.8 23.8 286.5 319.5

315 14 347.7 270.6 -77.1 523.8 406.2

320 18 369.7 188.6 -181.1 653.1 288.7

325 27 473.6 184.1 -289.5 974.7 225

330 27 78.1 50.3 -27.8 180.2 95.8

335 16 26.8 35 8.1 21.5 30.5

340 20 24.6 54.6 30 30.6 131.1

345 11 30.4 36.5 6 21.7 36.8

350 1 16.6 25.1 8.5 N/A N/A

355 4 149.4 67.9 -81.6 132.9 101.8

Calculation of High Wind Background Concentrations

As shown by the measurement count data in Table V-11, the most common direction of

high winds was from the west and southwest (from 200° to 300°). Much lower PM-10

concentrations were observed at both sites when the wind came from the southwest (200°

to 270°), whereas the opposite is true when the wind came from the northwest (270° to

300°). For Arlington, the Palo Verde Nuclear Generating Station, located to the northwest

(270° to 325°), appears to be the source of elevated concentrations. Similarly, the

Mesquite Power Plant located to the southwest (245° to 250°) appears to be the cause of

the higher PM-10 standard deviation at the Arlington monitor relative to Buckeye. 

Another consideration is that the distance from the Arlington site to the Buckeye site is

roughly 11 miles. Any comparison between the two sites should be offset to account for

the time it takes for the wind to travel between the two sites. The values presented in

Table V-11 did not address this offset. Still another consideration is the magnitude of the

concentrations recorded at the two sites. Given the differences in sources surrounding

the two sites, the concentrations located at Arlington should always be lower than those

recorded at Buckeye for individual matched/offset five-minute pairs since the wind should

be picking up anthropogenic emission located between the two sites. 

V - 33
In light of these considerations, the following steps and criteria were used to select the

data used to quantify high wind background concentrations: 

! Wind speed greater than 12 mph at both the Arlington and Buckeye

monitors;

! Consistent with the methodology employed in the temporary monitoring

analysis, measurements at Arlington were lagged 45 minutes to account for

the time it takes for air mass to travel the 11 miles to Buckeye along the 260

degree angle between the two sites (it takes 45 minutes to travel that

distance with a wind speed of 15.2 mph, the value computed for winds in

excess of 12 mph along that angle);

! 230° < WD < 245°, and 250°<WD<270° (Figure V-9) at the Arlington monitor

and at the one-hour-lagged Buckeye monitor; and

! Exclusions of data points where the concentration at Arlington was greater

than that at the Buckeye monitor.

These criteria selected a total of 400 pairs of offset (i.e., lagged) five-minute data at the

Arlington and Buckeye monitoring sites. The average concentration computed from the

selected Arlington data was 27.8 μg/m3; the median concentration was 21.9 μg/m3. The

difference between these values indicates that the distribution of concentrations (and

related wind speeds) is not uniform above 12 mph. Since a higher proportion of the data

is based on lower wind speeds which produce lower concentrations, the median value is

considered to be a more representative measure of non-anthropogenic high wind

background PM-10 concentrations impacting the MAG nonattainment area. A summary

of the selected five-minute pairs at the two sites is presented in Table V-12. When

contrasted with the values in Table V-11, it shows that the above criteria reduced both the

counts of available data and the concentrations recorded at the Arlington site. Figure V-8

presents a plot of the angular segments included and excluded from the datasets included

in Table V-12.

V - 34
Table V-12

Data Used to Calculate High Wind PM-10 Background Concentrations

WD Sector

(Degree)

Measurement 

Count

Arlington

(μg/m3

)

Buckeye

(μg/m3)

Difference 

(μg/m3)

Standard

Deviation

(Arlington)

Standard

Deviation

(Buckeye)

230 22 27.1 73.5 46.4 20.5 62.4

235 46 27.4 66.6 39.2 18.8 38.2

240 97 31.1 79.6 48.4 28.2 48.5

245 0 N/A N/A N/A N/A N/A

250 88 31.1 72.7 41.5 31.6 59.2

255 80 25.7 61.5 35.8 21.9 42.8

260 29 19.5 47.4 27.9 22.3 38.5

265 33 23.7 51.2 27.5 20.3 55.8

270 5 17.9 32.9 15.0 15.3 20.1

Total/Average 400 27.8 67.4 39.6 25.5 50.4

Median N/A 21.9 55.6 33.7 N/A N/A

V - 35
Figure V-8 

Close-In View of Arlington Temporary Monitor and Angular Segments Included

and Excluded from the Background Calculations 

V - 36
Calculation of Low Wind Background Concentrations

The Arlington monitoring data can also be used to quantify non-anthropogenic

concentrations coming in from the desert during low wind conditions. Table V-13 lists the

five-degree angular values for measurement count, average PM-10, and related standard

deviations for low wind conditions (wind speed <=12mph) at the Arlington and Buckeye

monitoring sites. It shows that Arlington concentrations are consistently lower than

Buckeye at any given five degree segment. The lowest Arlington values occur when wind

is coming from the west and southwest (from 200° to 325°). As noted earlier, the upwind

sources from this wind direction are mostly non-anthropogenic, except for the Palo Verde

Nuclear Generating Station and the Mesquite Power Plant. Impacts from these facilities

are much less evident in the data as there is no significant concentration increase; the

same is true for standard deviations, with a few notable exceptions (e.g., 290o). It is also

more difficult to relate the data at Arlington to Buckeye because the wind direction shifts

more frequently, and it takes longer for air parcels to travel from Arlington to Buckeye at

lower wind speeds. For this reason it was determined that the selection of Arlington

values should not be conditioned on Buckeye measurements.

! Given these considerations, the following steps and criteria were used to

select the data used to quantify low wind background concentrations: 

! Wind speed less than or equal to 12 mph at Arlington monitor; and

230° < WD < 245°, and 250°<WD<270° (Figure V-8) at the Arlington monitor

(to be consistent with high wind background calculation).

These criteria selected a total of 17,381 values at Arlington. The average concentration

computed from the data was 18.2 μg/m3

; the median concentration was 14.9 μg/m3. The

difference between these values indicates that the distribution of concentrations is not

uniform at wind speeds below 12 mph. Similar to the high wind analysis, the median value

is considered to be a more representative measure of non-anthropogenic low wind

background PM-10 concentrations impacting the MAG nonattainment area. A summary

of the selected five-minute values is presented in Table V-14.

V - 37
Table V-13

Angular Comparison of Matched Five-Minute PM-10 Concentrations Collected 

at Arlington and Buckeye Monitors When Winds Are Less Than 12 mph

WD

Sector

(Degree)

Measurement

Count

Arlington

(μg/m3

)

Buckeye

(μg/m3)

Difference 

(μg/m3)

Standard

Deviation

(Arlington)

Standard

Deviation

(Buckeye)

0 871 24.6 49.3 24.7 39.0 78.2

5 929 23.5 48.2 24.8 27.9 102.5

10 956 25.1 44.4 19.4 21.7 48.7

15 941 27.3 44.8 17.5 59.7 67.1

20 961 26.0 45.4 19.3 37.0 46.5

25 861 23.2 40.6 17.4 18.9 44.1

30 950 25.3 37.7 12.3 84.2 37.6

35 1035 25.5 40.7 15.2 29.9 60.2

40 1154 26.1 39.0 12.9 50.2 54.2

45 1366 27.6 40.5 12.9 113.2 57.0

50 1592 30.8 37.7 6.9 220.0 51.1

55 1924 33.1 36.3 3.2 152.4 44.7

60 2333 32.8 36.6 3.8 89.4 38.1

65 2423 32.1 36.7 4.6 118.1 36.9

70 2716 31.7 38.0 6.3 76.8 45.2

75 3066 31.5 40.4 9.0 67.5 36.4

80 3027 32.6 40.1 7.5 102.7 32.6

85 2433 30.5 42.2 11.8 26.5 39.0

90 1929 29.5 41.1 11.6 27.2 39.6

95 1682 29.5 42.1 12.6 26.0 45.3

100 1400 28.9 39.4 10.5 29.0 34.9

105 1158 32.9 40.0 7.1 125.3 30.8

110 950 26.7 40.5 13.8 22.1 34.2

115 739 24.5 40.8 16.3 20.4 42.4

120 587 25.4 39.8 14.3 20.8 32.2

125 553 25.7 42.5 16.8 19.7 38.7

130 475 28.0 42.9 14.9 83.9 81.5

135 480 22.6 37.2 14.6 17.5 35.9

140 475 22.3 36.3 14.1 19.5 34.4

145 480 23.2 38.5 15.3 20.8 36.6

150 473 21.5 41.9 20.4 15.9 81.1

155 520 22.0 42.2 20.1 19.4 52.8

160 475 21.8 39.1 17.3 29.2 62.3

165 458 20.5 36.2 15.7 16.8 36.1

170 466 21.3 36.0 14.7 15.0 32.0

175 470 20.8 33.5 12.7 19.7 34.8

180 465 21.1 34.6 13.5 15.9 32.3

185 508 32.3 33.8 1.5 222.4 31.8

190 507 20.2 32.8 12.7 14.9 37.3

V - 38
WD

Sector

(Degree)

Measurement

Count

Arlington

(μg/m3

)

Buckeye

(μg/m3)

Difference 

(μg/m3)

Standard

Deviation

(Arlington)

Standard

Deviation

(Buckeye)

195 630 20.8 31.3 10.5 17.9 36.8

200 687 20.9 34.3 13.4 16.4 54.3

205 774 19.5 33.1 13.6 13.5 44.4

210 832 20.0 31.6 11.6 17.4 33.0

215 994 19.4 30.7 11.3 16.9 32.5

220 1249 18.1 29.0 10.9 14.2 28.3

225 1331 19.2 30.2 11.0 18.3 28.4

230 1539 18.8 33.9 15.0 22.6 32.3

235 2073 17.4 35.2 17.8 12.2 32.2

240 2434 19.1 36.7 17.7 33.4 37.7

245 2347 17.7 36.4 18.6 16.7 37.6

250 2547 18.3 37.6 19.3 24.4 46.4

255 2688 18.0 34.6 16.6 45.7 34.1

260 2489 17.7 32.2 14.4 20.2 33.3

265 1939 18.0 32.2 14.2 20.2 34.6

270 1672 18.3 32.5 14.2 17.5 32.3

275 1723 18.1 34.2 16.1 14.2 36.8

280 1543 18.8 32.3 13.5 17.1 28.7

285 1544 18.4 32.2 13.8 16.1 27.3

290 1405 21.6 35.2 13.6 100.7 61.7

295 1258 18.2 35.9 17.7 14.4 56.8

300 1132 19.6 34.7 15.1 25.9 35.7

305 1134 19.1 35.7 16.6 19.5 35.1

310 1138 19.1 40.1 21.0 15.8 49.7

315 1182 19.0 39.7 20.7 13.5 49.7

320 1291 18.4 37.0 18.5 14.3 41.1

325 1184 20.1 37.6 17.5 17.6 38.6

330 1268 19.9 40.4 20.5 16.2 71.8

335 1228 20.7 39.7 19.0 17.0 52.9

340 1216 20.2 42.9 22.7 14.9 67.3

345 1091 22.2 43.2 21.0 25.6 71.2

350 1037 21.7 43.9 22.3 20.2 51.1

355 868 21.6 42.1 20.5 18.3 48.6

V - 39
Table V-14

Data Used to Calculate Low Wind PM-10 Background Concentrations

WD Sector

(Degree)

Measurement

Count

Arlington

 (μg/m3

)

Standard Deviation

(Arlington)

230 1539 18.8 22.6

235 2073 17.4 12.2

240 2434 19.1 33.4

245 0 N/A N/A

250 2547 18.3 24.4

255 2688 18 45.7

260 2489 17.7 20.2

265 1939 18 20.2

270 1672 18.3 17.5

Total /Average 17381 18.2 27.6

Median N/A 14.9 N/A

V - 40
DESIGN DAY SELECTION

This section describes the process used to select design days for the PM-10 attainment

demonstration in the Maricopa nonattainment area. It identifies three wind speed regimes

that are responsible for PM-10 exceedances in 2007, the year just prior to implementation

of new control measures under the 2007 Five Percent Plan. Since exceedances under

low wind or stagnant conditions have been curtailed by existing controls, the design day

selection is only focused on high wind days. The analysis first eliminates exceedance

days that do not qualify for consideration, then weights the remaining days according to

24-hour average PM-10 concentration, exceedance location, and the number of stations

exceeding on each day. The end result is that June 6, 2007, is recommended as the

design day for the Maricopa PM-10 nonattainment area, and May 4, 2007, is

recommended as the design day for the Salt River modeling domain. 

Introduction

An attainment demonstration requires a baseline, or design day, starting point. Selecting

one or more design days for a PM-10 attainment demonstration in the Maricopa area is

a non-trivial exercise, given the existence of high wind days— when some of the highest

PM-10 concentrations are recorded—that may qualify for exceptional event status under

EPA guidelines. This analysis examines all exceedances that were recorded in the

Maricopa area in 2007 and evaluates which of these are best qualified for a high wind

design day selection.

Exceedance Days

The selection of PM-10 design days was limited to exceedance days recorded in 2007. 

This year was selected because it was the last full year prior to the implementation of

control measures under the MAG 2007 Five Percent Plan, which was adopted in

December 2007. During 2007, exceedances of the 24-hour federal PM-10 ambient air

quality standard were recorded at six monitoring sites in the Maricopa PM-10

nonattainment area. These sites included Coyote Lakes, Central Phoenix, Durango,

Higley, South Phoenix, and West 43rd Avenue. The Buckeye station also exceeded the

standard on two days in 2007, but this monitor is outside the nonattainment area and

therefore was not modeled in this plan. A listing of exceedance days by monitoring site,

together with 24-hour average concentrations and the general meteorological conditions,

is presented in Table V-15.

V - 41
Table V-15

24-Hour Average NAAQS Exceedance Dates, Measured Concentrations and

Associated Meteorological Conditions in 2007

Monitor Date

PM-10 Conc.

(μg/m3) Meteorological Conditions

Buckeye July 19 195.0 Low Winds

November 15 166.2 Irregular Winds

Coyote Lakes July 19 273.4 Thunderstorm Outflow

October 21 312.9 Frontal System High Winds

Central Phoenix July 19 267.8 Thunderstorm Outflow

Durango Complex November 15 155.7 Irregular Winds

Higley June 6 181.0 Frontal System High Winds

July 19 199.5 Thunderstorm Outflow

August 16 195.6 Thunderstorm Outflow

August 23 230.4 Thunderstorm Outflow

October 24 174.8 Frontal System High Winds

South Phoenix April 12 171.1 Frontal System High Winds

August 13 159.5 Thunderstorm Outflow

West 43rd Avenue March 27 227.9 Frontal System High Winds

April 12 202.7 Frontal System High Winds

May 4 197.3 Frontal System High Winds

June 6 225.7 Frontal System High Winds

July 19 178.0 Thunderstorm Outflow

August 16 215.1 Thunderstorm Outflow

Note: The selected design days are highlighted in bold italics and gray shading. The Buckeye monitor is

located outside the PM-10 nonattainment area and is not part of this design day analysis. The Coyote Lakes

monitor was a special purpose monitor that no longer operates and has since been replaced by the Zuni Hills

monitor in late 2009. As such, the Coyote Lakes monitor is not a good candidate for the development of a

design day.

Wind Regimes

All of the exceedances but one occurred on high wind days. The single exception was

July 19, 2007, at the Buckeye station. A high wind day is defined as any day in which fiveminute average wind speeds exceed 12 mph. This cut-point is based upon the work done

in developing the windblown dust emissions inventory in the 2008 Periodic Emissions

Inventory (Appenidx A, Exhibit 1) which shows that generation of windblown dust

emissions on average (throughout the nonattainment area) occurs when five-minute wind

speeds exceed 12 mph. Since not all of the monitoring stations have access to five minute

data, days in which the hourly average wind speed is above 12 mph are thus qualified as

high wind days, as a conservative metric. High wind conditions generally occur in the

Maricopa area under one of two different meteorological regimes: frontal system passage

and thunderstorm outflow. Frontal systems passing over the Maricopa area produce high

winds because of the pressure differences across the front. Air masses move from areas

of high pressure to areas of low pressure, generating winds whose strengths are

V - 42
dependent on the differences in pressure. Because the leading edges of frontal systems

extend for hundreds of miles, the movements of frontal systems produce high winds over

large areas. In the Maricopa area, this phenomenon is characterized by rapid increases

in wind speeds almost simultaneously at many monitoring stations, followed by elevated

wind speeds for several hours afterward as fronts move slowly over the urban area. 

Depending on the strength of the winds associated with a frontal passage, such an event

may overcome the capability of BACM to protect soil surfaces from dust entrainment. 

When this happens, the event may qualify as an exceptional event under EPA guidance.

Thunderstorm outflows, or monsoon winds, produce high velocity winds that are shorter

lived and less geographically expansive than those produced by the passage of frontal

systems. Thunderstorm outflows result from the strong downflows that occur when a

thunderhead collapses. The downflows have sufficient velocity to cause sand saltation

and dust entrainment in areas at the bases of thunderstorms and along the paths of travel

as the downflows expend energy. Both undisturbed desert soils and disturbed soils

controlled by BACM generate significant quantities of PM-10 emissions during these

events. As a result, high PM-10 concentrations resulting from thunderstorm outflows may

qualify for exceptional event status under EPA guidelines.

The July 19, 2007 exceedance at the Buckeye monitor occurred during a period of

relatively low wind conditions at this site. The low hourly average wind speeds and peak

gust velocities that occurred in the early morning hours of this day at Buckeye suggest that

mechanical disturbance—such as by nighttime plowing of fields—was responsible for

elevated PM-10 concentrations from midnight to 7:00 am, when the highest concentrations

of the day were recorded. Meteorological conditions on days such as July 19, 2007, do

not qualify as exceptional events but rather are candidates for design days at stations

within the nonattainment area. Because the Buckeye station is outside the nonattainment

area, July 19, 2007, is not a design day candidate.

The November 15, 2007 exceedance at the Buckeye and Durango monitors occurred

under a mix of low and high wind speeds. Concentrations were elevated throughout the

nonattainment area on this day, suggesting a mix of regional and local sources contributed

to the exceedances. The exceedance at Buckeye is not a candidate for a design day as

it is outside the nonattainment area. The exceedance at Durango barely exceeded the

standard (155.7 μg/m3

), making it a poor candidate for a design day as even the slightest

control measure would result in attainment of the standard. Given the rare mix of both low

and high wind elevated concentrations, a day like this is unlikely to recur, and indeed has

not been replicated since.

Monsoon Days

The days on which monsoon, or thunderstorm outflow, winds occurred are possible

candidates for exceptional event status and not good candidates for design day status. 

These days are distinguished from frontal events that usually occur in spring or fall as a

transport of dust from source regions outside the nonattainment area is clearly associated

V - 43
with monsoon events. On these days, exceptionally high gust velocities occurred for brief

durations— typically only an hour or two—that entrained dust from all types of exposed

soils, including undisturbed desert soils. Additionally, the source area of the thunderstorm

outflows on these days originated in the natural desert areas outside of the PM-10

nonattainment area, transporting large to massive amounts of dust into the PM-10

nonattainment area. The days on which these conditions occurred were July 19 and

August 13, 16, and 23, 2007. On July 19 and August 16, 2007, peak gust velocities

exceeded 40 mph for one or two hours and caused hourly PM-10 concentrations to rise

to levels in the range of 1,700 to 4,000 μg/m3

 at the stations with meteorological towers

that recorded exceedances (Central Phoenix, Higley, and West 43rd Avenue). Although

these sharp rises in concentration occurred only for an hour or two, the magnitudes were

sufficient to cause the 24-hour average on that day to exceed the standard. These days,

at these stations, would not have been exceedances but for the contributions generated

by thunderstorm outflow winds.

Peak gust velocities were lower on August 23, 2007, at the Higley monitor, but hourly PM10 concentrations still rose and fell with the arrival of the dust front associated with a

thunderstorm outflow that had begun to lose strength once encountering the urban edge

of the nonattainment area.. The peak gust velocity ranged between 17 and 28 mph from

8:00 pm to 11:00 pm, as hourly PM-10 concentrations hovered between 900 and 1,800

μg/m3

. The pattern of average wind speed, peak gust velocity, and PM-10 concentration

during these three hours strongly suggests the contribution of transported particulate to

the monitor from outside the immediate area. These trends are displayed in Table V-16.

Table V-16

Hourly PM-10 Concentrations and Wind Speeds at the Higley Monitor 

at 8:00 – 11:00 PM on August 23, 2007

Hour

Hourly PM-10

μg/m3

Avg. Hourly Wind

Speed, mph Peak Gust Speed, mph

7:00 PM 73.7 4.8 27.2

8:00 PM 1865.1 9.2 28.7

9:00 PM 916.9 2.2 9.9

10:00 PM 1065.8 4.3 17.1

11:00 PM 595.2 6.1 13.8

In the hour between 7:00 and 8:00 pm, wind gust speeds rose dramatically near the end

of the hour, causing the peak to reach 27.2 mph while the hourly average wind speed

remained relatively low at 4.8 mph. In the following hour, gust velocities remained

elevated while the average wind speed climbed to 9.2 mph and the hourly PM-10

concentration climbed to 1,865 μg/m3

. Then, in the next hour, both gust speeds and the

average hourly wind speed dropped dramatically while the hourly PM-10 concentration

remained at a relatively high 920 μg/m3

. Between 10:00 and 11:00 pm, wind speeds rose

again, doubling in magnitude, but the hourly PM-10 concentration rose by only 16%. In

V - 44
the subsequent hour, the PM-10 concentration drops by 44% while the average hourly

wind speed increases by 42%. This pattern is typical of thunderstorm outflows that

dissipate in strength when reaching the increased surface roughness of the urban

boundaries of the nonattainment area where the wind speeds and gust are typically low

to moderate, but the associated transported dust remains in the air and can take several

hours to deposit out of the atmosphere.

A similar, but shorter, episode occurred on August 13, 2007, at the South Phoenix monitor. 

On this day, the peak gust velocity rose to 24.9 mph between 11:00 pm and midnight,

while the hourly PM-10 concentration rose to 2,600 μg/m3. During the remainder of the

day, PM-10 concentrations and wind speeds were typical of a light wind day. The

contribution of this last hour of the day caused the 24-hour average PM-10 concentration

to rise to 159.5 μg/m3

, resulting in an exceedance. The hourly PM-10 concentrations and

wind speeds for this day are shown in Table V-17.

During the last hour of this day, the peak gust velocity exceeded the second highest value

of the day by 40%, but the hourly average wind speed was greater than the second

highest value in this column by only 4%. At the same time, the hourly PM-10

concentration was 2,639% higher than the second highest value of the day. Similar to the

August 23rd event, the implication of these data is that the thunderstorm outflow that

reached the South Phoenix monitor just before midnight transported significant PM-10

from upwind sources south of the monitor, which includes a limited fetch of urban area and

a significant swath of undisturbed desert soils, even as the thunderstorm outflow itself had

lost energy on arrival at the South Phoenix monitor.

The significant contribution of transported PM-10 on August 13 and 23, 2007, leads to the

same result: further control of sources near this monitor will not eliminate this type of

exceedance, and these episodes should be designated exceptional events under EPA

guidance.

V - 45
Table V-17

Hourly PM-10 Concentrations and Wind Speeds

at the South Phoenix Monitor on August 13, 2007

Hour

Hourly PM-10,

μg/m3

Avg. Hourly Wind

Speed, mph Peak Gust Speed, mph

0:00 AM 31.2 0.4 3.3

1:00 AM 32.9 1.2 4.4

2:00 AM 23.9 1.0 4.1

3:00 AM 30.9 0.4 1.9

4:00 AM 35.9 1.6 4.5

5:00 AM 46.9 1.3 3.5

6:00 AM 75.9 2.4 7.7

7:00 AM 64.8 6.1 12.2

8:00 AM 53.4 5.0 10.5

9:00 AM 47.9 5.1 12.3

10:00 AM 40.9 2.4 11.2

11:00 AM 42.1 3.0 12.2

12:00 PM 52.1 7.0 15.1

1:00 PM 98.5 6.5 16.4

2:00 PM 97.2 5.2 15.5

3:00 PM 87.5 5.0 15.2

4:00 PM 69.0 7.1 16.4

5:00 PM 51.3 6.6 15.4

6:00 PM 43.1 6.7 13.5

7:00 PM 51.4 4.9 12.0

8:00 PM 38.9 3.2 9.8

9:00 PM 41.6 4.4 10.8

10:00 PM 71.9 5.8 17.8

11:00 PM 2599.2 7.4 24.9

Frontal Wind Days

On frontal wind days, peak hourly PM-10 concentrations are lower than those occurring

on monsoon days, high winds occur for longer durations, and peak gust speeds range a

little lower than those recorded on monsoon days. Frontal wind days produced

significantly more hours during 2007 in which PM-10 concentrations exceeded the level

of the 24-hour standard than are produced on monsoon days. Table V-18 compares some

of the totals in 2007 for PM-10 exceedance days and high wind hours as grouped by wind

regime. A listing of the frontal wind days on which the 24-hour standard was exceeded

in 2007 within the Maricopa nonattainment area is presented in Table V-19.

V - 46
Table V-18

Comparison of PM-10 Concentrations During 2007 Exceedance Days

Under Different Wind Regimes

Wind

Regime

Average of

Highest PM-10

Concentrations, μg/m3

Annual Hours

that Exceed

the Standard

Percentage of Annual

Hours that Exceed

the Standard

Frontal 831.5 69 60.5%

Monsoon 2445.1 28 24.6%

Other1 355.5 17 14.9% 1

 Includes data from days with low and irregular winds.

Table V-19

Peak Hourly PM-10 Concentrations and Wind Speeds

In the Maricopa Nonattainment Area During 2007

Site Date

Hours

Exceeding

Standard

Highest

PM

Max

Wind

Gust

High

Wind

Hours

Higley 6/6/2007 9 580.2 37.7 8

West 43rd 3/27/2007 11 794.4 44.6 11

West 43rd 4/12/2007 9 774.9 45.5 7

West 43rd 5/4/2007 11 570 35.2 10

West 43rd 6/6/2007 12 662.3 33.4 12

Coyote Lakes 10/21/2007 10 1569.2 NA 15

Higley 10/24/2007 7 869.8 33.2 4

Days on which the peak gust velocity were the highest may be flagged as exceptional

events due to the capability of such winds to overcome BACM controls and the possible

presence of transported PM-10 from sources both within and outside the nonattainment

area. While the previous sections in this chapter describing the temporary monitoring

insights and source weighting point to the importance of near-by sources during high wind

events, long range transport can also occur on these days when wind speeds are

unusually high. Evidence of such transport can be seen on days such as April 12, 2007,

when the State Super Site monitor recorded hourly PM-10 concentrations as high as 337.9

μg/m3

 in the presence of minimal significant localized fugitive dust sources around the

monitor. Such a designation as an exceptional event eliminates March 27 (one monitor

exceeded) and April 12, 2007 (two monitors exceeded), because the exceedances on

these days are associated with peak gust velocities that can easily generate PM-10 from

controlled and natural surfaces. Several other monitors in nearby Arizona counties and

eastern Californian desert counties also recorded exceedances on these days, suggesting

the presence of regionally transported PM-10 along with the elevated wind speeds.

V - 47
The exceedance recorded at Coyote Lakes on October 21, 2007, is also not considered

in this analysis as this temporary installation was a special-purpose monitor that no longer

operates and has since been replaced by the nearby (approximately 1.75 miles) Zuni Hills

monitor in late 2009. No exceedances of the PM-10 standard were recorded at the Zuni

Hills monitor in 2009 or 2010. As such, the Coyote lakes monitor is a poor candidate for

the development of a design day.

Of the remaining days, June 6, 2007, is the only day on which more than one monitor

exceeded the standard during the passage of a storm front. On this day, hourly average

wind speeds began at moderate levels and rose during daylight hours to peak in the early

afternoon. Wind speeds then dropped to the lowest levels of the day by midnight. Hourly

PM-10 concentrations followed a similar trend with sharper increases when hourly wind

speeds exceeded about 12 mph, with faster declines due to exhaustion of particulate

entrainment from limited reservoir soils even as wind speeds remained steady for a few

hours. Plots of hourly average wind speed and PM-10 concentrations for the West 43rd

Avenue and Higley sites are presented in Figures V-9 and V-10, respectively.

The relationships between wind speeds and PM-10 concentrations at these two sites on

June 6, 2007, suggest that local sources were primarily responsible for PM-10 impacting

the monitors. As Figure V-9 indicates, elevated wind speeds above 12 mph (the speed

at which wind entrainment of dust commences in the Maricopa area) were present at West

43rd Avenue for 12 hours, generating 73% of the 24-hour PM-10 concentration of 225.7

μg/m3

. The 24-hour concentration value at West 43rd Avenue is also the maximum

concentration seen for an exceedance day that is not a clear candidate for an exceptional

event. Elevated wind speeds above 12 mph were present for 8 hours on June 6 at the

Higley site, accounting for 66% of the average 24-hour PM-10 concentration of 181.0

μg/m3

. In comparison to the Higley monitor, this day is also similar to the exceedance

seen at the Higley monitor under frontal winds on October 24, 2007, implying that the

controls that would bring attainment to Higley on June 6, 2007, would also provide

attainment at Higley on October 24, 2007. On this basis, June 6, 2007, is the best design

day for an attainment demonstration throughout the nonattainment area.

V - 48
Figure V-9

Hourly Average Wind Speed and PM-10 Concentration at West 43rd Avenue

Monitor on June 6, 2007

V - 49
Figure V-10

Hourly Average Wind Speed and PM-10 Concentration

 at Higley Monitor on June 6, 2007

V - 50
Of the eight exceedance days that occurred in the Salt River area modeling domain

(encompassing the Durango Complex, South Phoenix, and West 43rd Avenue monitors),

only one exceedance day remains that has not been previously ruled out (November 15,

2007, at Durango) or modeled (June 6, 2007), or may be an exceptional event: May 4,

2007. A concentration of 197.3 μg/m3 was measured at the West 43rd Avenue site on this

day, which experienced 10 hours with average hourly wind speeds in excess of 12 mph. 

These high wind hours contributed 74% of the 24-hour average PM-10 concentration. The

pattern of hourly wind speeds and PM-10 concentrations on this date suggests that local

sources contributed the predominant fraction of PM-10 recorded at the West 43rd Avenue

monitor, making this day the design day choice for the Salt River area modeling. A plot

of hourly average wind speeds and PM-10 concentrations is included in Figure V-11.

Figure V-11

Hourly Average Wind Speed and PM-10 Concentration

at West 43rd Avenue Monitoring Station on May 4, 2007

V - 51
Conclusions

In 2007, the 24-hour PM-10 standard was exceeded 19 times, on 11 unique days at the

monitoring stations in the Maricopa County. Two of these exceedances were recorded at

the Buckeye station, which is outside the PM-10 nonattainment area, and two were

recorded at the Coyote Lakes site, which was a temporary special studies site no longer

in operation. The Coyote Lakes monitor has since been replaced with the nearby Zuni

Hills monitor in late 2009 which has not recorded an exceedance in 2009 or 2010. As

such the Coyote Lakes monitor is a poor choice for development of a design day and

these exceedances, along with those at the Buckeye monitor, have been excluded as

candidates for design days within the nonattainment area. Of the remaining 15

exceedances, seven occurred on monsoon (thunderstorm outflow) days, which likely

qualifies these exceedances for exceptional event status but not for consideration as

design days. An additional three exceedances occurred during very strong synoptic frontal

winds, which may also qualifies these exceedances for exceptional event status. Of the

remaining five exceedances, two occurred on June 6, 2007, which is recommended to be

the design day for the Maricopa nonattainment area. Of the further remaining three

exceedances, one occurred at the Higley monitor (October 24, 2007) and is similar in

nature to the modeled June 6, 2007 design day. The other two exceedances (May 4,

2007, and November 15, 2007) occurred within the Salt River modeling domain. 

November 15, 2007 was excluded as an outlier event and because its 24-hour value was

barely over the standard (155.7 μg/m3

), leaving the exceedance of May 4, 2007 at the

West 43rd Avenue monitor as the final choice to of a design day for the Salt River area

domain.

V - 52
MODELING DOMAINS

As explained earlier in the conceptual model section, separate modeling domains were

developed for the high and low wind hours on each of the design days. Hourly high wind

domains were developed using back trajectories calculated with wind speed and direction

data from the modeled monitor. Domains for the low wind hours are represented by the

sources and land uses surrounding each of the monitors. The basis for distinguishing

between high and low wind hours is the 12 mph windblown dust threshold developed in

the 2008 PM-10 Periodic Emissions Inventory (Appendix A, Exhibit 1). This section

discusses in detail the development of the low and high wind domains. Table V-20 shows

the breakout between high and low wind hours for each of the design day-modeled

monitors.

V - 53
Table V-20

Breakout of High and Low Wind Hours on Modeled Design Days at Each Monitor

Hour

5/4/2007 6/6/2007

West 43rd West 43rd

Central

Phoenix Durango Greenwood Higley

State

SuperSite

West

Phoenix

(Hourly Average Wind Speed in mph)

0 2.5 13.3 12.5 8.9 8.1 7.4 7.6 7.1

1 1.4 9.9 13.1 6.3 5.7 5.8 6.3 7.8

2 0.4 9.1 8.6 5.0 4.9 8.8 5.4 8.4

3 5.5 7.8 8.0 1.0 2.9 9.0 5.4 4.2

4 6.7 10.6 10.9 2.6 2.1 9.1 6.7 5.1

5 8.5 14.5 10.3 7.3 5.4 7.4 7.2 6.1

6 7.2 14.9 12.4 9.1 6.7 9.4 7.2 8.5

7 4.9 11.4 12.8 8.7 7.7 9.4 6.5 10.3

8 4.5 11.3 11.1 10.5 8.3 10.8 7.2 8.7

9 9.2 12.0 11.3 11.2 10.0 11.6 6.7 8.6

10 9.4 13.8 12.1 11.9 11.0 14.6 6.9 8.8

11 10.6 16.0 13.9 12.5 10.8 15.2 9.4 12.1

12 13.4 16.6 15.3 13.9 12.7 17.6 8.9 13.6

13 17.6 15.1 15.4 13.5 12.6 15.3 9.8 15.1

14 17.4 17.6 16.9 15.7 15.4 15.8 10.5 15.1

15 18.7 18.1 17.8 17.9 13.9 15.6 11.4 13.5

16 17.7 17.0 15.7 14.5 11.9 15.3 10.1 12.0

17 19.4 14.5 14.0 12.9 11.7 13.5 9.2 11.7

18 17.6 14.9 14.0 10.3 11.4 10.1 11.2 10.0

19 15.5 12.0 11.9 8.9 8.7 6.9 9.6 9.3

20 9.8 8.8 11.1 6.4 7.4 6.6 7.8 9.1

21 13.6 9.3 11.7 7.5 7.0 7.1 6.3 6.8

22 15.6 7.0 8.8 6.3 5.1 2.9 3.8 5.3

23 11.6 6.8 8.5 5.2 4.0 3.2 3.6 4.8

Note: High wind hours are higlighted in bold italics.

High Wind Domains

High wind back trajectories are developed for any monitor-specific design-day hour with

an average wind speed over 12 mph. When available, five-minute average wind speed

and direction, as measured by the modeled monitor, was used to develop the back

trajectories from which the modeling domains are developed. When five-minute data is

unavailable, hourly wind speed and direction is used. The length of the back trajectory is

V - 54
determined by the magnitude of the wind speed (e.g., an hourly average wind speed of

15 mph will produce a back trajectory 15 miles in length). 

The back trajectory plots are generated based on either hourly or the five-minute surface

wind speed (WS) and wind direction (WD) data. This back trajectory calculation only

considers the horizontal air movement and ignores the vertical movement of the air. The

trajectories are presented as a sequence of UTM coordinates for the endpoints of each

specific time interval being simulated. Using five-minute data as an example, The X and

Y of the UTM coordinates for each five minute interval are calculated as following:

X=X1+WS*0.447*60*5*SIN(WD*2*PI/360)

Y=Y1+WS*0.447*60*5*COS(WD*2*PI/360)

Where X and Y are the UTM coordinates of the current five minutes interval back

trajectory endpoints; X1 and Y1 are the endpoints for the previous five minutes interval

back trajectory; WS and WD are the wind speed (MPH) and Wind direction (degree)

observation during the current five minutes. 0.447 ms-1/mph is the WS unit conversion

factor from MPH to m/s, 60 seconds/minute * 5 minute is the air traveling time (seconds)

during the five minutes, and 2*PI/360 is the conversion factor from degrees to Radians. 

This process is completed and mapped for each high wind hour back trajectory in ArcGIS. 

Establishing the Boundaries of a High Wind Domain - Once all of the back trajectories

have been mapped, it is necessary to determine how far to extend the domain from either

side of the back trajectory. This issue was explored in modeling efforts that focused on

the West 43rd Avenue monitor in the Salt River area. A summary of those efforts are

presented below and conclude that a one mile buffer on either side of the back trajectory

is a conservative representation of the domain for high wind sources.

The analysis of emissions impacting the West 43rd Avenue monitoring station during high

wind events included inventories of emissions in upwind areas. Defining the specific

domain boundaries of upwind areas within which to focus emission data collection was

both necessitated by the significance of source proximity to the monitor during high wind

hours, and facilitated by the land use database maintained in GIS format by MAG.

Analysis of wind directions and speeds during hours when the West 43rd Avenue station

exceeded 150 μg/m3

found that winds were primarily from the west-southwest along the

Salt River, possibly influenced by orographic affects. Exceedance hours generally began

when average hourly wind speeds exceeded 12 mph. At this speed, sources that may be

located three hours upwind – a period of time during which the coarse fraction of windentrained dust will settle out of the air - would be located beyond the urban and agricultural

boundaries to the west of the West 43rd Avenue station. Thus, the western boundary of

each back-trajectory emission inventory domain was set at the edge of development

(whether for agricultural or other use), typically just east of the Buckeye monitoring station. 

The eastern boundary was invariably set at the location of the West 43rd station.

V - 55
Entrained dust plumes from disturbed lands spread horizontally and vertically as winds

carry suspended particulate downwind. Analysis of in-plume concentrations predicted by

a computer dispersion model (AERMOD) shows that the rate of spread decreases as wind

speed increases. The modeling scenario used to determine the distance-related reduction

factor to use in weighting emissions in a modified rollback analysis, as described in Source

Weighting Analysis section, was also used to estimate the angular arc of a dust plume

perpendicular to its centerline at different wind speeds. 

Receptor sites lateral to the plume centerline were located at the same downwind

distances from the hypothetical area source as those sited along the plume centerline. 

As in the weighting factor analysis, the AERMOD model was run at several different wind

speeds ranging from 12 to 24 mph. The edge of each plume was identified in the output

as the location of the lateral receptor closest downwind to the source that first registered

a non-zero PM-10 concentration. A tabulation of the arcs subtended by plumes at

increasing wind speeds, as reported by the modeling output data, is shown in Table V-21. 

At the minimum high wind speed of 12 mph, the arc subtended by a dust plume is

estimated to be 34.2 degrees, or 17.1 degrees on each side of the downwind centerline.

Table V-21

Dust Plume Arc as a Function of Wind Speed

Hourly Average Wind Speed (mph) Plume Arc (degrees)

12.0 34.2

15.0 33.1

18.0 28.8

21.0 25.9

24.0 22.7

The Estrella Mountains to the south of the Salt River have the potential to channelize high

speed wind flows approaching from the west. This suggests that winds can be converging

upwind of the West 43rd Avenue station in a manner that would not be detected by the

wind instruments operating at the monitoring site. Such convergence would bring

emissions from lands outside the 34.2 degree arc upwind of the station into the wind field

bounded by the arc and impact the monitor. In order to account for this potential, and in

an exercise of conservatism, the angle subtended by the modeled arc was doubled to

assure that all upwind contributing sources were included within the high wind inventory

domain. This assumption increased the upwind arc to a full angle of 68.4 degrees, or 34.2

degrees on each side of the back trajectory centerline.

The emission weighting analysis demonstrated that PM10 concentrations drop

dramatically with increasing distance downwind of an area source under high wind

conditions. For example, under an hourly average wind speed of 12 mph, PM10

concentrations decline by two orders of magnitude, or 99%, between a fence line location

V - 56
at the downwind edge of an area source and a plume centerline location 1.74 miles

downwind. This reduction factor of 99% was considered to be significant and was used

as a basis for the design of the emission inventory domain straddling the back trajectory

centerline.

At a location 1.74 miles upwind of the West 43rd Avenue monitor, the width of a 68.4

degree arc would be 2.36 miles. Within this arc and downwind distance, sources

contributing a significant majority of emissions impacting the monitor will be located – if the

emission density of windblown PM10 is reasonably uniform within the upwind Salt River

belt. A full arc width of 2.36 miles translates into an arc width on each side of the back

trajectory centerline of 1.18 miles. This value was rounded downward to 1.0 miles to

represent the width of the modeling domain on each side of the centerline.

In summary, all of the land uses within the resulting high wind domain that can generate

windblown dust are included as emissions sources for the attainment modeling. Figure

V-12 provides an example of a calculated high wind back trajectory and resulting domain.

V - 57
Figure V-12

Example High Wind Back Trajectory and Resulting High Wind Domain

 (Hour 15 from West 43rd Avenue Monitor on June 6, 2007)

Low Wind Domains

Spatial domains for the low wind hours were developed based upon the predominant land

uses surrounding each modeled monitor. The nonattainment area as a whole is too large

to be representative of the PM-10 emissions around the modeled monitors. As such,

smaller subsets of the nonattainment area are necessary in order to accurately represent

the mix of sources around each modeled monitor. Three separate low wind modeling

domains were developed as part of the attainment demonstration to aid in focusing on the

low wind sources around each monitor. 

Considerable effort has been expended in previous PM-10 air quality plans in developing

the Salt River area domain. This area is modeled both on its own and as part of the

V - 58
regional nonattainment area demonstration. This domain is considered to contain the

worst-case representation of PM-10 sources in the nonattainment area and has the

highest density of PM-10 emissions under low wind conditions. All major sources of PM10 emissions, except unpaved roads, are represented in this area. These sources include

light and heavy dust-generating industries, active agricultural land, active earthmoving

sites, vacant lots and unpaved parking areas. There are three active PM-10 monitors that

lie within the Salt River domain: West 43rd Avenue, South Phoenix and Durango Complex. 

This 36 square mile domain is bounded by Van Buren Street to the north, Baseline Road

to the south, 59th Avenue to the west and 7th Street to the east. Figure V-13 displays the

Salt River area low wind domain.

Figure V-13

Salt River Area Low Wind Domain

A second domain, located around the east valley Higley monitor was developed to

represent the mix of sources in that area. This area is modeled as part of the regional

attainment demonstration on June 6, 2007. Predominant PM-10 sources within the Higley

domain include active agricultural fields, active earthmoving operations and a major

V - 59
regional freeway. This 16 square mile domain is bounded by Warner Road to the north,

Germann Road to the south, Val Vista Drive to the west and Power Road to the east. 

Figure V-14 displays the Higley low wind domain.

Figure V-14

Higley Low Wind Domain

The last low wind domain developed for the attainment demonstration contains four PM-10

monitors (modeled as part of the regional attainment demonstration) located in the center

of the nonattainment area: Central Phoenix, Greenwood, State Super Site and West

Phoenix. These monitors are all located in areas that have similar land uses of dense

residential and light industrial/commercial/retail. In terms of PM-10 sources, the largest

sources are light dust-generating industries, active earthmoving sites and major

transportation corridors. This 40 square mile domain is bounded by Missouri Avenue to

the north, Harrison Street to the south, 51st Avenue to the west and 24th Street to the east. 

Figure V-15 displays the Central City low wind domain.

V - 60
Figure V-15

Central City Low Wind Domain

V - 61
INVENTORY DEVELOPMENT

Under a rollback modeling scheme, reductions of emissions that impact the monitor are

assumed to result in an equal reduction in monitor concentrations. As such, both base

case (2007) low and high wind inventories must be developed along with control case

(2012) low and high wind inventories. This following describes in detail how the 2007 base

year and 2012 control/attainment year high and low wind inventories were developed. 

Details on how the base and attainment year inventories are developed for the entire

nonattainment area are presented in Chapters II and III of this TSD.

High Wind Inventories

For the high wind hours, hourly windblown PM-10 emissions are calculated based upon

the land uses that fall within each of the hourly high wind domains. Land use data, with

the exception of construction data, comes from the MAG information services and

represents land use patterns as of 2009. Land use is held constant between calculation

of 2007 and 2012 year inventories. A detailed write-up of how the land use data is created

is included in the 2008 PM-10 Periodic Emissions Inventory as an Appendix to the

windblown dust section. Construction data was provided by the Maricopa County Air

Quality Department for the year 2007. To be conservative this data is also held constant

through 2012 even though there is substantially less construction occurring due to the

economic recession. Windblown PM-10 emissions for the subject land uses are calculated

per the methodology described in the 2008 PM-10 Periodic Emissions Inventory (Appendix

A, Exhibit 1). As an example, emissions from the West 43rd Avenue monitor hour 15 high

wind domain (June 6, 2007 design day) are explained below. All of the hourly high wind

emissions are calculated in the same manner shown in this example.

Initially, through the use of ArcGIS, the land uses subject to windblown dust emissions

within the high wind domain are identified. For the hour 15 example, 11 unique land uses

within the high wind domain are subject to windblown dust as shown in Figure V-16. They

include the land uses of Active Open Space (i.e., parks), Agriculture, Commercial,

Construction, Coreslab (a large combination of sand and gravel and industrial facility),

Industrial, Passive/Restricted Open Space (i.e., preserves), Public/Military Space (i.e.,

jails, bases), Sand and Gravel facilities, Vacant, and Dry Washes. These land uses are

chosen because either all or some of their acreage is bare soil from which windblown dust

can be generated. Land uses such as residential or golf courses are not included as land

uses subject to windblown dust since none (or a very limited amount) of the acreage

associated with these land uses is bare soil. Land uses on the steep slopes of mountain

preserves are also excluded as the surface roughness of the slope severely limits the

production of windblown dust. 

After the land uses are identified, a 10-acre fishnet grid is applied to the land uses, so that

no individual land use parcel is larger than ten acres. This allows for calculating the

distance from each parcel boundary to the modeled monitor; which is West 43rd Avenue

in this example. The distance of the parcel to the monitor is necessary in order to apply

V - 62
the distance weighting factor to the calculated emissions as discussed earlier in this

chapter.

Figure V-16

Land Uses Capable of Producing Windblown Dust Within the Hour 15, West 43rd

Avenue Monitor, High Wind Domain (June 6, 2007)

To be conservative, all but four of the land uses shown above are assumed to have 100%

of their acreage capable of emitting windblown dust. The land uses of Commercial,

Coreslab, Industrial and Public/Military are exempted from this assumption because these

land uses are known to have a mix of large buildings and paved parking lots/access roads

in addition to areas of bare soil. Over 2500 aerial photographs of these types of parcels

in the Salt River area were evaluated to determine the average percentage of bare soil

present on each of these land uses. The results of that analysis are listed in Table V-22. 

To be conservative, the mean value was chosen to represent the average percentage of

bare soil on these land uses, as this value was higher than the median in all cases. Note

that Coreslab is considered an industrial parcel, and as such is assigned the average of

24% for the amount of bare soil present. 

V - 63
Table V-22

Results of Aerial Photography Analysis of Percentage of Bare Soil on Land Uses

with Both Bare and Covered Surfaces

Land Use Mean Median Std. Deviation

Commercial 26% 20% 23%

Industrial 24% 17% 21%

Public/Military 35% 21% 35%

After the land uses within the high wind domain have been classified and selected, the

process for calculating windblown emissions from these land uses can begin. The 2008

PM-10 Periodic Emissions Inventory developed emission factors for two classes of bare

soil: disturbed and stable. Disturbed soils emit at a much higher rate than stabilized soils

because there is more loose soil available to be entrained by the wind. As wind speeds

increase, both disturbed and stable soils emit at higher rates, as the extra energy from the

wind entrains more material from both surfaces. Thus, the main elements needed to

calculate windblown PM-10 emissions are the number of acres of bare soil, the wind

speeds over that soil, and the percentage of the acres that are disturbed or stable.

Table V-23 displays the emission factors by wind speed bins as developed in the 2008

Periodic Emissions Inventory. These emission factors were developed based upon local

testing of Arizona soils. The units of the emission factors are tons per acre per fiveminute, as the input wind speed data for most of the high wind domains is a five-minute

average wind speed. 

Table V-23

Windblown PM-10 Emission Factors (tons /acre-five-minute)

by 10-Meter Wind Speed Bin and Soil Stabilization

Soil

Stabilization

Wind Speed

12-15 mph

Wind Speed

15-20 mph

Wind Speed

20-25 mph

Wind Speed

25-30 mph

Wind Speed

30-35 mph

Disturbed 5.44E-05 1.69E-04 5.14E-04 1.24E-03 2.57E-03

Stable 1.10E-05 2.93E-05 7.68E-05 1.64E-04 3.10E-04

Continuing with the use of the hour 15, West 43rd Avenue, high wind domain example, the

hourly average wind speed for that hour was 18.1 mph. An examination of the five-minute

wind speed data for that hour reveals that ten of the five minute periods had wind speeds

between 15-20 mph and two of the five minute periods had wind speeds between 20-25

mph. This means that the emissions factors from only two wind speed bins (15-20 and

20-25) will be used to calculate emissions for this hour.

At this point, the amount of acreage by land use and the five minute wind speeds have

been determined for the example high wind domain. The one variable that is left to be

V - 64
determined is how much of the land use acreage is disturbed or stable. A direct

measurement of this variable is not possible, as stabilization rates change over time with

meteorological and anthropogenic activities unique to each individual parcel. Therefore,

a surrogate variable is needed to assume an average disturbance level for each land use

subject to producing windblown dust. As discussed in Chapter Five of the main plan and

the 2008 PM-10 Periodic Emissions Inventory, rule effectiveness has been chosen as the

surrogate for the disturbance levels of bare soils. As an example, a rule effectiveness of

80% would assume that 80% of the acreage is stable and 20% is disturbed. Maricopa

County Air Quality Department performed rule effectiveness studies for three fugitive dust

rules: Rule 310, earthmoving activities, Rule 310.01, open and vacant areas, and Rule

316, sand and gravel sites. These studies were done on an annual basis and are shown

in Table V-24. The values for calendar years 2007, 2008 and 2010 were all derived per

the methodology listed in the 2008 PM-10 Periodic Emissions Inventory. The increases

in rule effectiveness through time is a direct result of the implementation of the control

measures in this plan. The value for 2012 is the assumed value achieved as a result of

the control measures in this plan projected out through 2012 (See Chapter Five of main

plan for more explanation).

Table V-24

Calendar Year Rule Effectiveness Rates as Surrogates

for Soil Disturbance Rates

Rule 2007 2008 2010 2012

310 76% 90% 94% 94%

310.01 85% 95% 96% 97%

316 40% 65% 73% 73%

The 11 land uses identified earlier in Figure V-16 are thus assigned disturbance rates

based upon the rule effectiveness rates in Table V-24. Rule 310 serves as a surrogate

value for construction land uses, Rule 316 serves as a surrogate for sand and gravel land

uses, and Rule 310.01 serves as a surrogate for all remaining land uses. Rule 310.01

directly regulates all open areas and industrial/commercial areas that are permitted or unpermitted. The only land use under which Rule 310.01 does not regulate is agriculture. 

However, because there are no quantitative rule effectiveness or disturbance rates studies

available that are applicable to agricultural land, Rule 310.01 disturbance rates are

assumed to apply, as was assumed in the 2008 PM-10 Periodic Emissions Inventory. It

is important to point out however, that because there are no benefits for agricultural land

taken as part of the attainment demonstration or the five percent reductions, the assumed

2007 rule 310.01 effectiveness rate of 85% is held constant through 2012, meaning

windblown dust emissions from agricultural lands in 2012 are the same as in 2007. All

other land uses besides agriculture experience a reduction in emissions between 2007

and 2012 as a result of the benefit of increased rule effectiveness; which is pragmatically

translating as an assumption of less disturbed soil in the windblown dust inventory.

V - 65
Now that all of the required elements (acreage, percent disturbed, and wind speeds) have

been determined, the elements are simply multiplied in order to obtain PM-10 windblown

dust emissions for each land use within the high wind domain. An example equation using

data from the hour 15 example high wind domain is shown below to detail how high wind

emissions are calculated:

Example for calculating base year (2007) windblown dust emissions from Commercial land

uses:

(1) Land use * % acreage * 15-20 mph wind * % Stable * Stable 15-20 mph = Stable Emissions

Acreage of bare soil speed periods emission factor

(250.2) * (26%) * (10) * (85%) * (2.93E-05) = 1.62E-02 Tons

+

(2) Land use * % acreage * 20-25 mph wind * % Stable * Stable 20-25 mph = Stable Emissions

Acreage of bare soil speed periods emission factor

(250.2) * (26%) * (2) * (85%) * (7.68E-05) = 8.49E-03 Tons

 +

(3) Land use * % acreage * 15-20 mph wind * % Disturbed * Disturbed 15-20 mph = Disturbed

Emissions

Acreage of bare soil speed periods emission factor

(250.2) * (26%) * (10) * (15%) * (1.69E-04) = 1.65E-02 Tons 

+

(4) Land use * % acreage * 20-25 mph wind * % Disturbed * Disturbed 20-25 mph = Disturbed

Emissions

Acreage of bare soil speed periods emission factor

(250.2) * (26%) * (2) * (15%) * (5.14E-04) = 1.00E-02 Tons

Sum of above equations (1 through 4) = 5.12E-02 Tons of PM-10 emissions from Commercial land uses.

This process is repeated for all land uses and then summed to calculate total PM-10

emissions from all land uses within the high wind domain. The only difference between

2007 and 2012 year emissions is that the disturbance rates change based upon gains in

rule effectiveness, thus the reductions in emissions between 2007 and 2012 are solely

attributable to increases in rule effectiveness.

The emissions that are calculated per the steps above, represent maximum potential PM10 emissions from windblown dust. As explained in the 2008 PM-10 Periodic Emissions

Inventory, a whole host of other factors including supply limitations, surface roughness,

soil moisture content, vegetative cover, soil texture, etc. and would likely limit the PM-10

emissions from windblown dust to levels below what is calculated in each of the high wind

domains. The 2008 PM-10 Emissions Inventory corrects for these limiters by

standardizing PM-10 emissions as compared to concentrations seen at the monitor under

high wind conditions. This helps to ensure the scale of the emissions estimate is not too

V - 66
large. However, this step is not necessary for high wind emission inventories prepared for

use in an attainment demonstration, as what is important in this rollback modeling is the

difference between 2007 and 2012 emissions, not the scale of those emissions as

compared to low wind emission sources. Since both 2007 and 2012 high wind emissions

are calculated in the same way, the difference between the two inventories provides the

reductions needed to model attainment at the monitors. The unit and scale of the

inventories thus do not matter, only that the methodology is the same between the base

and controlled inventories in order to claim the benefits of the measures in this plan as

applied to the modeled concentrations.

Once high wind PM-10 emissions have been calculated for the land uses, one final step

is required to prepare the emissions for attainment modeling. The calculated emissions

for each land use parcel are divided by the distance (feet) from the modeled monitor. As

discussed in an earlier section in this chapter, distance weighting is applied to this

emissions in order to account for their diminishing impact on monitor concentrations with

distance. The best weighting function was determined to be a simple inverse distance

ratio (1/d) through analysis of dispersion behavior provided by sample AERMOD model

runs (see earlier sections on source weighting and temporary monitor insights).

Tables V-25 through V-31 provide the results of the high wind emissions inventories for

the high wind domains of each modeled monitor, based upon the process outlined above. 

They list both the calculated emissions and the inverse-distance weighted emissions for

the base and controlled year inventories.

V - 67
Table V-25

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for May 4, 2007 Design Day at the West 43rd Avenue Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

12 3.05 2.09 2.872E-04 1.900E-04 33.8%

13 9.49 6.36 6.529E-04 4.245E-04 35.0%

14 9.94 6.67 6.866E-04 4.454E-04 35.1%

15 13.94 9.19 8.721E-04 5.581E-04 36.0%

16 13.36 8.81 8.921E-04 5.699E-04 36.1%

17 19.01 12.39 1.190E-03 7.505E-04 36.9%

18 11.84 7.86 7.837E-04 5.033E-04 35.8%

19 6.58 4.44 5.158E-04 3.364E-04 34.8%

21 4.02 2.72 3.236E-04 2.129E-04 34.2%

22 6.63 4.48 5.104E-04 3.330E-04 34.8%

Total 97.86 65.02 6.714E-03 4.324E-03 35.6%

V - 68
Table V-26

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the Central Phoenix Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

0 1.90 1.32 7.549E-05 5.230E-05 30.7%

1 0.99 0.74 5.184E-05 3.687E-05 28.9%

6 1.69 1.18 6.873E-05 4.797E-05 30.2%

7 0.99 0.74 5.254E-05 3.730E-05 29.0%

10 0.88 0.64 4.939E-05 3.485E-05 29.4%

11 2.01 1.41 7.319E-05 5.123E-05 30.0%

12 4.01 2.91 1.706E-04 1.166E-04 31.7%

13 7.52 5.04 2.448E-04 1.625E-04 33.6%

14 7.28 4.96 2.265E-04 1.520E-04 32.9%

15 4.33 3.04 1.657E-04 1.121E-04 32.3%

16 4.27 3.13 1.737E-04 1.192E-04 31.4%

17 2.29 1.60 8.494E-05 5.855E-05 31.1%

18 2.21 1.55 7.971E-05 5.545E-05 30.4%

Total 40.39 28.25 1.517E-03 1.037E-03 31.7%

V - 69
Table V-27

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the Durango Complex Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

11 1.99 1.37 1.340E-04 9.011E-05 32.8%

12 3.69 2.55 2.267E-04 1.543E-04 31.9%

13 3.12 2.15 1.876E-04 1.281E-04 31.7%

14 8.02 5.49 4.672E-04 3.093E-04 33.8%

15 9.84 7.07 4.992E-04 3.379E-04 32.3%

16 5.62 3.79 3.247E-04 2.160E-04 33.5%

17 2.47 1.72 1.619E-04 1.110E-04 31.4%

Total 34.74 24.13 2.001E-03 1.347E-03 32.7%

V - 70
Table V-28

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the Greenwood Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

12 1.05 0.77 5.872E-05 4.191E-05 28.6%

13 1.03 0.80 6.482E-05 4.701E-05 27.5%

14 3.03 2.16 1.618E-04 1.110E-04 31.4%

15 2.34 1.75 1.266E-04 8.868E-05 30.0%

Total 7.45 5.49 4.119E-04 2.886E-04 29.9%

V - 71
Table V-29

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the Higley Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

10 0.74 0.55 6.103E-05 4.481E-05 26.6%

11 3.00 2.05 1.944E-04 1.330E-04 31.6%

12 2.15 1.54 1.805E-04 1.270E-04 29.6%

13 2.41 1.69 1.824E-04 1.268E-04 30.4%

14 5.61 3.83 2.282E-04 1.553E-04 31.9%

15 5.70 3.98 2.113E-04 1.442E-04 31.8%

16 5.65 3.90 2.065E-04 1.403E-04 32.1%

17 1.50 1.11 6.687E-05 4.791E-05 28.4%

Total 26.76 18.64 1.331E-03 9.195E-04 30.9%

V - 72
Table V-30

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the West Phoenix Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

11 0.65 0.53 2.164E-05 1.680E-05 22.4%

12 1.78 1.33 5.329E-05 3.930E-05 26.2%

13 3.35 2.45 8.177E-05 5.933E-05 27.4%

14 4.27 3.08 1.123E-04 8.105E-05 27.8%

15 1.63 1.21 4.623E-05 3.396E-05 26.5%

Total 11.67 8.60 3.152E-04 2.304E-04 26.9%

V - 73
Table V-31

Base Case 2007 and Controlled 2012 High Wind PM-10 Emissions Inventories

for June 6, 2007 Design Day at the West 43rd Avenue Monitor

High Wind

Hour

Un-weighted Emissions

(tons) 

Distance-Weighted Emissions

(tons/feet from monitor)

% Reduction

of Weighted

Emissions 2007 2012 2007 2012

0 2.29 1.59 2.064E-04 1.388E-04 32.8%

5 3.31 2.29 2.894E-04 1.924E-04 33.5%

6 5.05 3.43 4.359E-04 2.860E-04 34.4%

10 3.44 2.38 2.835E-04 1.898E-04 33.1%

11 6.67 4.51 4.937E-04 3.237E-04 34.4%

12 6.02 4.06 5.697E-04 3.704E-04 35.0%

13 5.66 3.82 4.721E-04 3.088E-04 34.6%

14 9.67 6.48 6.830E-04 4.425E-04 35.2%

15 13.99 9.12 9.717E-04 6.168E-04 36.5%

16 9.67 6.48 6.630E-04 4.304E-04 35.1%

17 5.10 3.45 4.285E-04 2.812E-04 34.4%

18 4.94 3.34 3.857E-04 2.526E-04 34.5%

Total 75.81 50.97 5.883E-03 3.833E-03 34.8%

V - 74
Low Wind Inventories

Even though high wind design days are being modeled for this attainment demonstration,

there are still several hours, if not the majority of hours, in the design day when winds are

not high enough to produce windblown dust. Emissions from these hours contribute to the

design day value and need to be accounted for. Significant reductions from the control

measures in this plan have also occurred during low wind or stagnant conditions, so much

so that a stagnant PM-10 exceedance has not been seen since 2007 in the nonattainment

area.

The success of the low wind measures in this plan negates the need to develop complex

design day-specific emission inventories. But rather, annual low wind emissions can

simply be assigned to the land uses within each of the three low wind domains. The

difference in 2007 and 2012 low wind inventories provide the benefits of the measures in

this plan under low wind or stagnant conditions.

Initially, an investigation was made to see if the low wind inventory for the nonattainment

area as a whole could be used instead of spatially unique low wind domains. However,

because the nonattainment area is so large, substantial differences in the distribution of

land uses within the nonattainment area provide for drastically different mix of PM-10

sources throughout sub-areas of the nonattainment area. As such, it became apparent

that low wind emissions needed to be estimated for the areas immediately surrounding the

modeled monitors in order to accurately reflect the benefits of the control measures at

each monitor in the attainment demonstrations.

Low wind emissions are assigned to each of the three domains based upon land use

distribution within each of the domains. The values for the low wind emissions are taken

from Chapter Five of this Plan (the development of those emissions are explained in

Chapters II through III of this TSD). As a first step, the 2007 base and 2012 controlled low

wind inventories are assigned to the PM-10 nonattainment area as a whole. After the

allocation is complete, the allocated emissions are divided by the number of acres in each

land use to produce an annual tons/acre rate which can then be applied to the land uses

in each of the three low wind domains to estimate the low wind emissions in each domain. 

Table V-32 lists the low wind emission categories and the land uses to which those

emissions are allocated and Table V-33 lists the resulting tons/acre annual PM-10

emission rate for the PM-10 nonattainment area. Tables V-34 through V-36 display the

resulting low wind emissions in each of the three low wind domains.

V - 75
Table V-32

Annual Low Wind PM-10 Emission Inventory Allocated by Land Use Category

Source Category 2007 Emissions

(tons)

2012 Emissions

(tons)

Land Use Category

POINT 158.53 134.59 Industrial

AREA

Residential Fuel Combustion 514.20 535.25 Residential

Commercial Fuel Combustion 283.26 294.85 Commercial

Industrial Fuel Combustion 478.48 498.06 Industrial

Commercial Cooking 974.17 1,014.05 Commercial

Construction 16,106.11 3,731.54 Construction

Tilling, Harvesting, Cotton Ginning 936.27 893.20 Agriculture

Travel on Unpaved Farm Roads 768.69 731.03 Agriculture

Livestock 260.95 260.95 Agriculture

Travel on Unpaved parking Lots 2,3750.50 2,472.74 Vacant/Open

Offroad Recreational Vehicles 2,138.74 2,226.28 Vacant/Open

Leaf Blowers 877.98 913.91 Residential

Fires 496.71 496.71 Vacant/Open

Mining/Quarrying 561.81 255.62 Industrial

Travel on Industrial Haul Roads 770.71 350.67 Industrial

Other Industrial Sources 1,032.62 876.65 Industrial

NONROAD

Aircraft 193.54 145.50 Transportation

Airport Ground Support Equipment 28.64 19.90 Transportation

Locomotives 34.16 34.16 Transportation

Agricultural Equipment 15.37 13.60 Agriculture

Commercial Equipment 119.54 105.78 Commercial

Construction & Mining Equipment 1,269.88 1,123.64 Constr./Indust. 50/50

Industrial Equipment 103.04 91.18 Industrial

Lawn & Garden Equipment 185.95 164.53 Residential

Pleasure Craft 7.13 6.31 Vacant/Open

Railway Maintenance Equipment 1.15 1.02 Transportation

Recreation Vehicles 7.80 6.90 Vacant/Open

ONROAD

Exhaust 2,943.36 1,407.06 Transportation

Tire Wear 245.80 261.41 Transportation

Brake Wear 727.66 787.25 Transportation

Paved Roads 7,749.01 8,421.72 Transportation

Unpaved Roads 10,217.66 10,312.22 See Note

TOTAL 52,584.31 38,588.59 N/A

Note: Unpaved roads are allocated based upon the land uses that they are nearest to: Residential 26%,

Commercial 3%, Agriculture 13%, Vacant/Open 45%, Industrial 2% and Construction 11%.

V - 76
Table V-33

Annual Low Wind PM-10 Tons per Acre Emission Rates in the 

Nonattainment Area

Land Use Acres 2007 Tons 2012 Tons 2007 Tons/Acre 2012 Tons/Acre

Residential 435,720 4,235 4,295 9.72E-03 9.86E-03

Commercial 123,742 1,684 1,724 1.36E-02 1.39E-02

Agriculture 133,761 3,310 3,239 2.47E-02 2.42E-02

Vacant/Open 1,026,817 9,624 9,849 9.37E-03 9.59E-03

Transportation 28,856 11,923 11,078 4.13E-01 3.84E-01

Industrial 54,364 3,944 2,975 7.25E-02 5.47E-02

Construction* 43,795 17,865 5,428 4.08E-01 1.24E-01

TOTAL 1,847,054 52,584 38,588 2.86E-02 2.09E-02

*Construction acreage comes from Maricopa County Air Quality Department permit records for the year 2007. 

Only locations that were verifiable were included in the acreage total.

Table V-34

Annual Base Case 2007 and Controlled 2012 Low Wind PM-10 Emissions

Inventories for the Salt River Area Low Wind Domain

Land Use Acres

2007 Emissions

(tons)

2012 Emissions

(tons) % Reduction

Residential 6,296 61.19 62.05 (1.4%)

Commercial 4,508 61.34 62.81 (2.4%)

Agriculture 1,180 29.19 28.57 2.1%

Vacant/Open 2,984 27.97 28.62 (2.3%)

Transportation 405 167.28 155.42 7.1%

Industrial 6,410 465.10 350.77 24.6%

Construction 1,073 437.70 132.98 69.6%

Total 22,856 1,249.76 821.23 34.3%

V - 77
Table V-35

Annual Base Case 2007 and Controlled 2012 Low Wind PM-10 Emissions

Inventories for the Central City Low Wind Domain

Land Use Acres

2007 Emissions

(tons)

2012 Emissions

(tons) % Reduction

Residential 12,161 118.19 119.87 (1.4%)

Commercial 6,419 87.33 89.43 (2.4%)

Agriculture 0 0.00 0.00 0.0%

Vacant/Open 2,745 25.73 26.33 (2.3%)

Transportation 244 100.82 93.67 7.1%

Industrial 3,619 262.58 198.03 24.6%

Construction 404 164.80 50.07 69.6%

Total 25,592 759.46 577.41 24.0%

Table V-36

Annual Base Case 2007 and Controlled 2012 Low Wind PM-10 Emissions

Inventories for the Higley Low Wind Domain

Land Use Acres

2007 Emissions

(tons)

2012 Emissions

(tons) % Reduction

Residential 4,216 40.97 41.55 (1.4%)

Commercial 1,123 15.28 15.65 (2.4%)

Agriculture 1,865 46.15 45.17 2.1%

Vacant/Open 1,774 16.62 17.01 (2.3%)

Transportation 389 160.74 149.34 7.1%

Industrial 36 2.58 1.95 24.6%

Construction 765 312.06 94.81 69.6%

Total 10,167 594.41 365.49 38.5%

V - 78
CONTROL MEASURE ANALYSIS

Under rollback modeling, the reductions achieved by the control measures are reflected

as a comparison between the base case (2007) and controlled case (2012) inventories. 

Calculation of the emission reductions associated with these control measures for the

entire nonattainment area are presented in Chapters II and III of this TSD, as part of the

requirement to show five percent annual reductions in PM-10 emissions. 

Since high wind days are being modeled for this attainment demonstration, both high wind

and low wind inventories were developed to compare the effectiveness of the control

measures in this plan. For the high wind hours, reductions between the 2007 and 2012

inventories is solely due to the benefits of the control measures in this plan (increased rule

effectiveness), as land use is conservatively held constant between 2007 and 2012. No

adjustment for economic growth or recession has been applied to the high wind

inventories. These reductions have been shown as part of the high wind inventory tables

presented earlier (Tables V-25 through V-31). Although no credit has been taken, in

practice, land use conversion has also reduced PM-10 emissions within the high wind

domains, as construction activity has been limited due to the economic recession and as

agricultural land within the PM-10 area slowly converts to other uses. 

The reductions seen during the low wind hours are a result of both the control measures

and economic growth factors. Because of the large size of the nonattainment area, the

reductions of PM-10 emissions between the base case 2007 and controlled case 2012

inventories were calculated for three low wind domains within the nonattainment area. 

These reductions have been shown in Tables V-34 through V-36 as part of the discussion

of the creation of the low wind inventories.

V - 79
DEMONSTRATION OF ATTAINMENT

As discussed earlier in the Chapter, May 4, 2007 was selected as the high wind design

day to demonstrate attainment in the Salt River area, where the West 43rd Avenue monitor

alone had exceeded the 24-hour PM-10 standard. June 6, 2007 was chosen as the high

wind design day for the entire nonattainment area when two monitors in the nonattainment

area exceeded on this date (West 43rd Avenue and Higley). The control measures in this

plan are designed to reduce PM-10 emissions and their resulting concentrations to the

point where the design days can be shown to attain the standard. 

Rollback modeling assumes a linear relationship between PM-10 emissions sources and

their contribution to observed ambient PM-10 concentrations. Hours where the wind

speeds are low (< 12 mph), limit the emissions sources to those within the predetermined

low wind domain. Because all of the low wind sources are within a few miles of the

modeled monitor, all sources are weighted equally. During high wind hours, PM-10

emission sources follow the back trajectory of the prevailing winds at the monitor, forming

a high wind domain whose distance from the monitor stretches back based upon the

magnitude of the wind speeds. This creates high wind domains that can be over 20 miles

in length. To account for the distance of the windblown PM-10 sources from the modeled

monitor, these sources are weighted by their relative distance to the impacted monitor.

The reductions observed between the base case 2007 and controlled case 2012 low

inventory and the high wind (distance-weighted) inventory provides the expected

reductions of concentrations at the impacted monitor. Holding background values

constant, the reductions seen in the inventories are applied to the low and high wind hourly

concentrations of the design day to demonstrate that the control measures in the plan will

achieve attainment. Attainment in 2012 has been shown for both the May 4, 2007 and

June 6, 2007 design days. Results of the attainment demonstrations are presented in

Tables V-37 through V-44. 

V - 80
Table V-37

2012 Attainment Demonstration 

High Wind Design Day (May 4, 2007) at the West 43rd Avenue Monitor

Hour Wind

Speed

(mph)

May 4, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 2.5 25.9 14.9 22.1

1 1.4 19.8 14.9 18.1

2 0.4 27.0 14.9 22.8

3 5.5 31.5 14.9 25.8

4 6.7 50.7 14.9 38.4

5 8.5 82.7 14.9 59.4

6 7.2 117.3 14.9 82.2

7 4.9 71.9 14.9 52.3

8 4.5 73.5 14.9 53.4

9 9.2 73.0 14.9 53.1

10 9.4 144.2 14.9 99.9

11 10.6 147.0 14.9 101.7

12 13.4 196.6 21.9 137.5

13 17.6 521.0 21.9 346.4

14 17.4 451.6 21.9 300.6

15 18.7 449.9 21.9 295.8

16 17.7 311.2 21.9 206.7

17 19.4 570.0 21.9 367.7

18 17.6 357.2 21.9 237.2

19 15.5 204.0 21.9 140.7

20 9.8 174.7 14.9 119.9

21 13.6 148.8 21.9 105.4

22 15.6 281.1 21.9 191.0

23 11.6 205.6 14.9 140.2

24-Hour Avg. 197.3 134.1

Note: High wind hours highlighted in bold italics.

V - 81
Table V-38

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the Central Phoenix Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 12.5 138.5 21.9 102.7

1 13.1 176.2 21.9 131.6

2 8.6 133.6 14.9 105.1

3 8.0 109.7 14.9 86.9

4 10.9 92.9 14.9 74.2

5 10.3 81.5 14.9 65.5

6 12.4 99.6 21.9 76.1

7 12.8 104.0 21.9 80.2

8 11.1 80.2 14.9 64.5

9 11.3 73.2 14.9 59.2

10 12.1 69.6 21.9 55.6

11 13.9 96.1 21.9 73.8

12 15.3 106.2 21.9 79.5

13 15.4 150.5 21.9 107.3

14 16.9 211.2 21.9 148.9

15 17.8 255.7 21.9 180.1

16 15.7 111.7 21.9 83.5

17 14.0 71.0 21.9 55.7

18 14.0 74.4 21.9 58.4

19 11.9 72.5 14.9 58.7

20 11.1 59.8 14.9 49.0

21 11.7 70.6 14.9 57.2

22 8.8 63.0 14.9 51.5

23 8.5 66.9 14.9 54.4

24-Hour Avg. 107.0 81.7

Note: High wind hours highlighted in bold italics.

V - 82
Table V-39

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the Durango Complex Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 8.9 132.6 14.9 92.2

1 6.3 166.4 14.9 114.4

2 5.0 133.6 14.9 92.9

3 1.0 112.7 14.9 79.2

4 2.6 124.4 14.9 86.8

5 7.3 101.4 14.9 71.7

6 9.1 164.5 14.9 113.2

7 8.7 113.4 14.9 79.6

8 10.5 93.6 14.9 66.6

9 11.2 86.3 14.9 61.8

10 11.9 83.3 14.9 59.8

11 12.5 130.3 21.9 94.8

12 13.9 168.1 21.9 121.4

13 13.5 202.7 21.9 145.4

14 15.7 405.5 21.9 275.9

15 17.9 398.1 21.9 276.5

16 14.5 119.9 21.9 87.1

17 12.9 70.0 21.9 54.9

18 10.3 53.9 14.9 40.5

19 8.9 57.0 14.9 42.6

20 6.4 61.1 14.9 45.3

21 7.5 83.0 14.9 59.6

22 6.3 67.8 14.9 49.7

23 5.2 79.6 14.9 57.4

24-Hour Avg. 133.7 94.6

Note: High wind hours highlighted in bold italics.

V - 83
Table V-40

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the Greenwood Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 8.1 138.4 14.9 108.8

1 5.7 159.9 14.9 125.1

2 4.9 123.4 14.9 97.4

3 2.9 105.2 14.9 83.5

4 2.1 105.6 14.9 83.8

5 5.4 86.5 14.9 69.3

6 6.7 112.6 14.9 89.2

7 7.7 103.8 14.9 82.5

8 8.3 77.9 14.9 62.8

9 10.0 79.0 14.9 63.6

10 11.0 74.7 14.9 60.3

11 10.8 103.2 14.9 82.0

12 12.7 172.2 21.9 129.2

13 12.6 194.6 21.9 147.1

14 15.4 442.1 21.9 310.3

15 13.9 240.6 21.9 175.1

16 11.9 93.5 14.9 74.6

17 11.7 96.9 14.9 77.2

18 11.4 82.5 14.9 66.3

19 8.7 68.3 14.9 55.5

20 7.4 61.3 14.9 50.2

21 7.0 67.9 14.9 55.2

22 5.1 63.5 14.9 51.8

23 4.0 68.3 14.9 55.5

24-Hour Avg. 121.7 94.0

Note: High wind hours highlighted in bold italics.

V - 84
Table V-41

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the Higley Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 7.4 39.6 14.9 30.1

1 5.8 72.9 14.9 50.6

2 8.8 135.2 14.9 88.9

3 9.0 130.9 14.9 86.2

4 9.1 104.9 14.9 70.3

5 7.4 96.4 14.9 65.0

6 9.4 113.4 14.9 75.5

7 9.4 90.9 14.9 61.6

8 10.8 187.2 14.9 120.9

9 11.6 195.1 14.9 125.7

10 14.6 580.2 21.9 431.9

11 15.2 379.0 21.9 266.3

12 17.6 568.8 21.9 406.7

13 15.3 408.1 21.9 290.5

14 15.8 387.9 21.9 271.1

15 15.6 268.9 21.9 190.5

16 15.3 167.5 21.9 120.8

17 13.5 96.4 21.9 75.3

18 10.1 45.2 14.9 33.5

19 6.9 50.7 14.9 36.9

20 6.6 43.1 14.9 32.2

21 7.1 60.5 14.9 42.9

22 2.9 55.7 14.9 40.0

23 3.2 66.9 14.9 46.9

24-Hour Avg. 181.1 127.5

Note: High wind hours highlighted in bold italics.

V - 85
Table V-42

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the State Super Site Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 7.6 99.3 14.9 79.0

1 6.3 149.6 14.9 117.3

2 5.4 112.2 14.9 88.8

3 5.4 95.8 14.9 76.4

4 6.7 92.4 14.9 73.8

5 7.2 80.6 14.9 64.8

6 7.2 80.2 14.9 64.5

7 6.5 82.7 14.9 66.4

8 7.2 63.5 14.9 51.8

9 6.7 60.8 14.9 49.8

10 6.9 53.6 14.9 44.3

11 9.4 65.5 14.9 53.4

12 8.9 77.8 14.9 62.7

13 9.8 107.8 14.9 85.5

14 10.5 142.1 14.9 111.6

15 11.4 109.4 14.9 86.7

16 10.1 62.3 14.9 50.9

17 9.2 54.4 14.9 44.9

18 11.2 57.5 14.9 47.3

19 9.6 53.9 14.9 44.5

20 7.8 60.9 14.9 49.9

21 6.3 62.5 14.9 51.1

22 3.8 55.1 14.9 45.5

23 3.6 54.8 14.9 45.2

24-Hour Avg. 80.6 64.8

 

V - 86
Table V-43

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the West Phoenix Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 7.1 134.4 14.9 105.7

1 7.8 164.9 14.9 128.9

2 8.4 123.8 14.9 97.7

3 4.2 106.1 14.9 84.2

4 5.1 99.1 14.9 78.9

5 6.1 84.4 14.9 67.7

6 8.5 94.4 14.9 75.3

7 10.3 102.9 14.9 81.8

8 8.7 75.2 14.9 60.7

9 8.6 70.3 14.9 57.0

10 8.8 62.1 14.9 50.8

11 12.1 122.2 21.9 99.7

12 13.6 169.6 21.9 130.8

13 15.1 256.6 21.9 192.2

14 15.1 259.8 21.9 193.6

15 13.5 132.1 21.9 102.9

16 12.0 88.2 14.9 70.6

17 11.7 71.9 14.9 58.2

18 10.0 66.7 14.9 54.3

19 9.3 65.1 14.9 53.1

20 9.1 66.7 14.9 54.3

21 6.8 67.3 14.9 54.7

22 5.3 62.6 14.9 51.2

23 4.8 63.7 14.9 52.0

24-Hour Avg. 108.8 85.7

Note: High wind hours highlighted in bold italics.

V - 87
Table V-44

2012 Attainment Demonstration 

High Wind Design Day (June 6, 2007) at the West 43rd Avenue Monitor

Hour Wind

Speed

(mph)

June 6, 2007 PM-10

Concentration

(μg/m3

)

 Background

Concentration

(μg/m3

)

2012 Controlled PM-10

Concentration

(μg/m3

)

0 13.3 175.1 21.9 124.9

1 9.9 177.0 14.9 121.4

2 9.1 150.0 14.9 103.7

3 7.8 115.5 14.9 81.0

4 10.6 145.0 14.9 100.4

5 14.5 318.0 21.9 218.8

6 14.9 267.2 21.9 182.9

7 11.4 208.1 14.9 141.8

8 11.3 131.4 14.9 91.4

9 12.0 152.0 14.9 105.0

10 13.8 180.8 21.9 128.3

11 16.0 438.3 21.9 294.9

12 16.6 449.1 21.9 299.6

13 15.1 394.9 21.9 265.9

14 17.6 643.1 21.9 424.3

15 18.1 662.3 21.9 428.4

16 17.0 237.5 21.9 161.8

17 14.5 92.3 21.9 68.1

18 14.9 77.9 21.9 58.6

19 12.0 56.1 14.9 42.0

20 8.8 87.3 14.9 62.5

21 9.3 98.1 14.9 69.6

22 7.0 82.6 14.9 59.4

23 6.8 78.3 14.9 56.6

24-Hour Avg. 225.7 153.8

Note: High wind hours highlighted in bold italics.

V - 88
APPENDIX B

EXHIBIT 2:

Calculation of Benefits from PM-10 Certified Street

Sweepers Purchased with CMAQ Funds in 2001-2009
CMAQ Funded PM-10 Certified Street Sweepers Purchased in 2001-2009

Sweeper AADT Per Lane Lane Cycle Cycle Total Reduction Be # Agency Requesting Sweeper Lane MIles Old Miles New LenOld LenNew Replace Expand Incr Freq Process Reduction by Unit Usa

1 Apache Junction 832 98 118 45 30 0.41 1.20 1.61 1.61 4 Chandler 5,260 131 131 14 14 32.30 0.22 32.51 32.51 6 Chandler 8,313 165 165 7 7 118.53 0.54 119.08 119.08 8 El Mirage 1,469 129 108 30 15 -1.13 5.83 4.70 4.70 9 Fort McDowell 1,500 21 21 30 30 0.69 0.02 0.71 0.71 

21 Litchfield Park 4,518 12 12 30 30 1.19 0.01 1.20 5.34 

2,259 23 28 14 14 2.44 0.89 0.05 3.37 

244 35 50 14 14 0.40 0.29 0.08 0.77 

23 Mesa 229 342 342 38 38 1.35 0.21 1.56 1.56 24 Paradise Valley 10,000 20 20 90 30 1.46 4.90 0.02 6.37 15.41 

7,000 22.5 22.5 90 30 1.15 3.86 0.02 5.02 3,000 18 18 90 45 0.39 0.66 0.01 1.06 1,000 147 147 90 45 1.07 1.80 0.08 2.95 

26 Peoria 4,500 53.4 53.4 25 25 6.31 0.05 6.36 7.88 

1,000 18 18 35 35 0.34 0.01 0.35 

500 116.8 116.8 35 35 1.09 0.08 1.17 

27 Phoenix 4,205 302 302 21 14 33.33 33.33 33.33 28 Phoenix 4,205 302 302 21 14 33.33 33.33 33.33 29 Phoenix 4,205 302 302 21 14 33.33 33.33 33.33 30 Phoenix 4,205 302 302 21 14 33.33 33.33 33.33 31 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 32 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 33 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 34 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 35 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 36 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 37 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 38 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 39 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 40 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 41 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 42 Phoenix 4,205 302 302 14 14 59.52 0.50 60.02 60.02 43 Scottsdale 8,450 49 49 7 7 35.78 0.16 35.94 37.45 

150 310 310 25 25 1.22 0.29 1.51 

44 Scottsdale 7,100 101 101 7 7 61.97 0.33 62.30 62.33 

350 4 4 42 42 0.02 0.00 0.02 

45 Scottsdale 7,000 73 73 7 7 44.16 0.24 44.40 46.54 

2,000 11 11 21 21 0.69 0.01 0.70 

350 240 240 42 42 1.31 0.13 1.44 

49 Tempe 6,600 111.75 111.75 21 5 23.05 94.15 0.51 117.71 133.09 

4,750 26.75 26.75 21 10 3.97 7.34 0.06 11.37 

800 153.75 153.75 21 21 3.84 0.17 4.01 

50 Tempe 6,600 111.75 111.75 21 5 23.05 94.15 0.51 117.71 133.09 

4,750 26.75 26.75 21 10 3.97 7.34 0.06 11.37 

800 153.75 153.75 21 21 3.84 0.17 4.01 

52 Youngtown 1,492 26 26 90 30 0.28 0.95 0.02 1.25 1.25 53 Queen Creek 1,365 20 20 30 15 0.60 1.00 0.03 1.63 2.21 

910 6 6 30 15 0.12 0.20 0.01 0.33 

68 46 46 30 15 0.07 0.12 0.07 0.25 

54 Chandler 1,492 60 60 30 30 1.96 0.05 2.00 5.92 

291 548 548 30 30 3.49 0.42 3.91 

55 Glendale 5,706 175 175 12 12 54.60 0.34 54.94 64.60 

910 110 110 15 15 4.38 0.17 4.55 

PM-10 Emission Reductions (kg/day)

1
CMAQ Funded PM-10 Certified Street Sweepers Purchased in 2001-2009

Sweeper AADT Per Lane Lane Cycle Cycle Total Reduction Be # Agency Requesting Sweeper Lane MIles Old Miles New LenOld LenNew Replace Expand Incr Freq Process Reduction by Unit Usa

PM-10 Emission Reductions (kg/day)

228 445 445 15 15 4.43 0.68 5.11 

56 Tempe 6,006 12 12 7 5 6.23 2.16 0.06 8.45 11.11 

4,323 6 6 10 10 1.70 0.01 1.72 

728 40 40 21 21 0.91 0.04 0.95 

58 Surprise 6,066 6 17 28 15 0.85 2.63 3.52 0.03 7.02 8.08 

218 6 43 28 15 0.03 0.32 0.32 0.07 0.74 

67 46 103 42 28 0.05 0.10 0.09 0.08 0.32 

59 Surprise 6,066 112 123 28 15 2.63 25.46 28.09 28.90 

218 7 44 28 15 0.32 0.33 0.65 

67 15 72 42 28 0.10 0.06 0.16 

60 Peoria 4,095 242 248 25 25 1.08 1.08 3.96 

910 91 111 30 30 0.67 0.67 601 576 676 30 30 2.21 2.21 

61 Buckeye 3,640 6 6 7 7 1.89 0.02 1.91 3.04 

776 10 10 7 7 0.67 0.03 0.70 194 40 40 14 14 0.36 0.07 0.43 

62 Gila River IC 6,825 6 6 7 7 3.54 0.02 3.56 4.56 

444 24 24 7 7 0.92 0.08 1.00 

63 Gila River IC 2,730 4 4 7 7 0.94 0.01 0.96 1.19 

228 10 10 7 7 0.20 0.03 0.23 

64 Gila River IC 3,640 16 16 25 14 2.02 2.02 2.54 

375 40 40 25 14 0.52 0.52 

65 Gila River IC 228 4 4 25 14 0.03 0.03 0.15 

118 30 30 25 14 0.12 0.12 

66 El Mirage 3,550 4 11 30 10 0.91 2.87 3.78 6.42 

1,755 12 12 30 12 1.16 1.16 

910 44 44 30 15 1.47 1.47 

67 Phoenix 4,205 302 302 21 14 33.33 33.33 66.66 

4,205 302 302 21 14 33.33 33.33 

68 Phoenix 4,205 302 302 21 14 33.33 33.33 66.66 

4,205 302 302 21 14 33.33 33.33 

69 Tempe - Arterials 6,006 12 12 12 12 3.94 0.02 3.96 6.63 

Tempe - Collectors 4,323 6 6 10 10 1.70 0.01 1.72 Tempe - Res Streets 728 40 40 21 21 0.91 0.04 0.95 

70 Chandler - Collectors 898 46 46 30 30 0.90 0.04 0.94 2.22 

Chandler - Res Streets 106 414 414 30 30 0.96 0.32 1.28 

71 Chandler - Collectors 1,356 43 43 30 30 1.28 0.03 1.31 3.37 

Chandler - Res Streets 208 387 387 30 30 1.76 0.30 2.06 

72 Apache Junction - Arterials 3,458 28.25 28.25 20 20 3.21 0.03 3.24 4.16 

Apache Junction - Collectors 496 10.75 10.75 20 20 0.17 0.01 0.19 Apache Junction - Res Streets 137 61.5 61.5 20 20 0.28 0.07 0.35 

Apache Junction - Other mid sect 1,274 9 9 20 20 0.38 0.01 0.39 

73 Queen Creek - Arterials 1,365 0 9.7 15 15 0.97 0.97 1.46 

Queen Creek - Collectors 455 0 6.8 15 15 0.23 0.23 Queen Creek - Res Streets 228 0 31.3 30 30 0.26 0.26 

74 Phoenix - Arterials 4,488 450 450 14 7 144.23 144.23 221.40 

Phoenix - Collector/Res Streets 2,401 450 450 14 7 77.17 77.17 

75 Phoenix - Arterials 4,488 450 450 14 7 144.23 144.23 221.40 

Phoenix - Collector/Res Streets 2,401 450 450 14 7 77.17 77.17 

76 Scottsdale - Arterials 3,185 0 260 30 30 30.43 30.43 30.43 77 Fountain Hills- Arterials 4,550 85 85 15 15 16.92 0.13 17.05 25.80 

Fountain Hills - Collectors 1,820 140 140 45 30 3.72 3.12 0.11 6.94 Fountain Hills - Res Streets 273 350 350 60 45 1.05 0.59 0.18 1.81 

2
CMAQ Funded PM-10 Certified Street Sweepers Purchased in 2001-2009

Sweeper AADT Per Lane Lane Cycle Cycle Total Reduction Be # Agency Requesting Sweeper Lane MIles Old Miles New LenOld LenNew Replace Expand Incr Freq Process Reduction by Unit Usa

PM-10 Emission Reductions (kg/day)

79 Gilbert - Arterials - 9,087 269 506 15 15 158.28 158.28 238.43 

Gilbert - Collector/Res Streets 2,730 0 799 30 30 80.15 80.15 

80 Gilbert - Arterials 9,087 269 506 15 15 158.28 158.28 238.43 

Gilbert - Collector/Res Streets 2,730 0 799 30 30 80.15 80.15 

81 Buckeye - Arterials 1,593 0 24 7 7 5.74 5.74 5.74 82 ADOT - Freeway 30,030 175 250 14 7 55.74 168.50 224.23 301.18 

ADOT - Other Frontage Roads 7,818 375 500 14 14 76.95 76.95 

83 ADOT - Freeway 30,030 175 250 14 7 55.74 168.50 224.23 301.18 

ADOT - Other Frontage Roads 7,818 375 500 14 14 76.95 76.95 

84 Surprise- Arterials 8,964 120 120 20 15 19.76 19.76 20.15 

Surprise- Collectors 198 16 40 28 20 0.19 0.12 0.31 Surprise - Res Streets 61 36 67 120 45 0.02 0.06 0.08 

85 Guadalupe - Collectors 5,678 5 5 1 1 0.00 0.52 

Guadalupe - Res Streets 578 25 25 4 2 0.52 0.52 

86 Williams Gateway- Arterials 410 12 12 14 5 0.50 0.50 0.50 87 Mesa - Collectors 1,759 35 35 40 40 1.01 0.02 1.03 1.86 

Mesa - Res Streets 200 215 215 40 40 0.71 0.12 0.83 

88 Mesa - Collectors 1,759 35 35 40 40 1.01 0.02 1.03 1.86 

Mesa - Res Streets 200 215 215 40 40 0.71 0.12 0.83 

89 Avondale - Collectors 4,550 44 44 7 7 17.30 0.14 17.45 27.85 

Avondale - Res Streets 910 127 127 7 7 9.99 0.42 10.40 

90 Chandler Airport - Arterials 523 4 4 5 5 0.20 0.02 0.21 2.61 

Chandler Airport - Collectors 91 1 1 5 5 0.01 0.00 0.01 Chandler Airport - Other 683 35 35 5 5 2.23 0.16 2.39 

91 Goodyear - Arterials 3,185 176 176 14 14 26.27 0.29 26.56 30.52 

Goodyear - Collectors 601 84 84 14 14 2.36 0.14 2.50 Goodyear - Res Streets 218 122 122 14 14 1.25 0.20 1.45 

92 Goodyear - Arterials - 2005 3,185 176 176 14 14 26.27 0.29 26.56 30.52 

Goodyear - Collectors 601 84 84 14 14 2.36 0.14 2.50 Goodyear - Res Streets 218 122 122 14 14 1.25 0.20 1.45 

93 Gilbert - Arterials 6,104 679 679 15 15 181.32 1.04 182.36 236.73 

Gilbert - Collectors 3,000 70 70 20 20 6.89 0.08 6.97 Gilbert - Res Streets 3,000 714 714 30 30 46.85 0.55 47.40 

94 Gilbert - Arterials 6,982 697 697 15 15 212.90 1.07 213.97 268.34 

Gilbert - Collectors 3,000 70 70 20 20 6.89 0.08 6.97 Gilbert - Res Streets 3,000 714 714 30 30 46.85 0.55 47.40 

95 Gilbert - Arterials 5,954 697 697 15 15 181.55 1.07 182.62 236.99 

Gilbert - Collectors 3,000 70 70 20 20 6.89 0.08 6.97 Gilbert - Res Streets 3,000 714 714 30 30 46.85 0.55 47.40 

96 Phoenix - Arterials 5,918 465 465 10 10 142.52 142.52 227.87 

Phoenix - Collector/Res Streets 3,167 460 460 14 14 85.36 85.36 

97 Phoenix - Arterials 5,918 465 465 10 10 142.52 142.52 205.40 

Phoenix - Collector/Res Streets 3,167 460 460 7 7 62.89 62.89 

100 Surprise - Arterials 10,000 54 54 20 3 85.52 85.52 85.52 101 Tempe - Arterials 6,600 48 48 12 6 23.11 23.11 33.73 

Tempe - Collectors 4,750 32 32 10 5 10.63 10.63 

102 Goodyear - Arterials 3,750 234 234 30 14 36.85 36.85 36.85 

Goodyear - Collectors 675 114 114 14 14 0.00 0.00 Goodyear - Res Streets 240 130 130 14 14 0.00 0.00 

103 Tolleson - Collectors 1,500 26 26 14 7 1.83 2.79 0.09 4.70 5.55 

Tolleson - Res Streets 250 26 26 14 7 0.30 0.46 0.09 0.85 

104 Mesa - Collectors 1,759 40 40 52 43 0.31 0.31 0.49 

Mesa - Res Streets 182 215 215 52 43 0.17 0.17 

3
CMAQ Funded PM-10 Certified Street Sweepers Purchased in 2001-2009

Sweeper AADT Per Lane Lane Cycle Cycle Total Reduction Be # Agency Requesting Sweeper Lane MIles Old Miles New LenOld LenNew Replace Expand Incr Freq Process Reduction by Unit Usa

PM-10 Emission Reductions (kg/day)

Mesa - Other (Alleys) 109 5 5 52 43 0.00 0.00 

105 Mesa Falcon Field - Arterials 1,320 7 7 7 7 0.80 0.02 0.82 0.82 106 Litchfield Park - Arterials 4,111 12 16 30 21 0.60 1.04 1.64 4.07 

Litchfield Park - Collectors 2,056 23 25 14 10 0.32 1.62 1.94 Litchfield Park - Res Streets 222 35 45 14 10 0.17 0.31 0.49 

107 Buckeye - Arterials 546 0 62 7 7 5.08 5.08 5.57 

Buckeye - Collectors 273 0 4 7 7 0.16 0.16 Buckeye - Res Streets 27 0 80 7 7 0.33 0.33 

108 Surprise - Arterials 2,093 48 48 16 7 8.16 8.16 8.97 

Surprise - Collectors 1,638 24 24 5 5 0.00 Surprise - Res Streets 455 0 48 30 30 0.80 0.80 

109 Queen Creek - Arterials 4,550 15 51 15 7 12.04 17.79 29.83 31.88 

Queen Creek - Collectors 2,730 0 5 15 7 1.00 1.05 2.05 

110 Gilbert - Arterials 4,572 256 256 15 15 51.20 0.39 51.59 85.82 

Gilbert - Collectors 2,275 300 300 15 15 29.86 0.46 30.32 Gilbert - Res Streets 228 340 340 15 15 3.38 0.52 3.91 

111 Gilbert - Arterials 4,576 256 256 15 15 51.25 0.39 51.65 85.87 

Gilbert - Collectors 2,275 300 300 15 15 29.86 0.46 30.32 Gilbert - Res Streets 228 340 340 15 15 3.38 0.52 3.91 

112 Chandler - Arterials 5,098 0 34.5 30 30 6.46 6.46 6.46 113 Cave Creek - Arterials 3,731 0 10 180 14 0.23 2.71 2.94 22.69 

Cave Creek - Collectors 1,593 0 20 180 30 0.20 0.98 1.17 Cave Creek - Res Streets 228 0 25 180 60 0.03 0.07 0.10 Cave Creek - Major Intersection 7,963 0 10 180 2 0.49 17.99 18.48 

114 Goodyear - Collectors 655 65 65 21 14 1.12 1.12 1.73 

Goodyear - Res Streets 237 99 99 21 14 0.61 0.61 

115 Fountain Hills - Arterials 4,550 85 85 15 15 16.92 0.13 17.05 31.59 

Fountain Hills - Collectors 1,820 140 140 45 30 3.72 3.12 0.11 6.94 Fountain Hills - Res Streets 273 350 350 60 45 1.05 0.59 0.18 1.81 Fountain Hills - Downtown 2,730 15 15 45 7 0.60 5.15 0.05 5.79 

120 Chandler - Arterials 7,745 66 66 14 14 29.95 29.95 32.83 

Chandler - Collectors 1,201 15 15 30 30 1.22 1.22 Chandler - Other 6,120 4 4 30 30 1.66 1.66 

121 Surprise - Arterials 6,461 0 31 15 15 14.72 14.72 26.71 

Surprise - Collectors 3,185 0 37 15 15 8.66 8.66 Surprise - Res Streets 546 0 166 30 30 3.33 3.33 

122 Avondale - Arterials 8,190 91 97 7 7 7.38 7.38 9.10 

Avondale - Collectors 1,820 41 43 14 14 0.29 0.29 Avondale - Res Streets 910 244 264 14 14 1.43 1.43 

123 Queen Creek - Arterials 3,640 29 46 15 7 4.55 12.84 17.38 17.46 

Queen Creek - Res Streets 68 29 58 30 30 0.07 0.07 

126 Mesa - Collectors 1,759 42 44 43 40 0.09 0.15 0.24 0.37 

Mesa - Res Streets 182 225 235 43 40 0.05 0.08 0.13 Mesa - Other 109 5 5 43 40 0.00 0.00 

127 Paradise Valley - Arterials 6,825 18 18 15 15 0.00 0.00 0.29 

Paradise Valley - Collectors 364 15 15 35 28 0.04 0.04 Paradise Valley- Res Streets 319 100 100 35 28 0.25 0.25 

131 Maricopa County - Arterials 364 0 534 14 14 15.31 15.31 24.51 

Maricopa County - Res Streets 364 0 367 16 16 9.20 9.20 

132 Maricopa County - Arterials 364 0 534 14 14 15.31 15.31 24.51 

Maricopa County - Res Streets 364 0 367 16 16 9.20 9.20 

133 ASU - Res Streets 2,527 17 29.32 1 1 4.76 7.86 0.67 13.29 21.25 

ASU - Pedestrian Paths 4,095 10.04 13.04 1 1 4.55 3.10 0.30 7.96 

4
CMAQ Funded PM-10 Certified Street Sweepers Purchased in 2001-2009

Sweeper AADT Per Lane Lane Cycle Cycle Total Reduction Be # Agency Requesting Sweeper Lane MIles Old Miles New LenOld LenNew Replace Expand Incr Freq Process Reduction by Unit Usa

PM-10 Emission Reductions (kg/day)

145 Scottsdale - Arterials 5,897 44 44 7 7 20.84 20.84 41.47 

Scottsdale - Collectors 3,898 62 62 7 7 19.41 19.41 Scottsdale - Res Streets 91 108 108 25 25 1.21 1.21 

Total purchased through December 31, 2009 2,756.22 919.95 1,570.24 25.35 5,271.77 5,271.77 

 Sweepers purchased 1/1/01-12/31/06 

 Sweepers purchased 1/1/07-12/31/09 

Notes:(1) Missing sweeper #s in column A represent units that were purchased with CMAQ funds, but were no longer in service as of December 31, 2009(2) EFs are based on the Jan 2011 AP-42 Paved Road equation; EFs for Arterials <10,000 ADT (0.71 g/mi) and >10,000 ADT (0.23 g/mi) were weighted by 2008 VMT to ob

(3) If Benefits with Usage Factor = 0.00, the sweeper is replacing an older PM-10 certified sweeper and no credit is taken

5
APPENDIX C
APPENDIX C

EXHIBIT 1:

Arizona Revised Statutes Listed in Table 4-1
ARIZONA REVISED STATUTES LISTED IN TABLE 4-1

9-500.04. Air quality control; definitions

A. The governing body of a city or town in area A or area B as defined in section

49-541 shall:

3. In area A, beginning on January 1, 2008, develop and implement plans to

stabilize targeted unpaved roads, alleys and unpaved shoulders on targeted arterials. The

plans shall address the performance goals, the criteria for targeting the roads, alleys and

shoulders, a schedule for implementation, funding options and reporting requirements. 

priority shall be given to the following:

(a) Unpaved roads with more than one hundred average daily trips.

(b) Unpaved shoulders on arterial roads and other road segments where vehicle

use on unpaved shoulders is evident or anticipated due to projected traffic volume.

5. In area A, in order to reduce particulate matter in ambient air:

(a) Beginning March 31, 2008, on any high pollution advisory day forecast by the

department of environmental quality prohibit employees or contractors of that city or town

from operating leaf blowers except while in vacuum mode and prohibit those employees

or contractors from blowing landscape debris into public roadways at any time.

(b) No later than March 31, 2008, adopt, implement and enforce an ordinance that

bans the blowing of landscape debris into public roadways at any time by any person.

6. In area A, no later than March 31, 2008, adopt or amend codes or ordinances

and, no later than October 1, 2008, commence enforcement of those codes or ordinances

as necessary to require that parking, maneuvering, ingress and egress areas at

developments other than residential buildings with four or fewer units are maintained with

one or more of the following dustproof paving methods:

(a) Asphaltic concrete.

(b) Cement concrete.

(c) Penetration treatment of bituminous material and seal coat of bituminous binder

and a mineral aggregate.

(d) A stabilization method approved by the city or town.

7. In area A, no later than March 31, 2008, adopt or amend codes or ordinances

and, no later than October 1, 2009, commence enforcement of those codes or ordinances

as necessary to require that parking, maneuvering, ingress and egress areas that are three

thousand square feet or more in size at residential buildings with four or fewer units are

maintained with a paving or stabilization method authorized by the city or town by code,

ordinance or permit.

8. In area A, no later than March 31, 2008, adopt or amend codes or ordinances as

necessary to restrict vehicle parking and use on unpaved or unstabilized vacant lots.

9. In area A, no later than March 31, 2008, require that new or renewed contracts

for street sweeping on city streets must be conducted with street sweepers that meet the

south coast air quality management district rule 1186 street sweeper certification

specifications for pick up efficiency and PM-10 emissions in effect on January 1, 2007.

H. Subsection A, paragraphs 5 through 8 of this section do not apply to any site that

1
has a permit issued by a control officer as defined in section 49-471 for the control of

fugitive dust from dust generating operations.

9-500.27. Off-road vehicle ordinance; applicability; violation; classification

A. No later than March 31, 2008, in area A, as defined in section 49-541, a city or

town shall adopt, implement and enforce an ordinance that prohibits the operation of any

vehicle, including an off-highway vehicle, an all-terrain vehicle or an off-road recreational

motor vehicle, on an unpaved surface that is not a public or private road, street or lawful

easement and that is closed by the landowner by rule or regulation of a federal agency, this

state, a county or a municipality or by proper posting if the land is private land.

B. This section does not apply to the operation of vehicles used in the normal

course of business or the normal course of government operations.

C. This section does not prohibit or preempt the enforcement of any similar

ordinance that is adopted by a city or town in area A, as defined in section 49-541, before

March 31, 2008 for purposes of dust abatement.

D. A person who violates an ordinance adopted pursuant to subsection A of this

section is guilty of a class 3 misdemeanor.

E. In addition to or in lieu of a fine pursuant to this section, a judge may order the

person to perform at least eight but not more than twenty-four hours of community

restitution or to complete an approved safety course related to the off-highway operation

of motor vehicles, or both.

11-871. Emissions control; no burn; exemptions; penalty

A. A county that contains any part of area A, as defined in section 49-541, shall

develop, implement, and enforce in area A, as defined in section 49-541, an ordinance

relating to residential wood burning restrictions, including a no burn restriction when

monitoring or forecasting by the department of environmental quality predicts the carbon

monoxide standard is likely to be exceeded.

B. On or before October 31, 2007, a county that contains any part of area A, as

defined in section 49-541, shall amend the ordinance prescribed by subsection A of this

section to include a no burn restriction for any high pollution advisory day forecast by the

department of environmental quality for particulate matter.

D. The ordinance shall provide that a person who violates an ordinance adopted

pursuant to this section is subject to:

4. The imposition of a civil penalty of two hundred fifty dollars for the fourth or any

subsequent violation.

11-877. Air quality control measures

A. In order to reduce particulate matter in ambient air, the board of supervisors of

any county that contains any portion of area A, as defined in section 49-541, shall develop,

implement and enforce in area A the following air quality control measures:

1. Beginning on the effective date of this section, prohibit employees or contractors

of that county from operating leaf blowers on any high pollution advisory day forecast by

the department of environmental quality except while in vacuum mode and prohibit those

employees or contractors from blowing landscape debris into public roadways at any time.

2. No later than March 31, 2008, adopt, implement and enforce an ordinance that

bans the blowing of landscape debris into public roadways at any time by any person.

3. No later than March 31, 2008, adopt, implement and enforce an ordinance that

2
prohibits the operation of leaf blowers except on surfaces that have been stabilized with

asphaltic concrete, cement concrete, hardscape, penetration treatment of bituminous

material and seal coat of bituminous binder and a mineral aggregate, decomposed granite

cover, crushed granite cover, aggregate cover, gravel cover, or grass or other continuous

vegetative cover, or any combination of those stabilizers.

B. This section does not apply to any site that has a permit issued by a control

officer as defined in section 49-471 for the control of fugitive dust from dust generating

operations.

28-1098. Vehicle loads; restrictions; civil penalties

A. For the purpose of highway safety or air pollution prevention, a person shall not

drive or move a vehicle on a highway unless the vehicle is constructed or loaded in a

manner to prevent any of its load from dropping, sifting, leaking or otherwise escaping from

the vehicle, except the following are permitted:

1. Sufficient sand may be dropped for the purpose of securing traction.

2. Water or another substance may be sprinkled on a roadway in cleaning or

maintaining the roadway.

3. Minor pieces of agricultural materials such as leaves and stems from agricultural

loads.

C. If a person is found in violation of this section and the violation:

1. Does not cause any damage or injury and is the person's:

(a) First violation in a sixty month period, the person is subject to a civil penalty of

not more than two hundred fifty dollars.

(b) Second or subsequent violation in a sixty month period, the person is subject

to a civil penalty of not more than three hundred fifty dollars.

49-424. Duties of department

The department shall:

11. Develop and disseminate air quality dust forecasts for the Maricopa county

PM-10 nonattainment area. Each forecast shall identify a low, moderate or high risk of dust

generation for the next five consecutive days and shall be issued by noon on each day the

forecast is generated. At a minimum, the forecasts shall be posted on the department's

website and distributed electronically. When developing these forecasts, the department

shall consider all of the following:

(a) Projected meteorological conditions for the Maricopa county area, including all

of the following:

(i) Wind speed and direction.

(ii) Stagnation.

(iii) Recent precipitation.

(iv) Potential for precipitation.

(b) Existing concentrations of air pollution at the time of the forecast.

(c) Historic air pollution concentrations that have been observed during

meteorological conditions similar to those that are predicted to occur in the forecast. 

49-457.01. Leaf blower use restrictions and training; leaf blower equipment sellers;

informational material; outreach; applicability

A. This section applies in a county with a population of two million or more persons

or any portion of a county within an area designated by the environmental protection

3
agency as a serious PM-10 nonattainment area or a maintenance area that was designated

as a serious PM-10 nonattainment area.

B. After March 31, 2008, no person may use a leaf blower to blow landscape debris

into public roadways.

C. After March 31, 2008, no person may operate a leaf blower except on surfaces

that have been stabilized with asphaltic concrete, cement concrete, hardscape, penetration

treatment of bituminous material and seal coat of bituminous binder and a mineral

aggregate, decomposed granite cover, crushed granite cover, aggregate cover, gravel

cover, or grass or other continuous vegetative cover, or any combination of those

stabilizers.

D. At least once every three years, any person operating a leaf blower for

remuneration shall successfully complete training approved by the department on how to

operate a leaf blower in a manner designed to minimize the generation of fugitive dust

emissions. Any person who is required to be trained under this subsection shall complete

initial training no later than December 31, 2008.

E. Any person who rents or sells in the normal course of business equipment that

is used for blowing landscape debris shall provide to the buyer or renter of the equipment

printed materials that are approved by the department pursuant to this section.

F. The department shall produce printed materials and distribute those materials

to persons who sell or rent equipment used for blowing landscape debris. The printed

materials shall be designed to educate and inform the user of the equipment on the safe

and efficient use of the equipment, including methods for reducing the generation of dust,

and shall include information regarding dust control ordinances and restrictions that may

be applicable.

G. This section does not apply to any site that has a permit issued by a control

officer as defined in section 49-471 for the control of fugitive dust from dust generating

operations.

49-457.03. Off-road vehicles; pollution advisory days; applicability; penalties

A. In area A, as defined in section 49-541, a person shall not operate an

off-highway vehicle, an all-terrain vehicle or an off-road recreational motor vehicle on an

unpaved surface that is not a public or private road, street or lawful easement during any

high pollution advisory day forecast for particulate matter by the department.

B. This section does not apply to:

1. An event that is intended for off-highway vehicles, all-terrain vehicles or off-road

recreational motor vehicles and that is endorsed, authorized, permitted or sponsored by a

public agency, that occurs on a designated route or area and that includes dust abatement

measures at all staging areas, parking areas and entrances.

2. An event that occurs at a facility for which an admission or user fee is charged

and that includes dust abatement measures.

3. A closed course that is maintained with dust abatement measures.

4. An off-highway vehicle, all-terrain vehicle or off-road recreational motor vehicle

used in the normal course of business or the normal course of government operations.

5. Golf carts that are used as part of a private or public golf course operation.

C. A person who violates this section is subject to:

1. A warning for the first violation.

4
2. The imposition of a civil penalty of fifty dollars for the second violation.

3. The imposition of a civil penalty of one hundred dollars for the third violation.

4. The imposition of a civil penalty of two hundred fifty dollars for the fourth or any

subsequent violation.

D. For violations of this section, the control officer or other enforcement officer shall

use a uniform civil ticket and complaint substantially similar to a uniform traffic ticket and

complaint prescribed by the rules of procedure in civil traffic cases adopted by the supreme

court. The control officer or other enforcement officer may issue citations to persons in

violation of this section.

49-457.04. Off-highway vehicle and all-terrain vehicle dealers; informational

material; outreach; applicability

A. Any person who rents or sells in the normal course of business off-highway

vehicles, all-terrain vehicles or off-road recreational motor vehicles, other than golf carts

sold to public or private golf courses, shall provide to the buyer or renter of the vehicle

printed materials that are approved by the department pursuant to this section.

B. The department shall produce printed materials and distribute those materials

to persons who sell or rent off-highway vehicles, all-terrain vehicles or off-road recreational

motor vehicles. The printed materials shall be designed to educate and inform the user of

the vehicle on methods for reducing the generation of dust and shall include information

regarding dust control ordinances and restrictions that may be applicable. The department

shall make available on the department’s website the printed materials in a format that is

accessible to the public.

C. This section applies in a county with a population of two million or more persons

or any portion of a county in an area designated by the environmental protection agency

as a serious PM-10 nonattainment area or a maintenance area that was designated as a

serious PM-10 nonattainment area.

49-457.05. Dust action general permit; best management practices; applicability;

definitions

A. This section applies in a county with a population of two million or more persons

or any portion of a county within an area designated by the environmental protection

agency as a serious PM-10 nonattainment area or a maintenance area that was designated

as a serious PM-10 nonattainment area.

B. The director shall issue a dust action general permit for regulated activities, which

shall specify the best management practices necessary to reduce or to prevent PM-10

particulate emissions as soon as practicable before and during a day that is forecast to be

at high risk of dust generation under a forecast issued by the department pursuant to

section 49-424.

C. A person that has a permit issued by the director or a control officer for the

control of fugitive dust from dust-generating operations is not required to obtain a dust

action general permit under subsection D of this section, except that the person shall

implement the control measures required in the permit issued by the director or control

officer, including those measures related to wind, to reduce or to prevent PM-10 particulate

emissions as soon as practicable before and during a day that is forecast to be at high risk

of dust generation under a forecast issued by the department pursuant to section 49-424.

Failure to implement a control measure under this subsection shall only be enforced by the

5
director or control officer that issued the permit. The director or control officer shall not

recover penalties for violations of both this subsection and the permit based on the same

act or omission.

D. A dust action general permit may be required for any person that owns or

conducts a dust-generating operation that is found by the director to have failed to choose

and implement an applicable best management practice listed in the dust action general

permit as soon as practicable before and during a day that is forecast to be at high risk of

dust generation.

I. For the purposes of this section:

1. "Applicable implementation plan" means that term as defined in 42 United States

Code section 7602(q).

2. "Best management practices" means techniques that are verified by scientific

research and that on a case-by-case basis are practical, economically feasible and

effective in reducing PM-10 particulate emissions from a regulated activity.

3. "Control officer" has the same meaning prescribed in section 49-471.

4. "Disturbed surface area" means a portion of the earth's surface or material that

is placed on the earth's surface that has been physically moved, uncovered, destabilized

or otherwise modified from its undisturbed native condition if the potential for the emission

of fugitive dust is increased by the movement, destabilization or modification.

5. "Dust-generating operation" means disturbed surface areas, including those of

open areas or vacant lots that are not defined as agricultural land and are not used for

agricultural purposes according to sections 42-12151 and 42-12152, or any other area or

activity capable of generating fugitive dust, including the following:

(a) Land clearing, maintenance and land clean up using mechanized equipment.

(b) Earthmoving.

(c) Weed abatement by discing or blading.

(d) Excavating.

(e) Construction.

(f) Demolition.

(g) Bulk material handling, including hauling, transporting, stacking, loading and

unloading operations.

(h) Storage or transporting operations, including storage piles.

(i) Operation of outdoor equipment.

(j) Operation of motorized machinery.

(k) Establishing or using staging areas, parking areas, material storage areas or

access routes.

(l) Establishing or using unpaved haul or access roads.

(m) Installing initial landscapes using mechanized equipment.

6. "Fugitive dust" means particulate matter that could not reasonably pass through

a stack, chimney, vent or other functionally equivalent opening, that can be entrained in the

ambient air and that is caused by human or natural activities, including the movement of

soil, vehicles, equipment, blasting and wind. Fugitive dust does not include particulate

matter emitted directly from the exhaust of motor vehicles and other internal combustion

engines, from portable brazing, soldering or welding equipment or from pile drivers.

7. "Regulated activity" means all dust-generating operations except for the following:

6
(a) Normal farm cultural practices as prescribed in section 49-504, paragraph 4 or

section 49-457.

(b) Emergency activities that may disturb the soil and that are conducted by any

utility or government agency in order to prevent public injury or to restore critical utilities to

a functional status.

(c) Establishment of initial landscapes without the use of mechanized equipment,

conducting landscape maintenance without the use of mechanized equipment and playing

on or maintaining a field used for nonmotorized sports, except that these activities shall not

include grading or trenching performed to establish initial landscapes or to redesign existing

landscapes.

(d) Rooftop operations for cutting, drilling, grinding or coring roofing tile if that

activity is occurring on a pitched roof. 

49-474.01. Additional board duties in vehicle emissions control areas; definitions

A. The board of supervisors of a county which contains any portion of area A or

area B as defined in section 49-541 shall:

4. In area A, beginning January 1, 2008, develop and implement plans to stabilize

targeted unpaved roads, alleys and unpaved shoulders on targeted arterials. The plans

shall address the performance goals, the criteria for targeting the roads, alleys and

shoulders, a schedule for implementation, funding options and reporting requirements. 

Priority shall be given to the following:

(a) Unpaved roads with more than one hundred average daily trips.

(b) Unpaved shoulders on arterial roads and other road segments where vehicle

use on unpaved shoulders is evident or anticipated due to projected traffic volume.

5. In a county with a population of two million or more persons or any portion of a

county in an area designated by the environmental protection agency as a serious PM-10

nonattainment area or a maintenance area that was designated as a serious PM-10

nonattainment area, no later than March 31, 2008, adopt or amend codes or ordinances

and, no later than October 1, 2008, commence enforcement of those codes or ordinances

as necessary to require that parking, maneuvering, ingress and egress areas at

developments other than residential buildings with four or fewer units are maintained with

one or more of the following dustproof paving methods:

(a) Asphaltic concrete.

(b) Cement concrete.

(c) Penetration treatment of bituminous material and seal coat of bituminous binder

and a mineral aggregate.

(d) A stabilization method approved by the county.

6. In a county with a population of two million or more persons or any portion of a

county in an area designated by the environmental protection agency as a serious PM-10

nonattainment area or a maintenance area that was designated as a serious PM-10

nonattainment area, no later than March 31, 2008, adopt or amend codes or ordinances

and, no later than October 1, 2009, commence enforcement of those codes or ordinances

as necessary to require that parking, maneuvering, ingress and egress areas three

thousand square feet or more in size at residential buildings with four or fewer units are

maintained with a paving or stabilization method authorized by the county by code,

ordinance or permit.

7
7. In area A, no later than March 31, 2008, adopt or amend codes or ordinances as

necessary to restrict vehicle parking and use on unpaved or unstabilized vacant lots.

8. In area A, require that new or renewed contracts for street sweeping on city

streets must be conducted with street sweepers that meet the south coast air quality

management district rule 1186 street sweeper certification specifications for pick up

efficiency and PM-10 emissions in effect on January 1, 2007.

11. In a county with a population of two million or more persons or any portion of

a county within an area designated by the environmental protection agency as a serious

PM-10 nonattainment area or a maintenance area that was designated as a serious PM-10

nonattainment area, no later than March 31, 2008, adopt rule provisions, and, no later than

October 1, 2008, commence enforcement of those rule provisions regarding the

stabilization of disturbed surfaces of vacant lots that include the following:

(a) Reasonable written notice to the owner or the owner's authorized agent or the

owner's statutory agent that the unpaved disturbed surface of a vacant lot is required to be

stabilized. The notice shall be given not less than thirty days before the day set for

compliance and shall include a legal description of the property and the estimated cost to

the county for the stabilization if the owner does not comply. The notice shall be either

personally served or mailed by certified mail to the owner's statutory agent, to the owner

at the owner's last known address or to the address to which the tax bill for the property

was last mailed.

(b) Authority for the county to enter the lot to stabilize the disturbed surface at the

expense of the owner if the vacant lot has not been stabilized by the day set for

compliance.

(c) Methods for stabilization of the disturbed surface of the vacant lot, the actual

cost of stabilization and the fine that may be imposed for a violation of this section.

B. For the purposes of subsection A, paragraph 11 of this section:

1. "Disturbed surface" means a portion of the earth's surface or material placed on

the earth's surface that has been physically moved, uncovered, destabilized or otherwise

modified from its undisturbed native condition if the potential for the emission of fugitive

dust is increased by the movement, destabilization or modification.

2. Vacant lots do not include any site of disturbed surface area that is subject to a

permit issued by a control officer that requires control of PM-10 emissions from dust

generating operations.

H. Subsection A, paragraphs 5, 6 and 7 of this section do not apply to any site that

has a permit issued by a control officer as defined in section 49-471 for the control of

fugitive dust from dust generating operations.

49-474.05. Dust control; training; site coordinators

A. This section applies in a county with a population of two million or more persons

or any portion of a county in an area designated by the environmental protection agency

as a serious PM-10 nonattainment area or a maintenance area that was designated as a

serious PM-10 nonattainment area.

B. No later than January 1, 2008, the control officer shall develop and implement

basic and comprehensive training programs for the suppression of PM-10 emissions from

sources of PM-10 that are subject to a permit issued by a control officer that requires

control of PM-10 emissions from dust generating operations. The control officer may

8
approve training developed and provided by a third party and the board of supervisors may

adopt rules prescribing standards for dust control training.

C. At least once every three years, the following persons are required to

successfully complete basic dust control training:

1. The site superintendent or other designated on-site representative of the permit

holder if present at a site that has more than one acre of disturbed surface area that is

subject to a permit issued by a control officer requiring control of PM-10 emissions from

dust generating operations.

2. Water truck and water pull drivers.

D. Persons who are required to be trained under this section shall complete the

training no later than December 31, 2008. All persons who have successfully completed

training during the 2006 and 2007 calendar years are deemed to have satisfied this

requirement if the training program completed was conducted or approved by a county air

pollution control officer. Completion of the training required under subsection G satisfies

the requirements of this subsection.

E. No later than June 30, 2008, the permittee for any site of five acres or more of

disturbed surface area subject to a permit issued by a control officer requiring control of

PM-10 emissions from dust generating operations shall have on site at least one dust

control coordinator trained in accordance with this section at all times during primary dust

generating operations related to the purposes for which the dust control permit was

obtained.

F. A dust control coordinator has full authority to ensure that dust control measures

are implemented on site, including conducting inspections, deployment of dust suppression

resources and modification or shutdown of activities as needed to control dust. The dust

control coordinator shall be responsible for managing dust prevention and dust control on

the site.

G. At least once every three years, the dust control coordinator shall successfully

complete a comprehensive dust control class conducted or approved under subsection A

by the county air pollution control officer with jurisdiction over the site. The dust control

coordinator shall have a valid dust training certification identification card readily accessible

on site while acting as a dust control coordinator. All persons having successfully

completed training during the 2006 and 2007 calendar years are deemed to have satisfied

this requirement if the training program completed was conducted or approved by a county

air pollution control officer.

H. Subsections C and D do not apply when on-site dust generating operations are

conducted by a permittee who is required to obtain a single permit for multiple

noncontiguous sites that is issued by a control officer and that requires control of PM-10

emissions.

I. The requirements of subsections E and F lapse if all of the following apply:

1. The area of the disturbed surface area is less than five acres.

2. The previously disturbed areas are stabilized in accordance with the

requirements of applicable rules.

3. The permittee provides notice of the acreage stabilized to the control officer.

J. Permittees who are required to obtain a single permit for multiple noncontiguous

sites that is issued by a control officer and that requires control of PM-10 emissions from

9
dust generating operations shall have on sites with greater than one acre of disturbed

surface area at least one individual who is designated by the permittee as a dust control

coordinator trained in accordance with subsection C. The dust control coordinator shall be

present on site at all times during primary dust generating activities that are related to the

purposes for which the permit was obtained. This subsection does not apply to permittees

subject to subsections B and C.

49-474.06. Dust control; subcontractor registration; fee

A. In an area designated by the environmental protection agency as a serious

PM-10 nonattainment area or a maintenance area that was designated as a serious PM-10

nonattainment area, a subcontractor who is engaged in dust generating operations at a site

that is subject to a permit that is issued by a control officer and that requires control of

PM-10 emissions from dust generating operations shall register with the control officer by

submitting information in the manner prescribed by the control officer. The control officer

shall issue a registration number after payment of the fee authorized under subsection C.

B. The subcontractor shall have its registration number readily accessible on site

while conducting any dust generating operations.

C. The control officer may establish and assess a fee for the registration required

under subsection a based on the total cost of processing the registration and issuance of

a registration number.

49-501. Unlawful open burning; exceptions; fine; definition

A. Notwithstanding the provisions of any other section of this article:

2. From May 1 through September 30 each year, it is unlawful for any person to

ignite, cause to be ignited, permit to be ignited or suffer, allow or maintain any open outdoor

fire in area A as defined in section 49-541.

B. The following fires are excepted from this section:

1. Fires used only for cooking of food or for providing warmth for human beings or

the branding of animals or the use of orchard heaters for the purpose of frost protection in

farming or nursery operations.

C. Permission for the setting of any fire given by a public officer in the performance

of official duty under sebsection B, paragraph 2, 3 or 4 of this section shall be given in

writing and a copy of the written permission shall be transmitted directly to the director of

environmental quality and the control officer of the county, district or region in which such

fire is allowed. The setting of any such fire shall be conducted in a manner and at such

time as approved by the control officer or the director of environmental quality, unless doing

so would defeat the purpose of the exemption.

F. Nothing in this section is intended to permit any practice which is a violation of

any statute, ordinance, rule or regulation in a county with a population in excess of one

million two hundred thousand persons. Notwithstanding any other law, such a county shall

prohibit by ordinance the use of wood burning chimineas, outdoor fire pits and similar

outdoor fires on those days for which the county has issued a no burn day restriction.

G. A person who violates any provision of this section may be served a notice of

violation and be subject to the enforcement provisions of this article to the same extent as

a person violating any rule or regulation adopted pursuant to this article, except that a

violation that lasts no more than twenty-four hours and that is the first violation committed

by that person is subject to a civil penalty of no more than five hundred dollars.

10
49-541. Definitions

In this article, unless the context otherwise requires:

1. "Area A" means the area delineated as follows:

(a) In Maricopa county:

Township 8 north, range 2 east and range 3 east

Township 7 north, range 2 west through range 5 east

Township 6 north, range 5 west through range 6 east

Township 5 north, range 5 west through range 7 east

Township 4 north, range 5 west through range 8 east

Township 3 north, range 5 west through range 8 east

Township 2 north, range 5 west through range 8 east

Township 1 north, range 5 west through range 7 east

Township 1 south, range 5 west through range 7 east

Township 2 south, range 5 west through range 7 east

Township 3 south, range 5 west through range 1 east

Township 4 south, range 5 west through range 1 east

(b) In Pinal county:

Township 1 north, range 8 east and range 9 east

Township 1 south, range 8 east and range 9 east

Township 2 south, range 8 east and range 9 east

Township 3 south, range 7 east through range 9 east

(c) In Yavapai county:

Township 7 north, range 1 east and range 1 west through range 2 west

Township 6 north, range 1 east and range 1 west

11
APPENDIX C

EXHIBIT 2:

Maricopa County Resolution to Evaluate Measures in

the MAG 2012 Five Percent Plan for PM-10 for the

Maricopa County Nonattainment Area



APPENDIX C

EXHIBIT 3:

Arizona Department of Environmental Quality Dust

Action General Permit
 ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY 

Air Quality Division 

1110 West Washington Street  Phoenix, AZ 85007  Phone: (602) 771-2308 

DUST ACTION GENERAL PERMIT 

(As required by Arizona Revised Statutes, Title 49, Chapter 3, Article 2, Section 49-457.05)

This air quality control permit does not relieve applicant of responsibility for 

meeting all air pollution regulations

THIS GENERAL PERMIT ISSUED SUBJECT TO THE FOLLOWING Conditions contained in Attachments

“A”, “B” and “C” 

ADEQ GENERAL PERMIT NUMBER NA EXPIRATION DATE December 30, 2016

PERMIT ISSUED THIS 30th DAY OF December , 2011 

 

 Eric C. Massey, Director, Air Quality Division

SIGNATURE TITLE 
Dust Action General Permit 2 of 18 December 30, 2011 

This page left blank intentionally 
Dust Action General Permit 3 of 18 December 30, 2011 

DUST ACTION GENERAL PERMIT 

TABLE OF CONTENTS 

INTRODUCTION ............................................................................................................................................................................ 4

ATTACHMENT "A": GENERAL PROVISIONS...................................................................................................................... 5 

I. APPLICABILITY............................................................................................................................................................. 5 

II. DEFINTIONS................................................................................................................................................................... 5 

III. GENERAL PERMIT EXPIRATION AND RENEWAL.................................................................................................. 7 

IV. COMPLIANCE WITH PERMIT CONDITIONS............................................................................................................. 7 

V. ISSUANCE OF A DUST ACTION GENERAL PERMIT REQUIREMENT TO OPERATE FOR CAUSE .................. 7 

VI. COMPLIANCE CERTIFICATION.................................................................................................................................. 9 

VII. INSPECTION AND ENTRY ......................................................................................................................................... 10 

VIII. RECORD KEEPING REQUIREMENTS....................................................................................................................... 10 

IX. REPORTING REQUIREMENTS................................................................................................................................... 10 

X. DUTY TO PROVIDE INFORMATION ........................................................................................................................ 10 

XI. PROPERTY RIGHTS..................................................................................................................................................... 11 

XII. SEVERABILITY CLAUSE............................................................................................................................................ 11 

XIII TERMINATION FOR CAUSE ...................................................................................................................................... 11 

XIV. RENTING OR LEASING A REGULATED ACTIVITY .............................................................................................. 11 

ATTACHMENT "B": SPECIFIC CONDITIONS .................................................................................................................... 12 

I. GENERAL CONDITIONS............................................................................................................................................. 12 

II. BEST MANAGEMENT PRACTICES REQUIREMENT ............................................................................................. 12 

III. ALTERNATIVE BEST MANAGEMENT PRACTICES NOT INCLUDED IN THE GENERAL PERMIT ............... 12 

ATTACHMENT “C”: BEST MANAGEMENT PRACTICE EXAMPLES............................................................................ 14

I. VEHICLE USE IN OPEN AREAS AND VACANT LOTS........................................................................................... 14 

II. OPEN AREAS AND VACANT LOTS .......................................................................................................................... 14 

III. UNPAVED PARKING LOTS........................................................................................................................................ 14 

IV. UNPAVED ROADWAYS, ALLEYWAYS AND ROAD SHOULDERS..................................................................... 15 

V. LIVESTOCK SPECIAL EVENTS NOT OTHERWISE COVERED UNDER A.R.S. §. 49-457 .................................. 15 

VI. EASEMENTS, RIGHTS OF WAY, AND ACCESS ROADS FOR UTILITIES ........................................................... 16 

VII. TRACKOUT FROM UNPERMITTED SOURCES....................................................................................................... 16 

VIII. MANAGED OFF HIGH WAY VEHICLE ROUTES .................................................................................................... 16 
Dust Action General Permit 4 of 18 December 30, 2011 

DUST ACTION GENERAL PERMIT 

INTRODUCTION 

Since the start of Calendar Year 2008, the majority of exceedances of the PM10 National Ambient Air 

Quality Standard (NAAQS) in the Maricopa County serious PM10 nonattainment area have been related to 

high wind events. High wind events, along with a number of other meteorological conditions that can 

lead to the generation of dust can be predicted through meteorological forecasts. 

In accordance with A.R.S. § 49-424(11), ADEQ is developing and disseminating an air quality dust 

forecast for the Maricopa County serious PM10 nonattainment area. Based upon knowledge of historical 

and recent meteorological conditions, and the prediction of such factors as wind speed and wind direction, 

forecasts identify the potential risk of dust entrainment as “Low”, “Moderate” or “High” for the next five 

consecutive days. ADEQ updates this five-day Maricopa County Dust Control Forecast every Sunday 

through Friday, and posts it on its website at http://www.azdeq.gov/environ/air/ozone/mcdust.pdf. 

In accordance with A.R.S. § 49-457.05, this Dust Action General Permit identifies a series of Best 

Management Practices (BMPs) for specific dust generating operations. When ADEQ’s Maricopa County 

Dust Control Forecast predicts that a day is at high risk for dust generation, those dust generating 

operations that are not already required to control dust through a permit issued by the Arizona Department 

of Environmental Quality (ADEQ) or the Maricopa County Air Quality Department (MCAQD) are 

expected to choose and implement at least one BMP to reduce or prevent PM10 emissions. 

Implementation of a BMP is expected to occur as soon as practicable before and during the high risk 

event. Although the BMPs in the Dust Action General Permit only apply to those sources that do not 

already have a permit, dust generating operations with an air quality permit are also expected to 

implement the dust controls in their permit at the same time. 

According to statute, BMPs identified in the Dust Action General Permit are expected to be employed 

absent the requirement to obtain an air quality permit. If the owner or operator of a dust-generating 

operation is found by ADEQ’s Director to have failed to choose and implement an applicable BMP as 

soon as practicable before and during a day that is forecast to be at high risk of dust generation, then the 

owner or operator can be required to obtain a Requirement to Operate (RTO) under the Dust Action 

General Permit. The process by which ADEQ’s Director makes such a finding is identified within the 

Dust Action General Permit. Violations of the Dust Action General Permit are subject to the enforcement 

requirements of Arizona Revised Statutes Title 49, Chapter 3, Article 2, including civil penalties of up to 

ten thousand dollars per day, per violation, pursuant to Section 463. 

In accordance with A.R.S. § 49-457.05(E) this Dust Action General Permit is subject to a 30-day public 

comment period and shall be effective for a period of five-years. 
Dust Action General Permit 5 of 18 December 30, 2011 

DUST ACTION GENERAL PERMIT 

ATTACHMENT “A”: GENERAL PROVISIONS 

I. APPLICABILITY 

A. This Dust Action General Permit is applicable to the owner or operator of a regulated 

activity within a county with a population of two million or more persons, or any portion 

of a county within areas designated by the environmental protection agency as a serious 

PM10 nonattainment area or a maintenance area that was previously designated as a 

serious PM10 nonattainment area who is required by the Director to obtain a general 

permit in accordance with Condition IV of this Attachment. 

B. Each owner or operator of a regulated activity that is required by the Director to obtain 

this Dust Action General Permit shall obtain a Requirement to Operate that includes the 

following information: 

 1. The regulated activity; 

 2. The legal owner or operator of the regulated activity; and 

3. The physical address, location, or parcel number where the regulated activity 

occurs. 

C. Each Requirement to Operate (RTO) issued under this general permit shall only apply to 

those regulated activities that are identified pursuant to Section V of this attachment and 

in the RTO, are under the control of the same Permittee, and are located on one or more 

properties that are adjacent or contiguous to the location of the regulated activity. 

II. DEFINITIONS 

For the purposes of the Dust Action General Permit the following terms are defined as follows: 

A. "Applicable implementation plan" means that term as defined in 42 United States Code 

section 7602(q). 

B. "Best management practices" means techniques that are verified by scientific research 

and that on a case-by-case basis are practical, economically feasible and effective in 

reducing PM10 particulate emissions from a regulated activity. 

C. "Control officer" has the same meaning prescribed in Arizona Revised Statutes § 49-471. 

D. “Designated, managed or open trail system” means roads, highways, multiple use 

corridors, trails or routes that are part of a system of trails and routes that are designated, 

managed or opened to public motor vehicle travel by government land management 

agency by rule, order, travel management plan, sign, or map approved by such agency. 

E. "Disturbed surface area" means a portion of the earth's surface or material that is placed 

on the earth's surface that has been physically moved, uncovered, destabilized or 

otherwise modified from its undisturbed native condition if the potential for the emission 

of fugitive dust is increased by the movement, destabilization or modification. 

F. "Dust-generating operation" means disturbed surface areas, including those of open areas 
Dust Action General Permit 6 of 18 December 30, 2011 

or vacant lots that are not defined as agricultural land and are not used for agricultural 

purposes according to Arizona Revised Statutes §§ 42-12151 and 42-12152, or any other 

area or activity capable of generating fugitive dust, including the following: 

1. Land clearing, maintenance and land clean-up using mechanized equipment. 

2. Earthmoving. 

3. Weed abatement by discing or blading. 

4. Excavating. 

5. Construction. 

6. Demolition. 

7. Bulk material handling, including hauling, transporting, stacking, loading and 

unloading operations. 

8. Storage or transporting operations, including storage piles. 

9. Operation of outdoor equipment. 

10. Operation of motorized machinery. 

11. Establishing or using staging areas, parking areas, material storage areas or 

access routes. 

12. Establishing or using unpaved haul or access roads. 

13. Installing initial landscapes using mechanized equipment. 

G. “Dust Suppressant” means water, hygroscopic material, a solution of water and chemical 

surfactant, foam, non-toxic chemical stabilizer, or any other dust palliative, which is not 

prohibited for ground surface application by the Environmental Protection Agency (EPA) 

or the Arizona Department of Environmental Quality (ADEQ), or any applicable law, 

rule, or regulation, as a treatment material for reducing fugitive dust emissions. 

H. "Fugitive dust" means particulate matter that could not reasonably pass through a stack, 

chimney, vent or other functionally equivalent opening, that can be entrained in the 

ambient air and that is caused by human or natural activities, including the movement of 

soil, vehicles, equipment, blasting and wind. Fugitive dust does not include particulate 

matter emitted directly from the exhaust of motor vehicles and other internal combustion 

engines, from portable brazing, soldering or welding equipment or from pile drivers. 

I. “Livestock special event” means displaying, racing, training or exercising livestock 

during an event at which a fee is collected, or is open to 24 or more persons including 

staff, participants and spectators, and is conducted at a facility specifically designed for 

this purpose and is not already subject to A.R.S. § 49-457.”

J. “Owner or operator” means any person who owns, leases, operates, controls, or 

supervises a regulated activity subject to the requirements of this general permit. 
Dust Action General Permit 7 of 18 December 30, 2011 

K. "Regulated activity" means all dust-generating operations except for the following: 

1. Normal farm cultural practices as prescribed in A.R.S. §§ 49-504(4) or 49-457. 

2. Emergency activities that may disturb the soil and that are conducted by any 

utility or government agency in order to prevent public injury or to restore 

critical utilities to a functional status. 

3. Establishment of initial landscapes without the use of mechanized equipment, 

conducting landscape maintenance without the use of mechanized equipment and 

playing on or maintaining a field used for nonmotorized sports, except that these 

activities shall not include grading or trenching performed to establish initial 

landscapes or to redesign existing landscapes. 

4. Rooftop operations for cutting, drilling, grinding or coring roofing tile if that 

activity is occurring on a pitched roof. 

III. GENERAL PERMIT EXPIRATION, RENEWAL AND RE-OPENING 

A. This Dust Action General Permit is valid for a period of five years from the date of 

issuance. The Director of ADEQ (Director) shall review and may renew this General 

Permit every five years from its date of issuance. The Permittee’s RTOs shall coincide 

with the term of this General Permit, regardless of when the RTO was issued during this 

five year period. The Director may require an existing RTO to be renewed at the time 

that this General Permit is renewed. 

B. The Director may periodically reexamine, evaluate and modify the Dust Action General 

Permit as prescribed in A.R.S. Section 49-426(H)(2) through (6). After approval by the 

Director, any modifications to the Dust Action General Permit shall be provided to the 

Control Officer and shall be submitted to the United States Environmental Protection 

Agency as a revision to the applicable State Implementation Plan. 

C. At the time that the public notice is required, pursuant to issuance of the proposed 

General Permit renewal, the Director shall notify in writing all Permittees with existing 

RTOs that have been renewed. The written notice shall describe the source’s duty to 

comply with the conditions of the General Permit. 

IV. COMPLIANCE WITH PERMIT CONDITIONS 

A. The Permittee shall comply with all Conditions of this General Permit including all 

applicable requirements of Arizona air quality statutes and the air quality rules. Any 

permit noncompliance constitutes a violation of the Arizona Revised Statutes and is 

grounds for enforcement action, including, but not limited to civil penalties. In addition, 

non-compliance with any federally enforceable requirements constitutes a violation of the 

Clean Air Act. 

B. It shall not be a defense for a Permittee in an enforcement action that it would have been 

necessary to halt or reduce the permitted activity in order to maintain compliance with the 

conditions of this General Permit. 

V. ISSUANCE OF A DUST ACTION GENERAL PERMIT FOR CAUSE 

A. The Director may require the owner or operator of a regulated activity to obtain a 
Dust Action General Permit 8 of 18 December 30, 2011 

Requirement to Operate under the Dust Action General Permit at any time if it can be 

demonstrated that: 

1. The regulated activity is not otherwise subject to an air quality permit issued by 

the Director or the Maricopa County Air Quality Department Control Officer; 

and 

2. The owner or operator of a regulated activity did not choose or implement a Best 

Management Practice as soon as practicable before and during a day forecast to 

be at high risk of dust generation. 

B. A demonstration that the owner or operator of a regulated activity did not choose or 

implement a Best Management Practice shall include the following: 

1. Documentation that includes a description of the regulated activity; 

2. Documentation that clearly identifies the legal owner or operator of the regulated 

activity; 

3. Documentation that clearly identifies the physical address(es), location(s), or 

parcel number(s) where the regulated activity occurred; 

4. Documentation that includes records, field reports or photographic evidence that 

demonstrates that the owner or operator of the regulated activity was not 

implementing a Best Management Practice as soon as practicable before and 

during a day forecast to be at high risk of dust generation; 

5. A description of the actions taken by the owner or operator of the regulated 

activity to comply with the required Best Management Practice(s) at the time of 

the inspection; 

6. Documentation that identifies any previous inspections associated with the 

owner, operator, physical address(es), location(s), or parcel number(s) as well as 

results of those inspections; and 

7. Documentation that demonstrates that the owner or operator of the regulated 

activity has been provided with a copy of the documentation identified in 

Condition III.B.1 through 6 above. 

C. Upon receipt of a demonstration that the owner or operator of a regulated activity did not 

choose or implement a Best Management Practice, the Director shall: 

1. Notify the owner or operator of the receipt of the demonstration; and 

2. Provide the owner or operator with five (5) business days to demonstrate that a 

Best Management Practice was employed at the time of the inspection; or 

provide a document that identifies the Best Management Practice(s) that will be 

employed at the address(es), location(s), or parcel number(s) identified in the 

Director’s letter. 

D. If the Director determines that the owner or operator of a regulated activity was not in 

compliance with the required Best Management Practices as soon as practicable before 

and during a day forecast to be at high risk of dust generation, and has not adequately 
Dust Action General Permit 9 of 18 December 30, 2011 

identified the Best Management Practices that will be employed as soon as practicable 

before and during future days forecast to be at high risk of dust generation the Director 

shall issue a RTO under the Dust Action General Permit and shall require the owner or 

operator to choose and implement Best Management Practices within five (5) business 

days of the determination. 

VI. TERMINATION FOR CAUSE 

A. The Permittee may apply to the Director for termination of a RTO under the general 

permit if it can be demonstrated that: 

1. The regulated activity is subject to an air quality permit issued by the Director or 

the Maricopa County Air Quality Department Control Officer; 

2. The Permittee is no longer the legal owner or operator of the regulated activity by 

demonstrating one of the following; 

a. The regulated activity has been sold, transferred or otherwise been 

dispossessed by the Permittee; or 

b. The regulated activity is no longer capable of being operated at the 

physical address(es), location(s), or parcel number(s) where the regulated 

activity occurred; or 

3. The Permittee provides documentation that a Best Management Practice has been 

chosen and implemented for each applicable regulated activity as soon as 

practicable before and during a day forecast to be at high risk of dust generation 

by submitting one of the following: 

a. Demonstrating that a Best Management Practice of a permanent nature 

has been applied to the regulated activity; 

b. Submitting a copy of the records required in Attachment “B” Conditions 

I.D and II.C for the two most recent consecutive years after the time that 

the Dust Action General Permit has been issued; or 

c. Submitting a copy of the records required in Attachment “B” Conditions 

I.D and II.C for a different time period than that prescribed in Condition 

VI.A.3.b above based upon a demonstration that: 

(1) A regulated activity was not owned or operated at the location 

during the two most recent consecutive years; or 

(2) There were no days forecast to be at high risk of dust generation 

during the two most recent consecutive years. 

B. The Director may terminate a RTO under the general permit if the Director makes an 

independent finding that:

1. The regulated activity is subject to an air quality permit issued by the Director or 

the Maricopa County Air Quality Department Control Officer; 

2. In accordance with Condition VI.A.2 above, the Permittee is no longer the legal 
Dust Action General Permit 10 of 18 December 30, 2011 

owner or operator of the regulated activity. 

VII. COMPLIANCE CERTIFICATION 

A. The Permittee shall submit to the Director a compliance certification once each year, 

which describes the compliance status of the source with respect to each General Permit 

condition and the methods used for determining the compliance status. This certification 

shall be submitted by January 31st and shall cover the previous calendar year. 

The compliance certification shall include the following: 

1. Identification of the dust-generating operation owner or operated by the 

Permittee. 

2. Identification of the Best Management Practice(s) used by the Permittee to 

comply with the terms and conditions of this General Permit. 

B. The Director may request additional information to support the compliance certification.

VIII. INSPECTION AND ENTRY

Upon presentation of credentials and other documents as may be required by law, the Permittee 

shall allow the Department, or an authorized representative (including an authorized contractor 

acting as a representative of the Department), to perform the following: 

A. Enter upon the Permittee’s premises where a regulated activity is located or conducted, or 

where records must be kept under the conditions of this General Permit; 

B. Have access to and copy, at reasonable times, any records that are required to be kept 

under the conditions of this General Permit; 

C. Inspect, at reasonable times, any facilities, equipment (including monitoring and air 

pollution control equipment), practices, or operations regulated or required under this 

General Permit; 

D. Sample or monitor at reasonable times, substances or parameters for the purpose of 

assuring compliance with the General Permit or other applicable requirements; and 

E. Record any inspection by use of written, electronic, magnetic and photographic media. 

IX. RECORD KEEPING REQUIREMENTS 

Until the RTO under the general permit is terminated pursuant to Section XIII of Attachment 

“A”, the Permittee shall retain records of all required records and supporting information and 

shall make the records available to the Director upon request. 

X. REPORTING REQUIREMENTS

The Permittee shall submit the following reports: 

A. Compliance certifications in accordance with Section IV of Attachment “A”. 

B. Other reports required by any condition in Attachment “B”.
Dust Action General Permit 11 of 18 December 30, 2011 

XI. DUTY TO PROVIDE INFORMATION 

A. The Permittee shall furnish to the Director, within a reasonable time, any information that 

the Director may request in writing to determine whether cause exists for revoking the 

General Permit coverage, or to determine compliance with this General Permit. Upon 

request, the Permittee shall also furnish to the Director copies of records that the 

Permittee is required to keep under the General Permit. For information claimed 

confidential, the Permittee shall furnish an additional copy of such records directly to the 

Director along with a claim of confidentiality. 

B. If the Permittee has failed to submit any relevant facts or if the Permittee has submitted 

incorrect information in a General Permit coverage application, the Permittee shall, upon 

becoming aware of such failure or incorrect submittal, promptly submit such 

supplementary facts or corrected information. 

XII. PROPERTY RIGHTS

This General Permit does not convey any property rights of any sort, or any exclusive privilege. 

XIII. SEVERABILITY CLAUSE 

The provisions of this General Permit are severable. In the event of a challenge to any portion of 

this General Permit, or if any portion of this permit is held invalid, the remaining permit 

conditions remain valid and in force. 

XIV. RENTING OR LEASING A REGULATED ACTIVITY 

In the case that a regulated activity covered under this general permit is rented or leased, a copy 

of this General Permit and relevant RTOs shall be provided by the owner to the renter or lessee, 

and the renter or lessee shall be bound by this permit's provisions. In the event a copy of this 

General Permit and relevant RTOs are not provided to the renter or lessee, both the owner and the 

renter or lessee shall be responsible for the implementation of a Best Management Practice in 

compliance with the General Permit conditions and any violations thereof. 
Dust Action General Permit 12 of 18 December 30, 2011 

DUST ACTION GENERAL PERMIT 

ATTACHMENT “B”: SPECIFIC CONDITIONS 

I. GENERAL CONDITIONS 

A. The Permittee shall obtain a copy of the Maricopa County Dust Control Forecast each 

day that it is updated by: 

1. Accessing the forecast through ADEQ’s website at: 

http://www.azdeq.gov/environ/air/ozone/mcdust.pdf; or 

2. Signing up for ADEQ’s electronic mailing system. 

B. The Permittee shall register to receive all available electronic updates from all Maricopa 

County Air Quality Department air quality monitors within 4 miles of the regulated 

activity. 

C. The Permittee shall notify employees who conduct or operate a regulated activity when 

the Maricopa County Dust Control Forecast identifies the following day as being at high 

risk of dust generation. 

D. The Permittee shall keep a record of each Maricopa County Dust Action Control 

Forecast that identifies the next calendar day as being at high risk of dust generation and 

a log of the date, time and method used to notify employees. 

II. BEST MANAGEMENT PRACTICES REQUIREMENT 

A. As soon as practicable before, and during a day identified by the Maricopa County Dust 

Control Forecast as being at high risk of dust generation, the Permittee shall take 

reasonable precautions to reduce or prevent particulate matter from becoming airborne. 

Examples of Best Management Practices for specific source categories are included in 

Attachment “C” of this permit. 

B. The Permittee shall choose and implement a Best Management Practice for each 

regulated activity owned or operated by the Permittee. 

C. The Permittee shall keep records of the Best Management Practices that are employed in 

advance of and during a day identified by the Maricopa County Dust Control Forecast as 

being at high risk of dust generation. 

III. ALTERNATIVE BEST MANAGEMENT PRACTICES NOT INCLUDED IN THE 

GENERAL PERMIT

A. The Permittee may choose and implement an alternative Best Management Practice that 

is not included in Attachment “C” of this permit provided that the Permittee maintains 

records of documentation demonstrating that the alternative Best Management Practice 

that was selected and implemented achieves an equivalent or greater control of PM10

particle emissions than an example included in Attachment “C”; 

B. Any person may petition the Director to make a determination that an alternative Best 
Dust Action General Permit 13 of 18 December 30, 2011 

Management Practice achieves an equivalent or greater control of PM10 emissions than 

the examples included in Attachment “C”. These petitions shall include the following: 

1. A description of the alternative Best Management Practice; and 

2. A demonstration that the alternative Best Management Practice achieves an 

equivalent or greater control of PM10 emissions than an example included in 

Attachment “C”. 

C. Upon renewal or re-opening of this general permit, the Director shall add to the Best 

Management Practices examples in Attachment “C” any alternative Best Management 

Practices that were approved under Condition III.B above.
Dust Action General Permit 14 of 18 December 30, 2011 

DUST ACTION GENERAL PERMIT 

ATTACHMENT “C”: BEST MANAGEMENT PRACTICE EXAMPLES 

I. VEHICLE USE IN OPEN AREAS AND VACANT LOTS 

 

A. This condition does not apply to designated, managed or opened trail systems. 

B. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall: 

1. Reduce or prevent motor vehicle access to the open area or vacant lots by: 

a. Installing barriers, curbs, fences, gates, posts, shrubs, trees or other 

effective control measures; or 

b. Installing no trespassing, no parking or no access signs that comply with 

local, County, State or Federal sign standards; or 

2. Uniformly apply and maintain surface gravel or chemical or organic stabilizers to 

all areas disturbed by motor vehicles. 

C. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain and repair as necessary the best 

management practice selected in Condition I.B. above. 

II. OPEN AREAS AND VACANT LOTS 

A. This condition does not apply to designated, managed or opened trail systems. 

B. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall control PM10 emissions from open areas and vacant lots 

by: 

1. Establishing vegetative ground cover on all disturbed surface area; or 

2. Increasing the use of dust suppressants on the open area or vacant lot; or 

3. Uniformly applying and maintaining surface gravel or chemical or organic 

stabilizers to all disturbed areas. 

C. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Condition II.B above. 

III. UNPAVED PARKING LOTS 

A. This condition does not apply to designated, managed or opened trail systems. 

B. This condition applies to parking, maneuvering, ingress and egress areas at developments 

other than residential buildings with four or fewer units. 
Dust Action General Permit 15 of 18 December 30, 2011 

C. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall control PM10 emissions from unpaved parking lots by: 

1. Increasing the use of dust suppressants other than water on the unpaved parking 

lot; or 

2. Uniformly applying and maintaining surface gravel or chemical or organic 

stabilizers to all disturbed areas. 

D. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Condition III.C above. 

IV. UNPAVED ROADWAYS, ALLEYWAYS AND ROAD SHOULDERS 

A. This condition does not apply to designated, managed or opened trail systems. 

B. This condition applies to unpaved roadways or alleyways that experience an average of 

150 vehicle trips or more per day. 

C. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall control PM10 emissions by: 

1. Reducing or preventing motor vehicle access as prescribed in Condition I.B 

above; 

2. Increasing the use of dust suppressants other than water on the unpaved roadway 

or alleyway; or 

3. Uniformly applying and maintaining surface gravel or chemical or organic 

stabilizers to the unpaved roadway or alleyway. 

D. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Condition IV.C above. 

V. LIVESTOCK SPECIAL EVENTS NOT COVERED UNDER A.R.S. § 49-457 

A. This condition applies to livestock facilities at which special events that are not already 

covered under A.R.S. § 49-457 occur.

B. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall control PM10 emissions by: 

1. Increasing the use of dust suppressants, including water, on unpaved access 

connections and feed lane access areas at the livestock special event; or 

2. Uniformly applying and maintaining surface gravel or chemical or organic 

stabilizers to all areas disturbed by motor vehicles other than areas where such 

application will create a documentable hazard for livestock activities; or. 
Dust Action General Permit 16 of 18 December 30, 2011 

3. Reducing or preventing motor vehicle access on unpaved access connections and 

feed lane access areas at the livestock special event by: 

a. Installing barriers, curbs, fences, gates, posts, shrubs, trees or other 

effective control measures; or 

b. Installing no trespassing, no parking or no access signs that comply with 

local, County, State or Federal sign standards; or 

C. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Condition V.B above. 

VI. EASEMENTS, RIGHTS-OF-WAY, AND ACCESS ROADS FOR UTILITIES 

A. This condition does not apply to designated, managed or opened trail systems. 

B. This condition applies to easements, rights-of-way, and access roads for utilities 

(transmission of electricity, natural gas, oil, water, and gas) that experience an average of 

150 vehicle trips or more per day. 

C. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall control PM10 emissions by: 

1. Reducing or preventing motor vehicle access as prescribed in Condition I.B 

above; 

2. Increasing the use of dust suppressants other than water on the easement, rightof-way or access road; or 

3. Uniformly applying and maintaining surface gravel or chemical or organic 

stabilizers to the easement, right-of-way or access road. 

D. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Condition VI.C above. 

VII. TRACKOUT OR DEPOSITS OF BULK MATERIAL 

As soon as practicable before and during a day forecast to be at high risk of dust generation, the 

Permittee shall clean-up loose material or remove deposits of bulk material from areas accessible 

to the public on day before and during high risk day.

VIII. DESIGNATED, MANAGED OR OPENED TRAIL SYSTEMS

A. During the course of each calendar year, the Permittee shall control PM10

emissions from designated, managed or opened trail systems by employing 

adaptive management techniques such as: 

1. Posting public information to educate the riding public about at the 

impacts of air quality regulation on the use of off-highway vehicles, 
Dust Action General Permit 17 of 18 December 30, 2011 

including the restriction of operation during high pollution advisories, 

through methods similar to kiosks, distribution of material at major events 

and dealerships, and other Public Service Announcements; and 

2. Conducting mechanized trail repair and maintenance at slow speeds that: 

a. Reduce the speed of water run-off on the designated, managed or 

opened trail system; 

b. Reduce the amount of silt that would otherwise accumulate on the 

designated, managed or open trail system; 

c. Add grade dip or water controls to the designated, managed or 

open trail system; or 

d. Add or repair silt traps on water drains; or 

3. Re-routing an existing designated, managed or opened trail that causes 

traffic to avoid soils susceptible to dust generation; or constructing a new 

designated, managed or opened trails that allow for appropriate trail repair 

and maintenance and include speed limiting features such as turns and 

climbs; or 

4. Rehabilitating open parking areas, mine sites, and old unpaved roads that 

are not designated, managed or opened trail systems. Rehabilitation 

includes re-contouring the areas, replanting trees and spreading native 

seed to hold soil together and reduce windblown dust; or 

B. As soon as practicable before and during a day forecast to be at high risk of dust 

generation, the Permittee shall control PM10 emissions from disturbed areas along 

the designated, managed or opened trail system by employing adaptive 

management techniques such as: 

1. Applying a proven dust surfactant; 

2. Repairing roads and other unpaved surfaces to control the water run-off 

and silt; 

3. Using soil binders and compaction to allow for light to moderate traffic 

flow; or 

4. Installing an engineered road or surface that: 

a. Raises the road or surface bed above grade; 

b. Uses an ABC road mix and binder; 

c. Compacts the road or surface; and 

d. Crowns to drain water; or 

C. As soon as practicable before and during the day forecast to be at high risk of dust 

generation the Permittee shall inspect, maintain, and repair, as necessary, the best 

management practice selected in Conditions VI.A or B above; or 
Dust Action General Permit 18 of 18 December 30, 2011 

D. When the Maricopa County Dust Control Forecast identifies the following day as being 

at high risk of dust the Permittee shall post information at kiosks or use equivalent 

methods to notify users of designated, managed or opened trail system.
APPENDIX C

EXHIBIT 4:

Arizona Department of Environmental Quality

Commitment to Revise the MAG 2012 Five Percent

Plan for PM-10 for the Maricopa County Nonattainment

Area if Necessary for the Emerging and Voluntary

Measure


APPENDIX D
APPENDIX D

EXHIBIT 1:

Agricultural Best Management Practices Program
AGRICULTURAL BEST MANAGEMENT PRACTICES PROGRAM

Throughout the course of the development of the MAG 2012 Five Percent Plan for PM-10 for

the Maricopa Nonattainment Area (Five Percent Plan) the Governor’s Agricultural Best

Management Practices (BMP) Committee has worked to enhance its Best Management Practices

program. On December 9, 2011, the Ag BMP Committee approved enhancements to the BMP

program. On behalf of the Governor’s Agricultural BMP Committee, the Arizona Department of

Environmental Quality (ADEQ) sent a Notice of Exempt Rule Making to the Secretary of State’s

Office on December 29, 2011, making the enhanced BMP program effective on that same date. 

The enhanced BMP program is enforceable as a matter of State law. ADEQ has determined that

implementation of the program will result in a numerically quantifiable air quality benefit

throughout the Maricopa nonattainment area. ADEQ has also determined that the program will

result in reduced concentrations of PM-10 at the monitors throughout the same area. 

The program will also have benefits outside of Maricopa County. According to the 2011 rule

enhancements, the Agricultural BMP program automatically becomes effective in any area of the

State that is designated as nonattainment for the PM-10 National Ambient Air Quality Standard

(NAAQS) after June 1, 2009. For areas designated as moderate nonattainment, one BMP must

be employed, whereas in areas that are designated as serious nonattainment, two BMPs must be

employed.

ADEQ has determined that the revised Five Percent Plan already meets EPA’s requirements for

annual five percent reductions in PM-10 emissions and a demonstration that the plan will result

in the area’s attainment with the 24-hour PM-10 NAAQS without the inclusion of the enhanced

Agricultural BMP program. As part of the public comment period, ADEQ requested comments

about whether the Department should make a commitment to EPA to include the enhanced

Agricultural BMP program as part of the Five Percent Plan or, given its statewide benefits, if the

Department should include the enhanced Agricultural BMP program as a stand alone revision to

the State Implementation Plan.

No public comments were made in response to ADEQ’s request. Based on the facts listed

above, and because the program is now implementable on a statewide basis, ADEQ has

determined that it will submit the program as a separate, independent revision to the State

Implementation Plan.

Prepared by the Arizona Department of Environmental Quality.
APPENDIX E
APPENDIX E

EXHIBIT 1:

Public Hearing Process Documentation
CERTIFICATION OF HOLDING OF PUBLIC HEARING ON THE 

MAG 2012 FIVE PERCENT PLAN FORPM-10 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA 

I affirm that a public hearing was held jointly by the Arizona Department of Environmental 

Quality and the Maricopa Association of Govermnents (MAG) starting at 5:30p.m. Thursday, 

April12, 2012 at the MAG Offices, Saguaro Room, 302 North 1 ''Avenue, Phoenix, Arizona and 

that the hearing was held in accordance with the Arizona open meeting laws and 40 CFR 51.102 (d) 

to receive public comment on the MAG 2012 Five Percent Plan for PM-1 0 for the Maricopa County 

Nonattainment Area. 

Lindy Baus · G 

Environmental Director 

STATE OF ARIZONA ) 

) ss. 

COUNTY OF MARICOPA ) 

Personally appeared before me the above-named Lindy Bauer known to me to be the same 

person who executed the foregoing instrmnent and to be the Environmental Director for the 

Maricopa Association of Governments and acknowledged to me that she executed the same as her 

free act. 

SUBSCRIBED AND SWORN TO before me on this / .J'f'-' day of April2012. 

• 

OFFICIAL SEAL 

VALERIE DAY 

NOTARY PUBLIC Stale of Arizona 

MARICOPA COUNTY 

My Comm. Expires Aug. 16, 2012 

My Commission Expires: 

~~a dO/ :z.__ 

Notary Pubhc 
AFFIDAVIT OF PUBLICATION 

THE ARIZONA REPUBLIC 

STATE OF ARIZONA } 

COUNTY OF MARICOPA SS. 

Tabitha Antoniadis, being first duly sworn, upon oath 

deposes and says: That she is a legal advertising 

representative of the Arizona Business Gazette, a 

newspaper of general circulation in the county of Maricopa, 

State of Arizona, published at Phoenix, Arizona, by Phoenix 

Newspapers Inc., which also publishes The Arizona 

Republic, and that the copy hereto attached is a true copy of 

the advertisement published in the said paper on the dates as 

indicated. 

The Arizona Republic 

March 12, 13, 2012 

Sworn to before me this 

147

H day of 

March A.D. 2012 

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MARICOPA 

ASSOCIATION of 

GOVERNMENTS 302 North 1st Avenue, Suite 300 .t. Phoenix, Arizona 85003 

Phone (6021 254-6300 A FAX (8021 254-6490 

E-mail: mag@azmag.gov A Web site: www.azmag.gov 

March 12,2012 

TO: 

FROM: 

SUBJECT: 

Interested Parties for Air Quality 

Lindy Bauer, Environmental Director 

PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN FOR PM-10 

FOR THE MARICOPA COUNTYNONATTAINMENT AREA 

Public Hearing 

Apri112, 2012 at 5:30p.m. 

MAG Offices, Saguaro Room 

302 North 1 '' Avenue, Second Floor 

Phoenix, Arizona 85003 

The Arizona Department of Environmental Quality and Maricopa Association of Governments 

(MAG) will jointly conduct a public hearing on the Draft MAG 2012 Five Percent Plan for PM-1 0 

for the Maricopa County Nonattainment Area on April 12, 2012 at 5:30p.m. The purpose of this 

hearing is to receive public comments. 

According to Section 189 (d) of the federal Clean Air Act, the Five Percent Plan for PM-1 0 is 

required to be submitted to the Environmental Protection Agency. The plan contains a wide variety 

of existing control measures and projects that have been implemented to reduce PM-1 0 and a new 

measure to reduce PM-10 during high risk conditions, including high winds. The measures apply 

to unpaved roads and shoulders, leaf blowers, unpaved parking lots, vacant lots, sweeping streets 

with certified sweepers, off-road vehicle use, open and recreational burning, residential 

woodburning, covered vehicle loads, dust generating operations, nonmetallic mineral processing, 

and other unpermitted sources. The plan demonstrates that the measures will reduce PM-10 

emissions by at least five percent per year and demonstrates attainment of the PM-1 0 standard as 

expeditiously as practicable, which is 2012. 

For your information and convenience, a copy of the public hearing notice is enclosed. The draft 

document is available for public review at the MAG Offices, third floor, from 8:00a.m. to 5:00p.m. 

Monday through Friday. In addition, the draft document is available for agency and public review 

on the MAG website at www.azmag.gov. 

Attachment 

A Voluntary Association of Local Governments in Maricopa County 

City of Apache Junction A City of Avondale ..._Town of Buckeye .t. Town of Carefree .t. Town of Cave Creek .t. City of Chandler .to. City of El Mirage .t. Fort McOO\\Iell Yavapai Nation 4 Town of Fountain Hills "-Town of Gila Bend 

Gila River Indian Community .1o. Tovm of Gilbert .t. City of Glendale • City of Gaodyear A Tovm of Guadalupe J. City of litchfield Park .t. Maricapa County A City of Mesa A Town of Parad"ISe VaUey .A. City of Peoria .A. City of Phoenix 

Town of Oueen Cr£ek .A. Satt River Pima-Maricopa Indian Community .A. City of Scottsdale .A. City of Surprise .A. City of Tempe • City ofToi!esan .A. Tai'm ofWi~kenburg .A. To'Ml ofYoungtovm .A. Arizona Department of Transpof'Uitiofl 
PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE 

MARICOPA COUNTY NONATTAINMENT AREA 

Aprili2, 20I2 at 5:30p.m. 

MAG Offices, Saguaro Room 

302 North I'' Avenue, Second Floor 

Phoenix, Arizona 85003 

The Arizona Department of Environmental Quality (ADEQ) and Maricopa Association of 

Governments (MAG) will jointly conduct a public hearing on the Draft MAG 2012 Five Percent 

Plan for PM-10 for the Maricopa CountyNonattainment Area on April12, 20I2 at 5:30p.m. The 

purpose of this hearing is to receive public comments. 

According to Section I89 (d) of the federal Clean Air Act, the Five Percent Plan for PM -I 0 is 

required to be submitted to the Environmental Protection Agency (EPA). The plan contains a wide 

variety of existing control measures and projects that have been implemented to reduce PM-I 0 and 

a new measure to reduce PM-I 0 during high risk conditions, including high winds. The measures 

apply to unpaved roads and shoulders, leaf blowers, unpaved parking lots, vacant lots, sweeping 

streets with certified sweepers, off-road vehicle use, open and recreational burning, residential 

woodburning, covered vehicle loads, dust generating operations, nonmetallic mineral processing, 

and other unpermitted sources. The plan demonstrates that the measures will reduce PM-1 0 

emissions by at least five percent per year and demonstrates attainment of the PM-IO standard as 

expeditiously as practicable, which is 20I2. 

The draft document is available for public review at the MAG Offices, third floor, from 8:00a.m. 

to 5:00p.m. Mondaytlu·ough Friday and on the MAG website at www.azmag.gov. Public comments 

are welcome at the hearing, or may be submitted in writing by 5:30p.m. on April12, 2012 to Lindy 

Bauer at the address below. After considering the public comments, the MAG Regional Council 

may take action on the plan on May 23,2012. The ADEQ may then adopt the plan for submittal to 

the EPA. 

Contact Person: Lindy Bauer, MAG (602) 254-6300 

302 N. 1" Avenue, Suite 300 

Phoenix, AZ 85003 

Fax: (602) 254-6490 

E-mail: lbauer@azmag.gov 
MARICOPA 

ASS'CCIATICN of 

GOVERNMENTS 

March I2, 20I2 

Ms. Cynthia Zwick 

Director 

Arizona Community Action Association 

2700 North 3rd Street, Suite 3040 

Phoenix, Arizona 85004-II22 

Dear Ms. Zwick: 

TilLE VI 

LETTER EXAMPLE 

302 North 1st Avenue, Suite 300 A Phoenix, Arizona 85003 

Phone [6021 254-6300 A FAX [6021 254-6480 

E-mail: mag@azmag.gov A Web site: www.azmag.gov 

You are cordially invited to a public hearing on the Draft MAG 20 I2 Five Percent Plan for PM-I 0 for 

the Maricopa County Nonattainment Area. The hearing will be held jointly by the Arizona Department 

of Environmental Quality and Maricopa Association of Governments on Thursday, Aprili2, 20I2 at 

5:30p.m. in the Saguaro Room at the MAG Offices, 302 North pt Avenue, Second Floor, Phoenix, 

Arizona, 85003. The purpose of this hearing is to receive public comments. Written and verbal 

comments are welcomed at the public hearing. After considering public comments, the MAG Regional 

Council may take action on the plan on May 23, 20I2. 

According to Section I89 (d) of the federal Clean Air Act, the Five Percent Plan for PM~ I 0 is required 

to be submitted to the Environmental Protection Agency. The plan contains a wide variety of existing 

control measures and projects that have been implemented to reduce PM-I 0 and a new measure to 

reduce PM -I 0 during high risk conditions, including high winds. The measures apply to unpaved roads 

and shoulders, leafblowers, unpaved parking lots, vacant lots, sweeping streets with certified sweepers, 

off-road vehicle use, open and recreational burning, residential woodburning, covered vehicle loads, 

dust generating operations, nonmetallic mineral processing, and other unpermitted sources. The plan 

demonstrates that the measures will reduce PM-I 0 emissions by at least five percent per year and 

demonstrates attainment ofthe PM-IO standard as expeditiously as practicable, which is 20I2. 

The draft document is available for review at the MAG Offices, third floor, from 8:00 a.m. to 5:00p.m. 

Monday through Friday. In addition, the draft document is available for agency and public review on ) 

the MAG website at www.azmag.gov. We hope to see you or your representative at the hearing and 

to include your input in future planning efforts. For your convenience, a copy of the public hearing 

notice is attached. If you have any questions or would like to set up a time for us to meet with your 

organization, please call me at (602) 254-6300. 

Sincerely, 

~~~· BCAAJJA_,/ .. 

Lindy Bauer 

Environmental Director 

Attachment 

A Voluntary Association of Local Governments in Maricopa County 

City of Apanhe Junntion A City of Avondale A Town of Buckeye A Town of Carefree A Town of Cave Creek A City of Chandler A City of E1 Mirage A Fort McDowell Yavapai Nation A Town of Fountain Hills A Town of Gila Bend 

Gila River Indian Community A Town of Gilbe£A City of Glendale A. City of Goodyear A Town of Guadalupe A City of Litchfield Park A Marinopa County A City of Mesa A. Town of Paradise Valley A City of Peoria A City of Phoenix 

Town of Queen Creek A Salt River Pima-Maricopa Indian Community A. City of Scottsdale A. City of Surprise A City of Tempe A City of Tolleson A Town of Wickenburg A Town of Youngtown A Arizona Department ofTransportation 
PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE 

MARICOPACOUNTYNONATTAINMENT AREA 

April12, 2012 at 5:30p.m. 

MAG Offices, Saguaro Room 

302 North 1st Avenue, Second Floor 

Phoenix, Arizona 85003 

The Arizona Department of Environmental Quality (ADEQ) and Maricopa Association of 

Governments (MAG) will jointly conduct a public hearing on the Draft MAG 2012 Five Percent 

Plan for PM-10 for the Maricopa County Nonattainment Area on April12, 2012 at 5:30p.m. The 

purpose of this hearing is to receive public comments. 

According to Section 189 (d) of the federal Clean Air Act, the Five Percent Plan for PM -10 is 

required to be submitted to the Environmental Protection Agency (EPA). The plan contains a wide 

variety of existing control measures and projects that have been implemented to reduce PM -10 and 

a new measure to reduce PM -10 during high risk conditions, including high winds. The measures 

apply to unpaved roads and shoulders, leaf blowers, unpaved parking lots, vacant lots, sweeping 

streets with certified sweepers, off-road vehicle use, open and recreational burning, residential 

woodburning, covered vehicle loads, dust generating operations, nonmetallic mineral processing, 

and other unpermitted sources. The plan demonstrates that the measures will reduce PM-10 

emissions by at least five percent per year and demonstrates attainment of the PM-10 standard as 

expeditiously as practicable, which is 2012. 

The draft document is available for public review at the MAG Offices, third floor, from 8:00a.m. 

to 5:00p.m. Monday through Friday and on the MAG website at www.azmag.gov. Public comments 

are welcome at the hearing, or may be submitted in writing by 5:30p.m. on April12, 2012 to Lindy 

Bauer at the address below. After considering the public comments, the MAG Regional Council 

may take action on the plan on May 23, 2012. The ADEQ may then adopt the plan for submittal to 

the EPA. 

Contact Person: Lindy Bauer, MAG (602) 254-6300 

302 N. 1st A venue, Suite 300 

Phoenix, AZ 85003 

Fax: (602) 254-6490 

E-mail: lbauer@azmag.gov 
MARICOPA 

ASSOCIATION of 

GOVERNMENTS---------------

302 North 1st Avenue, Suite 300 J.. Phoenix, Arizona 85003 

Phone (602) 254-6300 J.. FAX (6021 254-6490 

E-mail: mag@azmag.gov J.. Web site: www.azmag.gov 

March 12, 2012 

TO: 

FROM: 

SUBJECT: 

Leslie Rogers, Federal Transit Administration 

Karla Petty, Federal Highway Administration 

John Halikowski, Arizona Department of Transportation 

Henry Darwin, Arizona Department of Environmental Quality 

Neal Young, City of Phoenix Public Transit Department 

Stephen Banta, METRO/RPTA 

William Wiley, Maricopa County Air Quality Department 

Brian Tapp, Central Arizona Association of Governments 

Donald Gabrielson, Pinal County Air Quality Control District 

Gregory Nudd, U.S. Environmental Protection Agency, Region IX 

Lindy Bauer, Environmental Director 

TRANSMITTAL OF THE DRAFT MAG 2012 FIVE PERCENT PLAN FOR PM-10 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA 

The Maricopa Association of Governments has prepared a Draft MAG 2012 Five Percent Plan for 

PM-1 0 for the Maricopa County Nonattainment Area. The draft document is available for review at 

the MAG Offices, third floor, from 8:00a.m. to 5:00p.m., Monday through Friday. In addition, the 

draft document is available for agency and pubiic review on the MAG website. Any comments are 

requested by 5:30p.m. on April12, 2012. 

According to Section 189 (d) of the federal Clean Air Act, the Five Percent Plan for PM -10 is required 

to be submitted to the Environmental Protection Agency (EPA). The plan contains a wide variety of 

existing control measures and projects that have been implemented to reduce PM-1 0 and anew measure 

to reduce PM-10 during high risk conditions, including high winds. The measures apply to unpaved 

roads and shoulders, leaf blowers, unpaved parking lots, vacant lots, sweeping streets with certified 

sweepers, off-road vehicle use, open and recreational burning, residential woodburning, covered vehicle 

loads, dust generating operations, nonmetallic mineral processing, and other unpermitted sources. The 

plan demonstrates that the measures will reduce PM-1 0 emissions by at least five percent per year and 

demonstrates attainment of the PM-10 standard as expeditiously as practicable, which is 2012. 

On April 12, 2012, a public hearing will be held jointly by the Arizona Department of Environmental 

Quality (ADEQ) and MAG at the MAG Offices, Saguaro Room, Second Floor, Phoenix, Arizona at 

5:30p.m. After considering public comments, the MAG Regional Council may take action on the plan 

on May 23, 2012. The ADEQ may then adopt the plan for submittal to the EPA. If you have any 

questions, please do not hesitate to contact me at (602) 254-6300. 

cc: Eric Massey, Arizona Department of Environmental Quality 

Scott Orner, Arizona Department of Transportation 

A Voluntary Association of Local Governments in Maricopa County 

City of Apache Junction J.. City of Avondale J.. Town of Buckeye J.. Town of Carefree J.. Town of Cave Creek J.. City of Chandler J.. City of El Mirage J.. Fort McDowell Yavapai Nation J.. Town of Fountain Hills A. Town of Gila Bend 

Gila River Indian Community J.. Town of Gilbert J.. City of Glendale J.. City of Goodyear J.. Town of Guadalupe J.. City of Utchfield Park J.. Maricopa County J.. City of Mesa J.. Town of Paradise Valley J.. City of Peoria J.. City of Phoenix 

Town of Queen Creek J.. Salt River Pima-Maricopa Indian Community J.. City of Scottsdale J.. City of Surprise J.. City of Tempe J.. City of Tolleson J.. Town of Wickenburg J.. Town of Youngtown J...Arizona Department of Transportation 
PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE 

MARICOPACOUNTYNONATTAINMENT AREA 

April12, 2012 at 5:30p.m. 

MAG Offices, Saguaro Room 

302 North P1 Avenue, Second Floor 

Phoenix, Arizona 85003 

The Arizona Department of Environmental Quality (ADEQ) and Maricopa Association of 

Governments (MAG) will jointly conduct a public hearing on the Draft MAG 2012 Five Percent 

Plan for PM-10 for the Maricopa County Nonattainment Area on Aprill2, 2012 at 5:30p.m. The 

purpose ofthis hearing is to receive public comments. 

According to Section 189 (d) of the federal Clean Air Act, the Five Percent Plan for PM -10 is 

required to be submitted to the Environmental Protection Agency (EPA). The plan contains a wide 

variety of existing control measures and projects that have been implemented to reduce PM -10 and 

a new measure to reduce PM -10 during high risk conditions, including high winds. The measures 

apply to unpaved roads and shoulders, leaf blowers, unpaved parking lots, vacant lots, sweeping 

streets with certified sweepers, off-road vehicle use, open and recreational burning, residential 

woodburning, covered vehicle loads, dust generating operations, nonmetallic mineral processing, 

and other unpermitted sources. The plan demonstrates that the measures will reduce PM-10 

emissions by at least five percent per year and demonstrates attainment of the PM-10 standard as 

expeditiously as practicable, which is 2012. 

The draft document is available for public review at the MAG Offices, third floor, from 8:00a.m. 

to 5:00p.m. Monday through Friday and on the MAG website at www.azmag.gov. Public comments 

are welcome at the hearing, or maybe submitted in writing by 5:30p.m. onApril12, 2012 to Lindy 

Bauer at the address below. After considering the public comments, the MAG Regional Council 

may take action on the plan on May 23,2012. The ADEQ may then adopt the plan for submittal to 

the EPA. 

Contact Person: Lindy Bauer, MAG (602) 254-6300 

302 N. 151 Avenue, Suite 300 

Phoenix, AZ 85003 

Fax: (602) 254-6490 

E-mail: lbauer@azmag.gov 
MARICOPA ASSOCIATION OF GOVERNMENTS

ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY

PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN

FOR PM-10 FOR THE MARICOPA COUNTY NONATTAINMENT AREA

Phoenix, Arizona

April 12, 2012

5:30 p.m.

Prepared By: Prepared By:

Maricopa Association of Governments KARA JOHNSON

(Original) Administrative Assistant
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I N D E X

PUBLIC SPEAKERS: PAGE

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MARICOPA ASSOCIATION OF GOVERNMENTS

ARIZONA DEPARTMENT OF ENVIRONMENTAL QUALITY

PUBLIC HEARING ON THE MAG 2012 FIVE PERCENT PLAN

FOR PM-10 FOR THE MARICOPA COUNTY NONATTAINMENT AREA

commenced at 5:30 p.m. on April, 12, 2012 at the offices of

Maricopa Association of Governments, 302 North First Avenue,

Suite 300, Phoenix, Arizona before KARA JOHNSON, Administrative

Assistant for the Environmental Division of Maricopa Association

of Governments. 

 * * * * * 

A P P E A R A N C E S

Maricopa Association of Governments:

Lindy Bauer

Cathy Arthur

Arizona Department of Environmental Quality:

Eric Massey
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Phoenix, Arizona

April 12, 2012

5:30 p.m.

PROCEEDINGS

MS. BAUER: I’d like to welcome everyone to our public

hearing this evening. My name is Lindy Bauer and I am the

Environmental Director with MAG. 

This public hearing is being held jointly by the Arizona

Department of Environmental Quality and the Maricopa Association of

Governments to receive public comments on the Draft MAG 2012 Five

Percent Plan for PM-10 for the Maricopa County Nonattainment Area.

MAG serves as a designated regional air quality planning

agency. Our regional air quality plans are prepared through a

coordinated effort with the Arizona Department of Environmental

Quality, Maricopa County Air Quality Department, and the Arizona

Department of Transportation. 

Those driving to the meeting this evening, who parked in

the garage, can have their tickets validated by the MAG staff.

Kara has the validation for the parking tickets.

Now the public hearing this evening will begin with some

introductory remarks by the Arizona Department of Environmental

Quality and then there will be an overview presentation by the MAG

staff. Following the presentation hearing participants are invited
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to make comments for the public record. A record of the public

hearing will be prepared. Written comments are also welcome at

this public hearing. 

For those participants wishing to speak, please fill out

a form on the table and place it in the box. 

If you need to leave early because of a bus schedule,

please tell the MAG staff; and we will accommodate your request. 

As you come up to the podium, please state some

information for the record: your name and who you represent. 

I would like to note that we have a timer to assist the

public with their presentations. We have a three minute time

limit. When two minutes have elapsed, the yellow light will come

on, notifying the speaker that they have one minute to sum up. At

the end of the three minute time period, the red light will come

on. 

And now I would like to introduce Eric Massey, the

Director of the Air Quality Division at the Arizona Department of

Environmental Quality.

MR. MASSEY: Thank you, Lindy. 

I will try to keep my comments pretty brief, but what I

wanted to acknowledge was that today’s activities are really the

culmination of the efforts of many people, through our stakeholder

process that ran through the entirety of 2011. The process was cochaired by Representative Amanda Reeve and also our Director Henry

Darwin and included a number of efforts from the people that were
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in our stakeholder group which also included Maricopa County, MAG,

ADEQ staff. And so I wanted to take just a moment to appreciate

the efforts of everybody that was involved because we were meeting

sometimes twice a month trying to come up with a solution to the

issues that EPA had addressed in-- or had raised in its proposed

partial approval/partial disapproval back in 2010. 

For me, the project is one of collaboration. It’s a real

source of pride for me because I think we’ve had a chance to work

closely together as regulatory entities with our regulated

community to find a solution to a problem that has persisted here

in the valley for a very long time. And what I really liked about

our major efforts, was the collaboration, specifically between

ADEQ, MAG, Maricopa County, and even EPA as we work through some of

the technical meetings that occurred behind the scenes, once every

two weeks for nearly the entirety of 2011.

So there was a tremendous amount of technical effort that

went into this, a tremendous amount of effort from all of the

stakeholders involved and I think the result is a really effective

piece of work. And the other piece that I really like, about what

we’ve done in this plan, is that we built upon prior efforts. One

of the things that was important to MAG, to Maricopa County, to

ADEQ through this whole process is that we were, um, cognizant of

the efforts that went into 2007's Senate Bill 1552 and that we

didn’t wipe out the benefits that really came from that rule. 

Some of the things that we have seen is just a declining
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concentration of PM-10 here in Phoenix. And while there has been

some work to do and some issues like exceptional events that have

clouded our issues; there has been a tremendous amount of effort

that’s been done throughout the entire air shed. And we really

wanted to take a moment to acknowledge that and notice that we’re

building on past efforts. 

We also have some really new innovative ideas that are

part of this plan, some of the forecasting that DEQ is doing, the

Dust Action General Permit which came as a collaborative effort

from all of us here, to really find a solution to the ongoing

issues of high wind days and its just a great opportunity to kind

of meld the past effort with new thinking and its been a true honor

for me to have been involved in this particular process. I’m

looking forward to the continued process that goes through with EPA

review and working together with our partners to make sure that

this plan itself is one that can be approved. 

With that Lindy, I just wanted to say thank you again and

the opportunity to be here today. And this is really a tremendous

effort and I think a day to be celebrated.

MS. BAUER: Thank you very much, Eric. We really

appreciate all of your efforts as well as the efforts of all of the

stakeholders that worked with us and Representative Reeve’s

leadership as well. So, thank you for your comments. 

And now we will have an overview presentation on the MAG

2012 Five Percent Plan for PM-10.
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Cathy Arthur with the Maricopa Association of

Governments.

MS. ARTHUR: Thank you, Lindy and Eric.

This is an overview of this plan. And as those of you

have read it know, that it would probably take quite some time to

go into a lot of detail so we are just going to do the highlights

and hopefully look at the very important points that this plan

represents. 

The new plan has a large number of control measures that

address a variety of sources and many of these have already been

implemented. In fact, most of them were in the 2007 Five Percent

Plan- there were 53 measures in that plan. And although that plan

was withdrawn in January of 2011 by the Arizona Department of

Environmental Quality, most of those measures continue to be

implemented. And we are resubmitting many of those measures in

table 4-1 of the plan. 

There is one new measure in this plan and it focuses on

high wind events. And this is generally because our 2007 plan

focused on stagnant conditions and PM-10 exceedances during those

conditions. So we needed to look at additional measures that would

help us control PM-10 levels during high wind events and this plan

does that. 

There have been no violations of the PM-10 standard

under stagnant conditions since the 2007 plan was submitted in

December 2007. So we feel the plan that we submitted was very
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effective-- the control measures were very effective with respect

to PM-10 violations under stagnant conditions, but we needed to do

additional work under high wind events. 

Just to show you some of the sources that we are

controlling through the measures in this 2012 Five Percent Plan and

you can see there is a large variety of sources, including:

trackout, open burning, unpaved shoulders, unpaved roads, vacant

lots, earthmoving activities, ATV’s, weed abatement operations,

leaf blowing activity, street sweeper requirements- PM-10 Certified

Street Sweepers, and then nonmetallic mineral processing operations

are all being controlled through the measures that are in the 2012

plan. 

In terms of monitoring data and this is a fairly

complicated bar graph here, we can focus on the fact that in 2010,

there was only one exceedance of the PM-10 standard. 

In 2011, however, you will see that there are 22; 21 of

those, however, we feel are exceptional events. Now an exceptional

event is an uncontrollable natural event, which here in the Phoenix

area tends to be high wind caused. ADEQ is in the process of

documenting 21 exceptional events that occurred in 2011 and in

addition we will be working on seven of them that are in purple

here for 2009. 

Just to add a little information, in 2012 we have already

had 3 days that would be considered in purple, so there is going to

have to be documentation of those as well by DEQ. And MAG and the
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Maricopa County Air Quality Department are working with DEQ to

prepare that documentation which is very time consuming, but it is

necessary for us to show attainment by 2012.

This is a pie chart that shows you the total emissions of

PM-10 in the nonattainment area in 2008 and it totals about 50,000

tons per year. And the top two contributors in 2008, which is the

first year of the plan, were unpaved roads at 24 percent and if you

add up all the construction activities- 17 percent. So those are

the top two in 2008. Keep those in mind because it changes by the

time we get to the attainment year of 2012. Not only do the

emissions go down, but the sources that contribute the most are

different.

The 2012 Five Percent Plan relies on a number of measures

in order to demonstrate five percent reductions and show reductions

due to contingency measures. And the most important one in terms

of the five percent reductions is increasing rule effectiveness for

three rules that Maricopa County Air Quality Department has passed.

And EPA has approved these rules. 

Rule 310, which is for dust generating operations, such

as earthmoving.

Rule 310.01, which is for sources of nontraditional dust,

such as unpaved roads, vacant lots, and unpaved parking lots. 

And Rule 316, which is nonmetallic mineral processing,

which is for mining and sand and gravel operations.

So those just give you an idea of the types of sources
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covered by these rules. 

Compliance with these rules has increased every year

since 2007 and that is being measured by the county using a method

that was approved by EPA. 

So we are using the increases in compliance with these

three rules to demonstrate five percent reductions per year. And

we are also using the new Dust Action General Permit, which I will

talk about in a minute. 

The other bullet points here- PM-10 certified street

sweeping, road/alley/shoulder paving and stabilization projects,

speed limit reductions, and rubberized asphalt overlay- are all

measures that have been accomplished. In other words, they are

projects that have been completed and we are taking credit for

those as contingency measures. 

Now I mentioned that we have one new measure called the

Dust Action General Permit that addresses high wind events. And

the Dust Action General Permit identifies best management practices

that need to be implemented before and during a high risk event.

And ADEQ is going to give the sources-- hopefully up to five days

of notice, when a high risk day is going to occur. And then they

are going to expect sources that are uncontrolled to implement at

least one best management practice before and during that event.

The Dust Action General Permit was passed by the legislature in

April 2011 and went into full effect on January 1, 2012. 

Now I am just going to go over briefly what the
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requirements are for a five percent plan under section 189(d) of

the Clean Air Act. First of all it requires five percent

reductions per year and in our case we are saying attainment is

going to be achieved in 2012. So we need to show five percent per

year in 2008, 2009, 2010, 2011, and 2012. 

So if we look at the base year emissions in 2007, it is

actually close to 60,000 tons and we multiply that by five percent;

that tells us what amount of reduction, about three thousand tons

that you need each year for five years. So our target is almost 15

thousand tons, over that period.

And you can see from the second bullet point, um, under

total PM-10 emissions that we’ve been able to achieve by applying

increased rule effectiveness for those three rules, plus the Dust

Action General Permit. We have been able to achieve a reduction to

43,000 tons which means that we exceed the requirement by 1,284

tons or nine percent. So we have been able to meet that five

percent reduction requirement. 

Now I also mentioned that there are measures or projects

that have been implemented which will achieve the requirement for

contingency. And the Clean Air Act requires this as well and EPA

gives you guidance as to how much you should achieve in the way of

tonnage reduction and it’s one year of reasonable further progress,

which turns out to be about 3,000 tons. And so you need to show

that you are reducing 3,000 tons more than you did in order to

achieve the five percent reductions. There are quite a few
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projects that have been implemented and I will show you a table in

a minute and with all of those projects- which cover paving,

stabilization, speed limit reduction, and street sweeping- we are

able to achieve 3,400 tons. So, we are 220 tons higher than we

need to be to achieve the contingency requirement. 

Now this slide is just a summary of all of the projects

that were completed-- and by the way these were all completed by

September 2011 so that way we knew they had been open to traffic

when we produced this plan. You can see just as a summary the

total miles of roads and alleys that have been paved and stabilized

over the period of 2008 to 2011 is 862 miles. So quite a lot of

mileage has been stabilized and of course that significantly

reduces PM-10. And then the other major statistic here is the

total miles of shoulders paved and stabilized over that same period

which is 1,158. So between the shoulder and the road

paving/stabilization we are able to achieve a very large percentage

of what we needed for the contingency requirement. 

On the next page it shows you that the benefit we took

for PM-10 Certified Street Sweeping-- there are really two aspects

to this, ADOT signed a contract on February 20, 2010 which requires

their contractor that’s sweeping freeways, ramps and frontage roads

in the PM-10 nonattainment area to use PM-10 Certified Street

Sweepers. Most of the credit, is due to that, but in addition

there were 27 PM-10 Certified Street Sweepers purchased between

2007 and 2009 with Congestion Mitigation Air Quality Improvement
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funds through MAG. Those are being used to sweep arterials in the

PM-10 nonattainment area.

Here is another pie chart. Now this one is for 2012 and

so I told you to keep in mind what the top two contributors were in

2008 before a lot of these measures were taken into consideration

and now we are showing really the highest contributor is paved

roads and unpaved roads which was the highest before is now second

at 19 percent. So the percentages change, but more importantly the

total amount of tons contributed is down almost 10,000, between

2007 and 2012. This is how we are able to achieve the reductions

that we need for both five percent per year and contingency. 

So in conclusion the plan meets the five percent

reduction requirement, the contingency requirement,-- something I

haven’t talked about is that EPA requires that your plan

demonstrate through modeling that you can attain this standard in

2012 as well. There were two days that we modeled, both high PM-10

and high wind days and one was May 4, 2007 and the other June 6,

2007 and we were able to show attainment in 2012 for both of those

scenarios using the same measures that we did to show the five

percent reductions which is the increase in rule effectiveness and

the Dust Action General Permit. So, those things allowed us show

attainment through modeling as well as for five percent reductions.

Now this plan also includes a request to extend the

attainment date for a little over six months- from June 6, 2012,

which is the date that we were required to meet the five year
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extension past 2006. And, we are asking for an extension because

the Dust Action General Permit was not implemented fully until

January 1, 2012 and we really need a whole year of benefit for the

high wind days in order to be able to demonstrate attainment

through modeling. So that’s why we are asking for this six month

extension. 

Now in general the overall reduction as I mentioned is

about 10,000 tons which is about a third, versus 2007 emissions.

The reductions are due to the broad sweeping measures for many,

many sources that were included in this plan. And then perhaps

most importantly, the bottom line here, is that we need three years

of clean data at the monitors, in 2010, 2011, and 2012 in order to

demonstrate attainment in the real world as opposed to through this

plan. Of course that is going to be dependent on exceptional event

documentation that DEQ is preparing for 2011 and 2012. So EPA will

need to concur with our documentation in order for us to be able to

show attainment and we are hopeful that we will not have any more

days in the remainder of 2012, but there are a few months left to

go. If they are exceptional events that will put a burden again on

us to document them. But we will be up to the task. 

And then finally, this is the schedule that we are under

for this plan. The plan was released for public review on March

the 12th and today is the public hearing. In two weeks we will go

to our Air Quality Technical Advisory Committee and ask for a

recommendation and then we will be going to the Management
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Committee the first part of May. Assuming those two committees

recommend that this plan go forward then the Regional Council will

adopt the plan on May 23rd. And then at that point we turn the plan

over to DEQ and they submit the plan to EPA. 

Two other important dates- August 14 th of 2012 is the

deadline, about two and a half months we are going to give EPA to

find this plan to be complete. If they do that by this date, then

that will stop the sanction clocks that are currently ticking. The

18 month and 24 month sanction clocks are ticking right now because

we withdrew the 2007 plan. And then February 14 th of 2013 is the

deadline for EPA to approve the plan, not just find it complete,

but approve all the control measures and all the other things that

were fulfilled in the plan in order to avoid EPA developing a

federal implementation plan. 

That completes my overview here and I think we will turn

it over to Lindy to entertain comments. 

MS. BAUER: Okay, Thank you very much, Cathy.

And now for the public comment period. 

PUBLIC COMMENTS

MS. BAUER: At this time public comments are welcome at

the hearing. Again, if you would like to speak, please fill out

a speaker form and place it in the box and please adhere to the

three minute time limit. We have the speaker forms over here, to
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the left.

So first we have a speaker form from Jerry Greenberg.

MR. GREENBERG: Hello, my name is Jerry Greenberg and I

am from Chandler. Uh, first of all I would like to thank you for

all of your hard work, for those of you who have been involved in

this; I really appreciate it. 

Let me tell you a little about who I am and why in the

world I am here in the middle of rush hour and everything else to

participate in this meeting. 

I have kind of an interesting background. I am a

retired registered nurse. I am also a retired Air Force officer,

served our Country during two wars and believe it or not, I was a

first responder to both the Oklahoma City bombing and 9/11 at the

Pentagon. As a result, my lungs were affected because needless

to say none of us were protected against everything that was in

the air. Particularly pieces of building, fiberglass, you name

it, including literally glass fibers, um, that we all inhaled. 

As a result, I am kind of sensitive and I had no idea when we

moved here from the east coast, in 2007, that perhaps my lung

sensitivity would come to the forefront. However, they did.

Last, we bought a foreclosed home, sunk a bit of our

life savings into it in Chandler in just a regular, nice

neighborhood. Last fall, after living in the home for about a

year and a half I was having trouble breathing. And so I went to

the doctor and they kind of checked me out, did a chest X-ray,
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that kind of thing. On my way back I stopped at the intersection

of McClintock and Chandler. It was a little bit windy and I

looked over to my right, with, and its all vacant lots on the

north of that area and dust was just blowing like crazy right

into my neighborhood. And so I thought perhaps-- okay, you know

where I am going from there. I looked around and I realized my

neighborhood, Twelve Oaks, Stellar Air Park, that neighborhood

there is surrounded-- I have one minute left? Okay-- is

surrounded by dirt lots. So all of sudden I became interested. 

I called the City; I called the County, and made formal

complaints which were responded to. However, frankly if I kept

my front yard like the people keep the vacant lots that they

owned, I’d be fined, but yet people are allowed to dump

construction dirt on these-- in these lots. They are allowed to

dump construction debris. They are allowed to just let it be

bare dirt, literally bare dirt, on these lots. And, so, what I

would ask of you is why are we coddling these vacant lot owners? 

The economic recovery is well, you know, going on and another is

would you please, maybe you are doing this and I don’t know,

monitor residential areas for PM-10 and then report on them. 

Can I go over just a little bit?

I have a new grandson who was born at Chandler Regional

Hospital. On the way, on Frye Road, which was at sunset, I saw

huge tractor with a plow on the back of it, raising huge clouds

of dust half mile from where my grandson is and I called the City
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the next day. They said we’ll talk to him about it and they said

he’ll stop doing that. Thank you, he should have known not to do

that and he did it at sunset because he knew that all the offices

were closed. 

We can’t have that kind of thing going on in a City. 

Chandler is over 250,000 residents and yet this is the kind of

thing that is going on. I can’t speak for Glendale, or any place

else, I can only speak for the City I live in and so what I would

ask you is, please continue to enforce this. Lobby the State,

the Government, to really be stronger on this and help us to grow

up as a community, so that it can be healthier.

Thank you. 

MS. BAUER: Thank you very much. Next we have Sandy

Bahr.

MS. BAHR: Hi, good afternoon. Thank you for the

opportunity to speak this afternoon. My name is Sandy Bahr; I am

the Chapter Director for the Sierra Club here in Arizona. And I

live in Phoenix and in the PM-10 nonattainment area and have

lived in the PM-10 nonattainment area ever since there has been

one. Because as far as I know ever since there has been one we

haven’t met the standards. 

Um, as you know PM-10 has been a serious problem in the

Valley for more than two decades and there’s a long history of

inadequate plans being submitted and failure to reach attainment. 

We have raised the issue before about the Maricopa
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Association of Governments not being the right entity for leading

this effort. No offense, I know people work really hard, but I

think politically it is a difficult place to try to get clean air

when the purpose of the organization is really about

transportation and facilitating expenditure of federal highway

dollars. 

A couple of things, specific to-- so that is kind of an

overarching comment and I don’t expect that MAG will address that

one, but I just wanted to make sure that you were aware that we

continue to have that concern. 

One of the issues that I wanted to raise this afternoon

is this issue of three years of clean data and the fact that you

are looking at seeking to identify 21 of the 22 exceedances for

2011 as exceptional events. Uh, I think by anyone’s common sense

definition, when you start having that many exceptional events

they fail to be exceptional, and we strongly question that. We

have, I know-- probably used most of my time so I’ll try to be

quick. We are submitting some written comments. 

The other thing is this plan is supposed to demonstrate

best available control measures and maximum measures as well and

we didn’t see where you had demonstrated that in the plan. And,

so, I would love for someone to point that out, but I believe you

have to demonstrate in the plan as well. 

One thing we have raised before, and it just doesn’t

make a whole lot of sense-- from just when you think about a
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contingency measure? How can it be a contingency measure if its

already implemented. Contingency measures are supposed to be

for, you know, if something else doesn’t work, you have a

contingency. And what has happened with a lot of previous

measures is, we are implementing a contingency and then there is

no contingency, right, there is nothing left. And so, we would

like to have you take a look at that as well. 

Finally, we just continue to have concerns about

enforcement and I think the gentleman before me raised some of

the issues with that and I know that there have been changes

relative to the BMP’s for agriculture, but I still think there

are good questions about whether those are truly, uh, enforceable

and would like to see more information in the plan on that as

well. And there are some other issues, but I am out of time. 

I appreciate the opportunity. Thank you. 

MS. BAUER: Thank you very much.

Do we have any other forms for people wishing to speak?

Okay, thank you very much. The Maricopa Association of

Governments appreciates your interest in regional air quality and

your comments. Your comments will be presented to the MAG Air

Quality Technical Advisory Committee at the April 26, 2012

meeting at 1:30 p.m. A response to comments will be prepared and

included in the plan documents. 

Again, we thank you for your participation this

evening. 
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(The proceedings concluded at approximately 6:05 p.m.)

MARICOPA 

ASSOCIATION of 

GOVERNMENTS -~30~2~No~rth~1s-t Pl~~~e-nu-e, S~uit-e 3~0o~ ... ~P~hoe~nix~. Ar~iz-ona~B~50~03-­ Phone [602] 254-6300 A FAX [602] 254-6490 

mag@mag.maricopa.gov 

Meeting: Public Hearing on the MAG 2012 FIVE PERCENT PLAN FOR PM-10 

Room: Saguaro Room 

Date: April12. 2012 

PLEASE SIGN IN BELOW: 

NAME ORGANIZATION/ AFFILIATION MAILING ADDRESS 

SRP 
PUBLIC HEARING ON THE 

MAG 2012 FIVE PERCENT PLAN FOR PM-10 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA 

April12, 2012 

Date _y:+-· -F-;:=---.,{),__/~1 )-___ _ 

Name ~e f--1(_ y G (2 e e/"'-b £ f2-1 ----------+~----------(=P~le-as-e=Pr~in~ty~----------------------

Address L--j.) 3 I W ( 0h; c ~j 0 s +- } c/'-ClvvJ l-e~ ~~d)_ (, 

Title Phone ~~ £' 0 .... ? 5-7 - CJ 9 ~ )- ----------------------

Representing, __ __!_/\\_7 V{____J(L_--=-(J.._v_l'-_: __:\-/y-;-::::-__ -:---:-------::----------------------- r I (Organization, etc.) 

Do you wish to be heard? Yes 'r/., No 0 IfN ecessary 0 

*D~ ature 

MARICOPA 

ASSOCIATION of 

GOVERNMENTS 

PUBLIC HEARING ON THE 

MAG 2012 FIVE PERCENT PLAN FOR PM-10 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA 

Do you wish to be heard? Yes )4" 
1

RESPONSE TO PUBLIC COMMENTS ON THE 

DRAFT MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE

MARICOPA COUNTY NONATTAINMENT AREA

APRIL 12, 2012 PUBLIC HEARING

The Maricopa Association of Governments (MAG) appreciates the comments made during the

public comment period for the Draft MAG 2012 Five Percent Plan for PM-10 for the Maricopa

County Nonattainment Area. An advertised public hearing was conducted on April 12, 2012.

Verbal testimony was presented at the April 12, 2012 public hearing. One submittal of written

comments was received.

COMMENTS FROM JERRY GREENBURG (Testimony at the April 12, 2012 public hearing)

Comment: We bought a foreclosed home, sunk a bit of our life savings into it, in Chandler, in just

a regular, nice neighborhood. Last fall, after living in the home for about a year and a half I was

having trouble breathing. So I went to the doctor and they checked me out, did a chest X-ray, that

kind of thing. On my way back I stopped at the intersection of McClintock and Chandler and it was

a little bit windy and I looked over to my right and its all vacant lots on the north of that area and

dust was just blowing like crazy right into my neighborhood. So I thought perhaps, OK, you know

where I am going, from there. I looked around and I realized my neighborhood, Twelve Oaks,

Stellar Air Park, is surrounded by dirt lots. So all of a sudden I became interested. I called the City,

I called the County, and made formal complaints which were responded to. However, frankly, if

I kept my front yard like the people keep the vacant lots that they owned, I’d be fined, but yet people

are allowed to dump construction dirt on these lots. They are allowed to dump construction debris.

They are allowed to just let it be bare dirt, literally bare dirt, on these lots. What I would ask you

is, why are we coddling these vacant lot owners? The economic recovery is well going on and

another is, would you please, maybe you are doing this and I don’t know, monitor residential areas

for PM-10 and then report on them?

Response: Thank you for your concern. Fugitive dust produced by vacant lots is regulated under

Maricopa County Air Pollution Control Rule 310.01, Fugitive Dust from Non-Traditional Sources

of Fugitive Dust. http://www.maricopa.gov/aq/divisions/planning_analysis/rules/docs/310.01.pdf.

The Rule requires the owner and/or operator of a vacant lot to keep the soil stabilized at levels that

pass tests specified in the rule. A stabilized surface can appear to be bare dirt. Control measures

commonly utilized include applying dust suppressants, establishing vegetative ground cover, and

covering the surface with gravel. 

All County Dust Control inspectors have been trained to inspect vacant lots and regularly conduct

proactive as well as complaint inspections throughout Maricopa County. Between 2008 and 2010,

Maricopa County conducted a total of 21,753 vacant lot inspections. Given the size of the County

and the large number of vacant lots, Maricopa County Air Quality Department (MCAQD)

encourages residents to call and report any problem vacant lot or dust creating activity such as illegal
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dumping. To report a violation, call (602)372-2703 or log onto

http://www.maricopa.gov/aq/contact_us/ReportViolation.aspx.

Vehicles traveling or parking on vacant lots (e.g., to dump construction dust or debris) are also

restricted by both County and local government ordinances. The City of Chandler has an ordinance

that restricts vehicular use and parking on vacant lots. If you observe vehicles traveling or parking

on vacant lots in your neighborhood, call City of Chandler Code Enforcement at (480) 782-4320.

The Maricopa County Air Quality Department operates a monitoring network with a number of

monitors sited to measure particulate matter at the neighborhood scale where residents live. Other

monitors represent various source types and profiles common in the county such as industrial,

commercial, etc. Monitoring data is summarized annually by location in a network review report

submitted to the Environmental Protection Agency. In addition, the department prepares an annual

report that summarizes its compliance inspection and enforcement activity. Both documents are

available on the Maricopa County Air Quality Department website. The network review reports

available at http://www.maricopa.gov/aq/divisions/monitoring/network.aspx and the annual report

at http://www.maricopa.gov/AQ/media/docs/pdf/NewsItemDocs/2011%20-

%20Annual%20Report.pdf.

Comment: I have a new grandson who was born at Chandler Regional Hospital. On the way, on

Frye Road, at sunset, I saw a huge tractor with a plow on the back of it, raising huge clouds of dust,

a half mile from where my grandson is and I called the City the next day. They said they would talk

to him about it and they said oh, he’ll stop doing that. Thank you, he should have known not to do

that and he did it at sunset because he knew that all the offices were closed. We can’t have that kind

of thing going on in a City. Chandler is over 250,000 residents and yet this is the kind of thing that

is going on. I can’t speak for Glendale, or any place else, I can only speak for the City I live in and

so what I would ask you is, please continue to enforce this lobby. The State, the Government, to

really be stronger on this and really help us to grow up as a community, so that it can be healthier.

Response: The Arizona Department of Environmental Quality (ADEQ) is responsible for

controlling dust emissions from agricultural activities in Area A, which includes the Maricopa

County PM-10 nonattainment area. Under Senate Bill 1552, passed by the Arizona Legislature in

2007, farmers are required to implement two best management practices (BMPs) to reduce PM-10

emissions in each of the following categories: tillage and harvest, non-cropland, and cropland.

Additional informa tion on the BMPs can be obtained at

http://www.azdeq.gov/environ/air/plan/download/webguide.pdf. When you observe high levels of

dust being generated by a tractor or vacant parcel that is being farmed, you should call Emily

Bonnani, ADEQ, (602) 771-2324, to issue a complaint. 

COMMENTS FROM SANDY BAHR, SIERRA CLUB IN ARIZONA (Testimony at the April 12,

2012 public hearing)

Comment: We have raised the issue before about the Maricopa Association of Governments not

being the right entity for leading the effort. No offense, I know people work really hard, but I think
3

politically it is a difficult place to try to get clean air when the purpose of the organization is really

about transportation and facilitating expenditure of federal highway dollars. A couple of things, so

that is kind of an overarching comment and I don’t expect that MAG will address that one, but I just

wanted to make sure that you were aware that we continue to have that concern.

Response: The Maricopa Association of Governments serves as the designated Regional Air Quality

Planning Agency for the Maricopa area. The regional air quality plans are prepared through a

coordinated effort with the Arizona Department of Environmental Quality, Arizona Department of

Transportation, Maricopa County Air Quality Department, and Maricopa Association of

Governments. Over time, significant progress has been made to improve air quality due to the

implementation of the aggressive measures in the MAG regional air quality plans by the State and

local governments.

The MAG region has met the federal air quality standard for carbon monoxide. There have been

no violations of the carbon monoxide standard since 1996. The Environmental Protection Agency

redesignated the Maricopa nonattainment area to attainment for carbon monoxide on April 8, 2005.

EPA also approved the MAG Carbon Monoxide Redesignation Request and Maintenance Plan,

which demonstrated that the standard would be maintained through 2015.

The MAG region has met the federal air quality standard for one-hour ozone. There have been no

violations of the one-hour ozone standard since 1996. EPA redesignated the Maricopa

nonattainment area to attainment on June 14, 2005. EPA also approved the MAG One-Hour Ozone

Redesignation Request and Maintenance Plan, which demonstrated that the standard would be

maintained through 2015.

The MAG region has met the federal air quality standard for the 1997 eight-hour ozone standard of

0.08 parts per million. There have been no violations of the 1997 standard since 2004. On April

12, 2012, EPA published a proposed rule to approve the MAG 2007 Eight-Hour Ozone Plan.

Regarding the newly implemented, stricter ozone standard of 0.075 parts per million, the region had

only one monitor that violated the standard in 2011. 

The MAG region meets the fine particulate standard for PM-2.5.

Regarding PM-10, the Revised MAG 1999 Serious Area Particulate Plan for PM-10 was one of the

first in the nation and included 77 aggressive measures to reduce coarse particulate matter. On July

25, 2002, the Environmental Protection Agency approved the Revised MAG 1999 Serious Area

Particulate Plan for PM-10. The plan was heralded by EPA as one of the most comprehensive in

the country. Every city and town within the nonattainment area and Maricopa County have

implemented dust control measures to reduce PM-10. In addition, the MAG Regional Council has

allocated $24.9 million in Congestion Mitigation and Air Quality Improvement Funds over the last

12 years to purchase clean, dust-reducing street sweepers.

While the MAG 2007 Five Percent Plan for PM-10 was voluntarily withdrawn, the aggressive

measures in that plan continue to be implemented to reduce PM-10. In 2010, there were no
4

violations of the PM-10 standard.

Again, significant strides have been made to improve air quality in the MAG region. Air quality is

an important issue to the Maricopa Association of Governments. 

Comment: One of the issues that I wanted to raise this afternoon is this issue of three years of clean

data and the fact that you are looking at seeking to identify 21 of the 22 exceedances for 2011 as

exceptional events. I think by anyone’s common sense definition, when you start having that many

exceptional events, they fail to be exceptional, and we strongly question that.

Response: The EPA Exceptional Event Rule (EER) became effective on May 21, 2007. The EER

allows the ambient air quality data which is submitted to EPA and used in making regulatory

decisions, to be flagged and, where appropriate, excluded from calculations in determining whether

or not an area has attained the standard. The data flagged as “exceptional” must have been affected

by an exceptional event, which is defined as an event that affects air quality; is not reasonably

controllable or preventable; is an event caused by human activity that is unlikely to recur at a

particular location or a natural event; and is determined by the EPA in accordance with 40CFR 50.14

to be an exceptional event. 

In order for PM-10 monitoring data on an exceedance day to be excluded from the attainment

calculations for the nonattainment area, ADEQ must prepare documentation that meets requirements

of the EER and receives approval from EPA. For the Maricopa County PM-10 nonattainment area,

exceptional events are generally caused by high winds. In 2010, there was only one exceedance of

the PM-10 standard at one monitor in the nonattainment area, which did not occur on a windy day.

In 2011, the PM-10 standard was exceeded on 21 of 22 days during either strong frontal system

winds or summer monsoon thunderstorm outflows. The summer thunderstorm outflows produced

dust storms (haboobs) that were so unusual that they received national media attention (e.g., July

5, 2011). ADEQ is in the process of preparing documentation that meets EER requirements and

justifies that the 21 exceedances were unavoidable due to the uncontrollable meteorological

conditions that occurred during 2011.

Additionally, while crafting the EER, EPA acknowledged that natural events like high winds need

not be rare in order to qualify as an exceptional event, “It is important to note that natural events,

which are one form of exceptional events according to this definition, may recur, sometimes

frequently (e.g. western wildfires)” (72 FR 13563). The fact that 2011 had an unusually high

amount of dust storms does not preclude those dust storms from being considered as exceptional

events under the current definition of exceptional events in EPA’s EER.

Comment: The other thing is this plan is supposed to demonstrate best available control measures

and maximum measures as well and we didn’t see where you had demonstrated that in the plan.

And so, I would love for someone to point that out, but I believe you have to demonstrate in the plan

as well.
5

Response: The MAG 2012 Five Percent Plan for PM-10 is designed to meet the requirements in

Section 189(d) of the Clean Air Act. Section 189(d) indicates that “In the case of a Serious PM-10

nonattainment area in which the PM-10 standard is not attained by the applicable attainment date,

the State in which such area is located shall, after notice and opportunity for public comment, submit

within 12 months after the applicable attainment date, plan revisions which provide for attainment

of the PM-10 air quality standard and, from the date of submission until attainment, for an annual

reduction in PM-10 or PM-10 precursor emissions within the area of not less than 5 percent of the

amount of such emissions as reported in the most recent inventory for such area.”

The Best Available Control Measure (BACM) and Most Stringent Measure (MSM) demonstrations

are required under Section 189(b)(1) and 188(e) of the Clean Air Act. The MAG 2012 Five Percent

Plan for PM-10 includes control measures above and beyond the measures in the Revised MAG

1999 Serious Area Plan for PM-10, which addressed the BACM/MSM requirements.

On July 25, 2002, the Environmental Protection Agency approved the Revised MAG 1999 Serious

Area Plan for PM-10 that included the BACM/MSM demonstrations. On August 14, 2008, EPA

again took final action to approve the Best Available Control Measure and the Most Stringent

Measure demonstrations in the Revised MAG 1999 Serious Area Plan for PM-10 for the Maricopa

County Nonattainment Area (see 73 FR 47542).

Comment: One thing we have raised before, and it just doesn’t make a whole lot of sense - from just

when you think about a contingency measure. How can it be a contingency measure if it’s already

implemented? Contingency measures are supposed to be for, you know, if something else doesn’t

work, you have a contingency. And what has happened with a lot of previous measures is, we are

implementing a contingency and then there is no contingency, right, there is nothing left. And so,

we would like to have you take a look at that as well.

Response: Section 172(c)(9) of the Clean Air Act requires that nonattainment plans contain

contingency measures. Such measures are to be undertaken without further action by the State or

the EPA Administrator if the area fails to make reasonable further progress or meet the standard by

the attainment date. EPA encourages early implementation of contingency measures to reduce

emissions as expeditiously as practicable. (See EPA, Early Implementation of Contingency

Measures for Ozone and Carbon Monoxide (CO) Nonattainment Areas, August 13, 1993.) 

The contingency requirement is met in the MAG 2012 Five Percent Plan by quantifying the benefits

of PM-10 reduction projects that were implemented early (i.e., in 2008-2011). These projects

included PM-10 certified street sweeping of freeways and arterials; paving and stabilizing unpaved

roads, alleys and shoulders; reducing speed limits on unpaved roads and alleys; and overlaying state

highways with rubberized asphalt. It is important to note that there were many other measures in

the MAG 2007 Five Percent Plan that have been implemented, for which no credit is taken in the

MAG 2012 Five Percent Plan. These additional measures will also assist the area in demonstrating

attainment at all monitors by 2012.

Comment: Finally, we just continue to have concerns about enforcement and I think the gentleman
6

before me raised some of the issues with that and I know that there have been changes relative to

the BMPs for agriculture, but I still think there are good questions about whether those are truly

enforceable and would like to see more information in the plan on that as well.

Response: The Arizona Department of Environmental Quality (ADEQ) is responsible for

controlling dust emissions from agricultural activities in Area A, which includes the Maricopa

County PM-10 nonattainment area. Under Senate Bill 1552, passed by the Arizona Legislature in

2007, farmers are required to implement two best management practices (BMPs) to reduce PM-10

emissions in each of the following categories: tillage and harvest, non-cropland, and cropland.

Additional information on agricultural BMPs is available at

http://www.azdeq.gov/environ/air/plan/download/webguide.pdf. For more information on

enforcement of agricultural BMPs, contact Emily Bonnani at ADEQ, (602) 771-2324.

COMMENTS FROM THE ARIZONA CENTER FOR LAW IN THE PUBLIC INTEREST (Letter

from Joy E. Herr-Cardillo dated April 12, 2012)

1. BACM and MSM

Comment: As a serious nonattainment area for PM-10, the Phoenix area plan must include BACM

for all significant sources of PM-10 and PM-10 precursors. BACM, best available control measures,

are the maximum degree of emissions reductions possible after considering technical and economic

feasibility and environmental impacts of the control. These must be implemented independent of

attainment requirements. Also, because Phoenix obtained a five year extension of its attainment

deadline, its plan must include MSM (most stringent measures). In the General Preamble (59 FR

41998), EPA sets forth a multi-step process for identifying BACM/BACT for serious areas. The

proposed 5% plan does not include a BACM or MSM demonstration that follows this process,

therefore, it is initially difficult to even determine whether the plan satisfies the BACM/MSM

requirement. The state cannot rely upon the BACM/MSM demonstrations in the 1999 Serious Area

SIP, as that demonstration was prepared more than ten years ago, and, as the EPA recognized in its

proposed disapproval of the 2007 Draft 5% Plan, control measures that previously satisfied the

BACM requirement, may no longer represent the “best available” control measure. See, 75 FR

54806, 54812. Therefore, an updated BACM/MSM analysis should be included in the 5% plan.

Response: The MAG 2012 Five Percent Plan for PM-10 is designed to meet the requirements in

Section 189(d) of the Clean Air Act. Section 189(d) indicates that “In the case of a Serious PM-10

nonattainment area in which the PM-10 standard is not attained by the applicable attainment date,

the State in which such area is located shall, after notice and opportunity for public comment, submit

within 12 months after the applicable attainment date, plan revisions which provide for attainment

of the PM-10 air quality standard and, from the date of submission until attainment, for an annual

reduction in PM-10 or PM-10 precursor emissions within the area of not less than 5 percent of the

amount of such emissions as reported in the most recent inventory for such area.”

The Best Available Control Measure (BACM) and Most Stringent Measure (MSM) demonstrations

are required under Section 189(b)(1) and 188(e) of the Clean Air Act. The MAG 2012 Five Percent
7

Plan for PM-10 includes control measures above and beyond the measures in the Revised MAG

1999 Serious Area Plan for PM-10, which addressed the BACM/MSM requirements.

On July 25, 2002, the Environmental Protection Agency approved the Revised MAG 1999 Serious

Area Plan for PM-10 that included the BACM/MSM demonstrations. On August 14, 2008, EPA

again took final action to approve the Best Available Control Measure and the Most Stringent

Measure demonstrations in the Revised MAG 1999 Serious Area Plan for PM-10 for the Maricopa

County Nonattainment Area (see 73 FR 47542).

2. 2008 PM-10 Emissions Inventory

Comment: In its proposed disapproval of the 2007 Draft 5% Plan, EPA found that the 2005

emissions inventory relied upon by the state to be insufficiently accurate because it overestimated

the baseline emissions for construction and other sources. See 75 FR 54808. In the current plan,

MAG is relying upon a 2008 periodic emissions inventory which, like the 2005 inventory, was

prepared by Maricopa County Air Quality Department. At first glance, this more recent inventory

appears to address EPA’s concerns as it shows emissions from residential construction to be a

smaller percentage of the overall emissions. However, a comparison of the two inventories (and the

two draft plans) reveals a discrepancy that MAG does no appear to either acknowledge or explain,

and that is drastic reductions in the estimated emissions overall. In the 2005 inventory, total PM-10

emissions in the nonattainment area were calculated to be 84,753 tons per year. The 2008 inventory

puts that total at 48,148 tons per year - a reduction of more than 40% in just three years. It seems

highly unlikely that the area achieved such a reduction in emissions by the implementation of control

measures. As noted above, we did not see anywhere in the plan where this huge disparity in the data

was acknowledged or explained. This oversight should be addressed,. Also, because the inventory

is the principal basis for calculating the 5% annual reduction required under the CAA, it is important

to the public health that the amount of current emissions are not understated.

Response: The 2008 PM-10 Periodic Emissions Inventory for the Maricopa County, Arizona,

Nonattainment Area was revised by the Maricopa County Air Quality Department (MCAQD) to

address EPA concerns about the 2005 PM-10 Periodic Emission Inventory (PEI) expressed in the

proposed partial approval and disapproval of the MAG 2007 Five Percent Plan published by EPA

on September 9, 2010. (See 75 FR 54808.) MCAQD and EPA staff worked together to revise the

2008 PEI finalized in June 2011. In accordance with EPA guidance, MAG used the revised 2008

PEI as the basis for developing 2007-2012 emissions for the Draft MAG 2012 Five Percent Plan.

Ninety-two percent of the reduction in total PM-10 emissions from 84,753 tons per year in the 2005

PEI to 48,148 tons per year in the revised 2008 PEI can be attributed to four factors: (1) a decrease

in the number of acres permitted for construction activities and increases in compliance with

Maricopa County Rule 310, (2) a reduction in the material burned by wild fires, (3) annual variations

in meteorological data and use of a new and improved methodology to estimate windblown dust

emissions, and (4) decreases in PM-10 emissions from paved roads due to application of a new AP42 equation released by EPA in January 2011. Each of these factors is discussed in more detail
8

below. 

 

(1) One reason for the reduction in PM-10 emissions between 2005 and 2008 is the significant

decline in construction activity that took place during that period. In 2005, MCAQD issued

construction permits for 68,664 acres in Maricopa County; in 2008, this number was reduced to

42,130 acres, a 39 percent decline in three years. 

In addition, to address EPA concerns (in 75 FR 54808) regarding potential overestimation of PM-10

emissions from construction activities, MCAQD staff worked closely with EPA to improve the

methodology used to quantify rule effectiveness (i.e., compliance with Maricopa County dust control

rules). (See Appendix 3 of the revised 2008 PEI contained in Appendix A, Exhibit 1 of the Draft

MAG 2012 Five Percent Plan.) The new methodology developed in concert with EPA is used in

the revised 2008 PEI, as well as the Draft MAG 2012 Five Percent Plan, to estimate rule

effectiveness for Rule 310 (Fugitive Dust from Dust-Generating Operations), Rule 301.01 (Fugitive

Dust from Non-Traditional Sources of Fugitive Dust), and Rule 316 (Nonmetallic Mineral

Processing). Table 5-1 in the Draft MAG 2012 Five Percent Plan shows the new rule effectiveness

rates that were calculated for 2007 through 2010 using the new methodology and actual compliance

data. The rule effectiveness rate for construction activities in the 2005 PEI was 51 percent; using

the new methodology, the rule effectiveness rate for construction activities in the 2008 PEI is 90

percent. This represents a 76 percent increase in compliance with Rule 310 between 2005 and 2008.

Due to the 39 percent reduction in construction activity and 76 percent increase in rule effectiveness,

the PM-10 emissions from construction activities in 2005, 32,130 tons, declines to 7,964 tons in

2008, a 75 percent reduction. This reduction of 24,166 tons per year represents the largest

proportion (66 percent) of the decrease in total PM-10 emissions (36,605 tons) between 2005 and

2008. 

(2) In the 2005 PEI, wild fires produced 4,860 tons of PM-10 emissions based on 345,909 tons of

material burned within the nonattainment area. In the 2008 PEI, the comparable values for wild fires

are 424 tons of PM-10 emissions based on 33,479 tons of material burned. Due to the significant

reduction in material burned in the nonattainment area between 2005 and 2008, the PM-10 emissions

for wild fires are 91 percent lower in the 2008 PEI. This reduction of 4,436 tons explains another

12 percent of the decrease in total PM-10 emissions between 2005 and 2008.

(3) Windblown dust PM-10 emissions in the 2005 PEI are 7,380 tons for the nonattainment area,

compared with 4,815 tons in the 2008 PEI. MCAQD contracted with ENVIRON to estimate

windblown dust emissions for the 2005 PEI. ENVIRON applied the windblown dust emissions

model developed by the Western Regional Air Partnership (WRAP) to 2004 land use and 2005

meteorological data for Maricopa County. The ENVIRON methodology is documented in Appendix

3.2 of the 2005 PEI. 

For the revised 2008 PEI, MAG developed a new PM-10 emissions estimation methodology using

the latest scientific research on windblown dust in the arid southwest. (See Appendix 4 of the

revised 2008 PEI contained in Appendix A, Exhibit 1 of the Draft MAG 2012 Five Percent Plan.)
9

The methodology uses local data from observed windblown dust events, combined with empirical

data from wind tunnel studies performed in the deserts of the southwest. The windblown dust

estimates in the 2008 PEI are based on 2008 wind speed and precipitation data from 34

meteorological stations and the most recent land use data (2009) available for the nonattainment

area. The new methodology produces a more accurate estimate of the contribution of windblown

dust to the 2008 PEI. 

The 35 percent reduction in PM-10 emissions from windblown dust between 2005 and 2008 can be

attributed to the use of different methodologies, as well as different land use and meteorological data

for these years. The 2,565 ton reduction in 2008 represents seven percent of the decrease in total

PM-10 emissions between 2005 and 2008.

(4) In January 2011, EPA released a new version of the AP-42 equation that estimates particulate

emissions from vehicles traveling on paved roads. The new equation is documented in EPA,

Emission Factor Documentation for AP-42, Section 13.2.1, Paved Roads, January 2011. The paved

road PM-10 emissions in the revised 2008 PEI were developed using this new equation. Application

of the previous AP-42 equation (November, 2006) for the 2005 PEI resulted in paved road PM-10

emissions of 13,783 tons for the nonattainment area; paved road emissions estimated with the new

AP-42 equation are 6,694 tons, a reduction of 51 percent in the 2008 PEI. 

The reduction in paved road PM-10 emissions of 7,089 tons in the 2008 PEI is partially offset by

increases in emissions from exhaust, tire wear, brake wear, and vehicles traveling on unpaved roads.

The exhaust, tire wear and brake wear emissions are 1,404 tons higher in 2008, due to use of the new

EPA MOVES2010a mobile source emissions model, rather than the EPA MOBILE6.2 model used

in the 2005 PEI. In the 2008 PEI, unpaved road PM-10 emissions are also 3,221 tons higher, due

to use of updated information collected on unpaved roads and alleys. Overall, PM-10 emissions

from all onroad mobile sources are reduced from 24,013 tons in the 2005 PEI to 21,549 tons in the

2008 PEI. This net decline of 2,464 tons represents seven percent of the decrease in total PM-10

emissions between 2005 and 2008.

The sum of the emission reductions discussed in (1) through (4) above is 33,631 tons, which

represents 92 percent of the total decrease in PM-10 emissions between 2005 and 2008. The

remaining eight percent reduction can be attributed to factors such as increased rule effectiveness

for Rules 310.01 and 316 and decreased industrial activity, due to the economic recession that

commenced in 2008. The factors described above (decline in construction activity, increased

compliance with Rule 310, reduced impact of wild fires, improved windblown dust methodology

using 2008 meteorological and 2009 land use data, and the new EPA paved road dust equation)

explain the reduced emissions in the 2008 PEI and reinforce the accuracy of the 2008 PM-10

emissions used as the basis for the Draft MAG 2012 Five Percent Plan. 

It is also important to note that the calculation of annual five percent reductions in the Draft MAG

2012 Five Percent Plan is based on 2007 base case emissions of 59,218 tons per year, which are 23

percent higher than the 2008 emissions of 48,148 tons per year in the revised 2008 PEI. (See Page

ES-2 and Table ES-1 in the Draft MAG 2012 Five Percent Plan.) Therefore, the five percent
10

reductions calculated in the Draft MAG 2012 Five Percent Plan are not understated. 

3. Reliance upon EPA’s Concurrence Regarding Exceedances Claimed As Exceptional

Events:

Comment: We are concerned that the attainment demonstration in the 2012 5% Plan, like the 2007

5% Plan, relies upon the concurrence by EPA regarding exceptional events. As the plan

acknowledges there were 7 exceedances in 2009 alone that must be treated as exceptional events in

order for the area to meet the extended attainment deadline. Further, although the 2011 data has not

yet been finalized, the initial data indicates that there [sic] once again a significant number of

exceedances over multiple days and multiple monitors. The likelihood of eliminating all of these

exceedances as exceptional events would appear both remote and contrary to the public interest.

Therefore, we believe that a plan that proposes to achieve “attainment” simply by whitewashing over

severely unhealthful conditions is both irresponsible and contrary to the public interest. 

Response: Section 319(b)(2) of the Clean Air Act required EPA to publish and finalize regulations

governing the review and handling of air quality monitoring data influenced by exceptional events.

In establishing the requirement, Congress provided EPA with a definition of exceptional event that

recognized that not all episodes of air pollution can be controlled or prevented by means of

implementing the Clean Air Act. Specifically, Section 319(a)(1)(A) defined the term exceptional

event to include, among other things, those events that are not “reasonably controllable or

preventable” or are “...an event caused by human activity that is unlikely to recur at a particular

location or a natural event”. 

On March 22, 2007, EPA adopted the Exceptional Events Rule, codified in Code of Federal

Regulations, Title 40, Parts 50 and 51. In the implementing rules, EPA allows States to request the

exclusion of data showing exceedances or violations of the national ambient air quality standard that

are directly the result of an exceptional event, provided the State submits a demonstration justifying

the exclusion of the data. All such demonstrations must undergo public comment prior to

submission for concurrence by EPA.

Section 110 of the Clean Air Act requires all State Implementation Plans (SIPs) to address

reasonably controllable sources of air pollution, as well as any reasonably controllable or

preventable activities. Through the development of the proposed 5% Plan, ADEQ, MAG and

MCAQD have evaluated the exceedances that occurred in 2009 and 2011, and have compared them

to the requirements in EPA’s Exceptional Events Rule, as well as EPA’s Draft 2011 Exceptional

Events Guidance document. Based upon that analysis it was concluded that the overwhelming

majority of exceedances that occurred during 2009 and 2011 were the direct result of events that

could not be prevented or that overwhelmed the controls required by the existing non-attainment

area plans. 

On March 14, 2012, after 30 days of public comment and in accordance with EPA’s Exceptional

Event Rule and Draft 2011 Exceptional Events Guidance document ADEQ submitted to EPA
11

documentation demonstrating that the PM-10 exceedances recorded between July 2 and July 8,

2011, were the result of exceptional events that were not preventable or were beyond any reasonable

control. EPA’s decision regarding this documentation is expected by July 2012. Based on the

submitted analysis, the similarity of other 2011 exceedances to those observed between July 2

through 8, and a review of the likelihood of EPA concurrence under both the Exceptional Events

Rule and the Draft 2011 Exceptional Events Guidance, ADEQ, MCAQD, and MAG have concluded

that there is a relatively low risk of nonconcurrence.

Finally, recognizing that the public is still exposed to these high concentrations of PM-10, regardless

if they are reasonably preventable or controllable, ADEQ is required by Arizona Revised Statute §

49-424(11) to develop and disseminate air quality dust forecasts for the Maricopa County PM-10

nonattainment area. These forecasts are required to identify the risk of dust generation for the next

five consecutive days, and must be posted, at a minimum, on ADEQ’s web site, five days each week.

In addition to the dust forecasts, ADEQ also publishes a forecast that predicts the air quality index

for the upcoming days, and issues health watches or high pollution advisories on days where

exceedances of the PM-10 standard are expected to occur. ADEQ has taken the additional step of

making these forecasts available to any interested party via electronic mail. To sign up for these or

other ADEQ issued forecasts, please visit

https://public.govdelivery.com/accounts/AZDEQ/subscriber/new. 

4. General Permit BMPs and Agricultural Permit BMPs:

Comment: While we generally support the adoption of the general permit requirement for all dust

generating activities and the increased stringency of the agricultural permit requirements, the plan

does not adequately demonstrate that either of these control measures satisfy the BACM and MSM

requirement. The plan did not mention the concerns raised by EPA in its proposed rulemaking in

2010 regarding the agricultural BMPs or indicate whether or how these concerns have been

addressed.

Response: As part of the stakeholder process for this revision to the State Implementation Plan,

ADEQ, MCAQD and MAG analyzed the conditions under which Maricopa County’s PM-10

exceedances occurred. Since 2007, the most common factor associated with PM-10 exceedances

in Maricopa County was elevated wind speed. In reviewing other PM-10 control programs, ADEQ,

MCAQD and MAG were unable to identify another comprehensive SIP program that was

specifically designed to control dust on days with high winds. As a result, a new, innovative method

for controlling dust was required.

ADEQ agreed to legislation that requires the Department to issue a pollution forecast that identifies

the risk of dust generation on subsequent days. Based upon ADEQ’s forecast, all owners or

operators of dust generating activities within Maricopa County are required to implement air

pollution controls as soon as practicable before and during a day forecast to be at high risk of dust

generation. Those owners and operators that already have an air quality permit are required to

continue complying with the conditions of their permit on those days. If the owner or operator of
12

the dust generating activity did not require an air quality permit, ADEQ was given the authority to

require these owners or operators to obtain a Dust Action General Permit. The controls that were

included in the Dust Action General Permit build upon the existing Best Available Control Measure

(BACM) requirements of MCAQD Rule 310 that was approved into the Arizona State

Implementation Plan on July 25, 2002 (at 67 FR 48716). In addition to these controls, the permit

also adds additional monitoring, record keeping and reporting requirements that enhance the

enforceability of these control measures. Because there is no other program in the Country that is

similar to the Dust Action General Permit, the control measure is being submitted in accordance

with EPA’s September 2004 guidance entitled Incorporating Emerging and Voluntary Measures

in a State Implementation Plan (SIP), and there are no benchmarks for it. 

This plan is being submitted pursuant to Clean Air Act § 189(d) which provides for annual emission

reductions of 5% until attainment is demonstrated. This plan includes a commitment to evaluate the

effectiveness of MCAQD Rule 310.01 in calendar year 2013. If the evaluation does not result in

sufficient emissions reductions, ADEQ has committed to submitting a SIP revision that contains

replacement measures to reduce PM10 emissions by an amount equal to or more than the total PM10

emissions reductions that were not achieved by these measures. 

With respect to the Agricultural Best Management Practices (Ag BMP) program, portions of the

current program have already been approved into the SIP and those commitments remain on-going.

This Section 189 plan did not rely on any improvements to the previously approved Ag BMP

program to achieve the required annual 5% emissions reductions or to demonstrate that the plan

results in attainment. As a result, the improvements that were made to the program in 2007, 2009,

2010 and in 2011, have not been included as part of this SIP revision.

In 2009 and 2010, the statutes authorizing the Ag BMP program have changed such that after June

1, 2009, this program automatically becomes effective in all areas that are re-designated as moderate

or serious nonattainment for PM-10. Operations subject to the program in areas that are redesignated as moderate nonattainment are required to apply at least one BMP in each applicable

category, whereas operations in areas that are re-designated as serious nonattainment are required

to apply at least two BMPs in each applicable category. Because of the statewide applicability of

this program, the Arizona Department of Environmental Quality will submit the program as a

separate, independent revision to the State Implementation Plan.

5. Enforceability of Control Measures:

Comment: We have concerns about the enforceability of control measures in the plan. As you

know, citizen enforcement is encouraged under the Clean Air Act. However, in recent years, when

citizens have brought actions to enforce control measures that the state is responsible for

implementing, the state has invoked the Eleventh Amendment in an effort to avoid the enforcement

of its obligation to comply with the SIP. See Paisley v. Brewer, CV2:10-cv-01253-DGC (D.Ariz.)

and Sweat v. Hull, 200 F. Supp. 2d. 1162 (D. Ariz. 2001). Although the defense did not preclude

injunctive relief in either case, it unnecessarily protracted the litigation and demonstrated the lack
13

of commitment on the part of the state to fulfilling its obligation under the SIP. Therefore, we

believe that where the state or one of its subdivisions (i.e., a county) assumes responsibility for the

implementation of specific control measures, the commitment should include an unequivocal

consent to federal jurisdiction if enforcement is sought under the citizen suit provision. This consent

will ensure that the measures are fully enforceable by both EPA and affected citizens, as the

enforcement scheme adopted by the Act contemplates.

Response: As noted in the comment, the legal strategy employed by Arizona did not preclude

injunctive relief and it did not affect the enforceability of the SIP by either EPA or affected citizens.

Because the merits of each lawsuit must be reviewed on a case-by-case basis, the response to the

lawsuit must address the merits of each case, and the defense strategy in question did not affect the

enforceability of the SIP, it is not prudent to unnecessarily limit future defense strategies.

6. Technical Issues and Concerns:

GENERAL

Editorial Comments:

Comment:

• The report provides very limited examples and few calculations to support the reported

values. 

• The report is also lacking equations to support reported values. 

• The reported values are in a variety of units, which makes comparisons difficult.

Response: The technical analyses conducted to support the attainment demonstration in the Draft

MAG 2012 Five Percent Plan for PM-10 were performed by MAG, with assistance from Sierra

Research. Some of the calculations and equations used to perform the rollback modeling for the

attainment demonstration were too voluminous to be included in the Draft Plan. However, all of the

technical assumptions, equations and reported values documented in the Draft MAG 2012 Five

Percent Plan have been reviewed by and received concurrence from EPA and other members of the

5% PM-10 Plan Technical Committee. 

The 5% PM-10 Plan Technical Committee was formed by the Arizona Department of Environmental

Quality (ADEQ) in response to a stakeholder meeting conducted on February 8, 2011. The meeting

was held to discuss the withdrawal of the MAG 2007 Five Percent Plan for PM10 for the Maricopa

County Nonattainment Area and to allow EPA to directly discuss what portions of the 5% Plan

required additional work in order to be considered an approvable plan. During the meeting it was

determined that a technical workgroup comprised of members from ADEQ, the Maricopa County

Air Quality Department, the Maricopa Association of Governments and the U.S. EPA would be

formed to meet on Wednesday of every other week. The first meeting of the 5% PM-10 Plan

Technical Committee occurred on February 9, 2011.
14

The stated mission and purpose of the Maricopa 5% PM-10 Plan Technical Committee was to

provide technical work to support a SIP submission to EPA by January 2012; investigate and resolve

stated plan deficiencies and support improvements in emission inventories, exceptional event

documentation and conceptual model of air quality problem/control measures.

The 5% PM-10 Plan Technical Committee met more than twenty times to review technical work

related to the revised 2008 PM-10 emissions inventory, exceptional events documentation, the Dust

Action General Permit, and the modeling assumptions and protocol for the Draft MAG 2012 Five

Percent Plan. The Technical Support Document for the Draft Plan describes the Committeeendorsed modeling methodology that demonstrates attainment of the PM-10 standard in 2012.

MODELING

Model Selection:

Comment:

• The air quality modeling demonstration for the 24-hour PM10 standard is based on U.S.

EPA’s rollback modeling method. Federal regulations state that “all applications of air

quality modeling involved in this subpart shall be based on the applicable models, data

bases, and other requirements specified in appendix W of this part (Guideline on Air Quality

Models).” 40 CFR Part 51.160(f).

• Appendix W section 5.2.2.2 PM10; “Refined models such as those discussed in subsection

4.2.2 are recommended for PM-10.”

• Appendix W Section 4.2.2(b) Refined Analytical Techniques: “For a wide range of

regulatory applications in all types of terrain, the recommended model is AERMOD.”

• Appendix W Section 5.2.2.2(e): “Due to the difficult nature of characterizing and modeling

fugitive dust and fugitive emissions, it is recommended that the proposed procedure be

cleared by the Regional Office for each specific situation before the modeling exercise is

begun.”

• The rollback approach is not one of U.S. EPA’s preferred methods for demonstrating

attainment of the PM10 NAAQS

Response: Use of distance-weighted rollback was cleared by staff from EPA Region IX before the

modeling exercise for the Draft MAG 2012 Five Percent Plan began. As discussed in the previous

response to the editorial comments, EPA was an active member in the 5% PM-10 Plan Technical

Committee and reviewed all of the technical assumptions and methods to be used prior to the

commencement of attainment modeling for the draft Plan. 
15

In an August 5, 2011 e-mail from Greg Nudd, EPA, to the 5% PM-10 Plan Technical Committee,

Scott Bohning, EPA, provided the following comments on the Draft Conceptual Model for

Demonstrating PM-10 Attainment document, July 25, 2011: “The chosen distance-weighted rollback

seems like a good approach. It gets the main benefit of dispersion modeling over simple rollback in

that it accounts for source distance from the monitor, but with less work and without the misleading

precision that can accompany dispersion modeling of fugitive dust. Back-trajectories along with

judgement based on available wind speed and direction measurements are a reasonable basis for

choosing the emission inventory domain.” 

Although AERMOD was used to model attainment in the MAG 2007 Five Percent Plan for PM-10,

EPA’s preferred model for demonstrating attainment in the replacement 2012 Plan is distanceweighted rollback, rather than AERMOD. In addition to model selection, EPA provided other

technical recommendations that are reflected in the attainment modeling described in Chapter V of

the Technical Support Document in Appendix B, Exhibit 1 of the Draft MAG 2012 Five Percent Plan.

Weighted Rollback:

Comment: The report does not present any of the rollback questions used so it is unclear which

rollback method was used.

Response: The calculations made using the rollback model are better understood through stepwise

text descriptions rather than by a single or set of equations. The steps used in the weighted rollback

model used in the 2012 Five Percent Plan are described as follows:

1. Determine the hourly concentrations recorded at the designated monitoring station on the

design day.

2. Parse the hourly concentrations into high wind and low wind bins.

3. Determine the background PM10 concentration for the design day.

High Wind Hours (Baseline Year):

4. Plot hourly back-trajectories for each high wind hour using the 5-minute meteorological data

recorded at the designated monitoring station.

5. From a GIS land use database, extract the land use designations and coordinates of each 10-

acre grid cell within 1 mile laterally of the back-trajectory path.

6. For each 5-minute segment of a high wind hour, use the average measured windspeed to

calculate the emissions for each of 11 land use classes and 2 disturbance states (disturbed

and undisturbed) and then sum the 5-minute contributions to derive an hourly emission rate

for each land use and disturbance state.
16

7. For each 10-acre grid cell, apply the appropriate hourly emission rate and then divide by the

distance in feet between the grid cell and the monitor to calculate the distance-weighted

emission rate for that parcel.

8. Sum over all of the 10-acre grid cells in the hourly modeling domain to compute total

distance-weighted emissions for that hour and domain.

High Wind Hours (Attainment Year):

9. Apply the appropriate reduction factor by land use and disturbance state to the emissions

from each 10-acre grid cell. Divide the resulting emissions by the distance to the monitor

to calculate the attainment year distance-weighted emissions for each grid cell.

10. Sum over of the 10-acre grid cells to compute total distance-weighted emissions for that hour

and domain.

High Wind Hour Reduction Factor:

11. Divide each hour’s Attainment Year total distance-weighed emissions by the appropriate

baseline year total distance-weighted emissions and subtract these fractions from one to

compute the high wind hourly reduction factors.

12. Compute the attainment year high wind hour PM10 concentration at the monitor by

subtracting the background concentration from the baseline year high wind hour

concentration, multiply this result by the appropriate high wind hour reduction factor, and

add this result to the background concentration.

Low Wind Hours (Baseline Year):

13. Compute annual ton/acre PM10 emission rates by dividing nonattainment area-wide land usespecific annual emissions by total acres devoted to that land use to derive annual ton/acre

emission rates by land use.

14. Extract total acres per land use within the low wind modeling domain from a GIS land use

database.

15. Multiply total acres per land use by the appropriate annual emission rate to derive total

annual emissions per land use type in the low wind modeling domain. Sum over all land

uses to derive total annual baseline emissions within the low wind modeling domain.

Low Wind Hours (Attainment Year):
17

16. Apply land use-specific reduction factors to appropriate annual baseline emissions by land

use to derive total attainment year emissions by land use category in the low wind modeling

domain. Sum over all land uses to compute total annual attainment year emissions with the

low wind modeling domain.

Low Wind Hour Reduction Factor:

17. Divide the annual attainment year domain-wide emissions by the annual baseline year

domain-wide emissions and subtract from one to determine the low wind hour reduction

factor.

18. Compute the attainment low wind hour PM10 concentration at the monitor by subtracting

the background concentration from the baseline year low wind hour concentration, multiply

this result by the appropriate low wind hour reduction factor, and add this result to the

background concentration.

Design Day Attainment Year PM10 Concentration:

19. Sum over all high and low wind hourly attainment year PM10 concentrations to determine

the attainment year 24-hour PM10 concentration for the design day.

The basic equations for high wind and low wind hour PM10 concentrations are:

For a high wind hour: Cfuture = ((Cbaseline – Cbackground) * (1 – HWreduction)) + Cbackground

For a low wind hour: Cfuture = ((Cbaseline – Cbackground) * (1 – LWreduction)) + Cbackground

where: C = PM10 concentration, ug/m3

 HW = percent high wind reduction,

LW = percent low wind reduction.

This methodology is described in more detail on p. V-62 to V-78 in Appendix B, Exhibit 1.

Comment: If the analysis is based on the modified rollback method, was a spatial distribution

analysis performed?

Response: A spatial analysis was performed when the reductions in distance-weighted emissions

were evaluated for high wind hours on the June 6, 2007 design day. For each high wind hour, backtrajectories were plotted, and emissions per grid cell in the back-trajectory modeling domain were

calculated. Control factors applicable to individual land uses in the attainment year, 2012, were

applied to 2007 baseline emissions. Baseline and horizon year emissions for each grid cell were

adjusted by the distance-related weighting factor and then summed over the entire back-trajectory

to arrive at total distance-weighted emissions. The overall fractional reductions in emissions were
1

 Rollback Modeling Basic and Modified, Air Waste Management Association 25:9 (September 1975)

18

calculated for each high wind hour, and the results were presented in Table V-31 of Appendix B,

Exhibit 1.

The results in percent reduction of weighted emissions shown in this table for each high wind hour

cluster remarkably closely. During the June 6th design day, wind directions measured at the West

43rd Avenue station varied from 220° to 255°, resulting in corresponding variations in fractional land

uses between each hourly back-trajectory. Regardless of these differences, the resulting fractional

reductions in weighted emissions varied by less than 12%, from a low of 33.2% to a high of 37.1%.

This result demonstrates that reductions in concentrations measured at the monitoring station are

relatively independent of wind azimuth – and accompanying emission source spatial distribution -

during high wind hours.

Comment: In appendices Volume 2 p. V-5, under the Weighted Rollback section, the report states:

“The reduction factor is calculated on the basis of the distance between each source and the

impacted monitoring site”

• Please provide the equation(s) used for the weighted rollback analysis. Based on the

statement above, it is not clear how MAG has calculated the emissions weighting. The

equations1

 used in EPA’s proportional or modified rollback method do not involve any

interactions among individual sources, only each individual source and a monitor.

Response: Please see the Response to the first Weighted Rollback Comment above.

Comment: Rollback typically requires speciated profiles of soil dust from ambient measurements

and chemical analysis for source apportionment calculations, using CMB (Chemical Mass Balance).

Did MAG use any source profiles to support the modeling analysis? Please refer to “Guidelines to

Sampling and Analysis Applicable to Receptor Modeling”

Response: The first sentence of the referenced report states “Chemical characterization of

suspended particles is necessary, along with the application of receptor models to apportion ambient

concentrations to their sources for the development of emission reduction strategies.” The methods

outlined in the report are designed to guide the collection and chemical characterization of ambient

aerosol samples. The role of CMB is to then establish the relative contribution of sources with

known unique chemical signatures to the ambient samples collected in the field. Under high wind

conditions, the dominant PM-10 emission source is fugitive dust. Unfortunately, there are no

chemical signatures available to characterize fugitive dust from different land uses within the

nonattainment area. Without this information, it is not possible for the rollback methodology to use

CMB to address source apportionment. 

Comment: MAG 2012 FIVE PERCENT PLAN FOR PM-10 FOR THE MARICOPA COUNTY

NONATTAINMENT AREA. P. 6-44: “ The attainment modeling for the nonattainment area

demonstrates that the 24-hour PM-10 standard will be met by a relatively narrow margin in 2012
19

(i.e., 153.8 ug/m3 at the West 43rd Avenue monitor).” Was a sensitivity analysis performed to

evaluate the degree of confidence in the results? A sensitivity analysis may reveal conditions where

the modeling fails or requires improvement, so as to ensure NAAQS are attainment according to the

plan.

Response: The dominance of near upwind sources on monitored concentrations during high wind

hours, as evidenced by the analysis conducted to determine the appropriate distance-weighting

factor, and the tight cluster of back-trajectory hour reduction factors presented in Tables V-25

through V-31, demonstrate the relative insensitivity of monitored PM10 concentrations to emission

source spatial distribution during high wind hours. The variability in source spatial distribution is

the greatest uncertainty with respect to determining locations of peak PM10 concentrations.

Distributions of meteorological parameters and soil surface emissions rates during high wind

conditions have been measured and better characterized than land use distributions. Thus, a

sensitivity analysis was conducted on the emission parameter possessing the greatest uncertainty,

and no further analysis is needed.

Comment: Rollback only works if the monitor is at the point of highest impact. Since air pollution

standards must be attained within the entire planning area and not simply at the monitors, how

confident is MAG in their choice to use a single point to represent the entire Maricopa County

nonattainment area? Dispersion modeling typically provides for a more credible product, since they

more realistically account for spatial and temporal patterns.

Response: The analysis of the temporary monitoring data shows that when winds exceeded 12 mph

and were coming from the dominant high wind direction (220° to 290°), the maximum

concentrations were always recorded at the West 43rd Avenue monitoring site. Additional analysis,

presented in Table V-19, demonstrates that the highest wind gusts in 2007 were recorded at the West

43rd Avenue monitor. Given the frequency and magnitude of exceedances at this site, it is

reasonable that it was selected and approved by EPA for one of the design day attainment

demonstrations (i.e., May 4th). However, to ensure that a single location does not bias the

attainment demonstration, a second high wind day was selected, one in which multiple monitors

exceeded the standard (i.e., June 6th) and attainment demonstrations were prepared for the six

monitoring sites in the nonattainment area with meteorological measurements. The use of rollback

to demonstrate attainment at six widely dispersed monitoring sites with varying back trajectories

capturing a variety of land uses, activity and emissions provides ample evidence that a single point

was not used to demonstrate attainment. The fact that EPA participated in the development of this

approach and ultimately approved it further demonstrates the validity of the methodology.

Comment: Is MAG confident that the receptor location in the high-wind micro inventory domain

is representative of worst case conditions? Are there any locations within the high-wind domain

where predicted concentrations can be potentially higher than the monitor site?

Response: The temporary monitoring study provides insight into concentrations recorded at

multiple locations between the West 43rd Avenue monitor and the edge of the desert (west of
20

Buckeye at the Arlington monitor), a distance of roughly 35 miles. The results of that study,

presented in V-7 – V-20, show that when winds exceeded 12 mph and were coming from the

dominant high wind direction (220° to 290°), the maximum concentrations were always recorded

at the West 43rd Avenue monitoring site. Empirically this data supports the conclusion that the

receptor location in the high-wind micro inventory is located at the worst case location. The fact

that attainment was demonstrated on June 6th at six widely dispersed monitoring sites adds further

confidence that the modeled domain represents worst case conditions.

Comment: According to the charts in Fig. V4 Appendix 2. ~98.6% of the total exceeding PM10

concentration originates from sources within 2km of the monitor. Under the current modeling

scenario, sand & gravel sources are by far the greatest contributor to PM10. Yet, the source sand

and gravel source category is also the source category with the greatest estimated improvement in

Rule Effectiveness. While nearly all of the vacant lots, agricultural sources and open areas are

beyond 2km from the W43rd monitor and contribute less than to 1.4% of their total potential

emissions to the monitor.

Response: It is incorrect to assume that sand and gravel land uses are by far the greatest contributor

to PM10 under the distance-weighted rollback modeling performed at the West 43rd Avenue

monitor. In fact, a close examination of the land uses nearest to the West 43rd Avenue monitor

within the high wind domains do not support that conclusion. The land uses nearest the monitor in

the high wind domains are industrial and commercial lots. Under the distance-weighted rollback

methodology, these high wind emissions have the highest weight. There are also vacant lots that are

closer to the monitor within the high wind domain than sand and gravel land uses. Also, open areas

of the Salt River that are not mined for sand and gravel (displayed as "wash" land use in Figure V-16

as an example) within the high wind domain are closer to the West 43rd Avenue monitor than active

sand and gravel operations. As such, these land uses contribute far more distance-weighted

emissions than 1.4% assumed by the commenter. 

Comment: So, the weighted emissions scenario for this model design favors an increase in Rule

Effectiveness of approximately 73%, from 40% yielding a net change of ~33%.

Response: Between 2007 and 2012, rule effectiveness for sand and gravel operations (Rule 316)

does increase from 40% to 73%. The impact of this increase directly impacts un-weighted emissions

and has an indirect effect on distance-weighted emissions, as distance to the modeled monitor has

a greater impact on distance-weighted emissions than increases in rule effectiveness in the land use

categories. 

Comment: A quick comparison with the average % Reduced of Weighted Emissions in Appendix

2. P. V – 68, Tables V-25 : V-36, provides a check of the assumptions. The average reduction

according to the current model design is very close to the net increase in Rule Effectiveness for sand

and gravel operations.
2

 AERMOD ADERMD Evaluations Under the Evaluations Under the 1-hour NO2 and SO2 NAAQS. 10th

Conference on Air Quality Modeling March 14, 2012; AERMOD Evaluation for Non-Guideline

Applications. 9th Conference on Air Quality Modeling October 9, 2008; AERMOD Latest Features and

Evaluation Results: U.S. EPA, 2003

21

Response: The average percent reduction in distance-weighted high wind emissions ranges from

26.9% to 35.6% in Tables V-25 through V-31 from a variety of monitors across the nonattainment

area, not just the monitor located at West 43rd Avenue. Many of the modeled high wind emissions

are from domains that have little to no sand and gravel land uses (e.g., Central Phoenix monitor,

Table V-26 or Higley monitor, Table V-29). The commenter's observation that the percent

reductions in high wind emissions is around the increase in rule effectiveness for sand and gravel

operations (33%) is merely a mathematical coincidence.

Comment: If a receptor is placed in the middle of the domain, where there are no sand and gravel

sources, will the emissions still work? What are the new impacts from vacant lots and other nearby

sources?

Response: As noted above, many of the modeled high wind emissions are from domains where sand

and gravel land use is limited or nonexistent. The increased rule effectiveness impacting these land

uses is clearly not required to demonstrate attainment within these domains. 

General Modeling:

Comment: There are a number of inaccuracies in Volume 2 p. V-5, Available Modeling Concepts.

Response: Without identification of the specific inaccuracies alleged, it is impossible to respond.

Comment: MAG’s assertion that AERMOD is less accurate than rollback models is baseless. There

are a number of model evaluation studies2 that test AERMOD against a variety of regulatory

scenarios. In the vast majority of cases, AERMOD provides an adequate level of conservatism for

NAAQS protection.

Response: The limitations of using AERMOD in high wind day attainment demonstrations are

discussed on p. V-5 and V-6 of Appendix 2, Exhibit 1.

Comment: MAG concludes that AERMOD model performance is poor for high winds. Yet, the

weighted rollback (1/d) method used in the 2012 5% plan attainment modeling is calculated from

AERMOD model results.

Response: AERMOD was used in the attainment demonstration to determine the appropriate width

of high wind hour modeling domains and to determine the appropriate form of the distanceweighting factor. These model runs used hypothetical source configurations typical of bare soil

areas predominately contributing to fugitive dust emissions on high wind hours. Further detail on

these analyses are provided on pp. V-21 to V-27 and V-55 to V-58.
22

Back Trajectory:

Comment: Appendix 2, V-55. Please provide a citation for the back trajectory equations?

• X=X1+WS*0.447*60*5*SIN(WD*2*PI/360)

• Y=Y1+WS*0.447*60*5*COS(WD*2*PI/360)

Response: The back trajectory equations are based on the wind direction and wind speed

measurements recorded at each monitoring site. The equations back calculate where the air parcel

would be based on these 2 variables in a 2_D wind field. The calculations begin with the ending 5-

minute values recorded each hour and calculate the location of where the air parcel was located at

the end of the previous 5-minute period, etc. A similar approach has been used in “Analysis of

Ozone in the Southeast Desert Air Basin on the Case Study Day of April 29, 1989, June 25, 1991.

Sierra Research Inc.”

Comment: It appears that the trajectories may actually be tangential streamlines and not parcel

trajectories. According to the equations above, X and Y are calculated for each hour of

meteorological data. This method creates a simplified representation path, because streamlines are

actually a series of straight line tangents to a path, in this case one tangent for each new hourly

record. Trajectories are based on motion equations are more representative of a true path.

Considering the “relatively narrow margin” of modeled attainment, MAG should perform additional

trajectory sensitivity analysis so that the most conservative domain size and source mix is selected

for modeling. 

Response: It is correct that X and Y represent the end point of tangential streamlines, however, they

are based on 5-minute measurements, not hourly measurements. It is important to note that the

weighted rollback methodology places a premium on the accuracy of the location of sources

producing nearby emissions relative to those located farther away. Thus, insight provided by 5-

minute measurements have much higher value than those provided by hourly values. The principle

difference between the air parcel-based method and the method used in the report is 3D versus 2D

(i.e., representation of vertical air movement). High wind conditions, however, are usually

characterized by elevated mixing layers and greater instability. Under these conditions, emissions

from upwind sources should be well mixed in the vertical structure, therefore, the gradient between

concentrations aloft and nearer the ground are not expected to be significant. Thus, the air parcelbased method and the one employed in this effort are expected to produce similar results if they

employ the same time step and employ a similar spatial representation.

With regard to investigating alternate domains and source mixes, the attainment demonstration

methodology has rendered domain size to be mute because emissions from nearby sources have

dramatically greater influence on monitored concentrations than emissions from sources located

farther upwind. A review of trajectories over nearby sources, however, shows that they vary

substantially as the high wind arc shifts within the southwest quadrant (roughly 220° to 260°).

Within this domain the share of passive open space drops by an order of magnitude as the arc shifts
23

toward the west. While this shift produces a large change in the land use distribution and the related

distance weighted emissions, there is little difference in the 2007 versus 2012 reductions observed

across any the high wind days. A review of Tables V-25 to V 31 shows little variance between

individual high wind hourly reductions and the overall daily mean reduction, despite the fact that

there are large differences in the hourly wind directions and land uses. Given the relatively tight

cluster of observed reductions there is no need to investigate the effect of alternate source mixes on

demonstrating attainment.

Comment: Did MAG consider using ensemble or matrix trajectories using NOAA’s HYSPLIT

model? The variation in trajectory start times and location could prove to be a valuable form of

sensitivity test for calculating domain size and source mix.

Response: Yes, we considered using HYSPLIT, but the following technical and accuracy concerns

led us to choose the method we used in the report.

1. HYSPLIT is structured to run on an hourly basis. Meteorological data is typically supplied

from hourly 3-D meteorological model (e.g., WRF, MM5, etc.) outputs. Readily available

meteorological models addressing the PM-10 nonattainment area are structured to represent

a relatively coarse hourly 12 km by 12 km grid domain. 

2. 5-minute wind speed and wind direction measurements are available from many of the

monitoring sites. These data provide the best representation of air movement impacting each

of these monitors. To use these data in HYSPLIT requires that they be assimilated into one

of the available meteorological models. 

3. Discussions with NOAA indicated the data need to be gridded into a specific format and the

preferred approach would be to use something like WRF-ARW. 

Our concern is that once the 5-minute data is entered into WRF or a similar model, it would be

modified to reflect the physical principals governing the operation of the model. Uncertainty about

the magnitude of these changes and the coarse size of the available grid structure were considered

relative to the demands of the weighted rollback methodology which places a premium on emissions

of nearby sources relative to those located farther away. We determined that more accurate

estimates of the location of nearby sources impacting the monitors would be produced by using unaltered 5-minute measurements in the back trajectory calculations and for that reason did not pursue

the use of HYSPLIT.

Comment: Are high wind back trajectories calculated for each monitor and event with high winds

in 2007? How about other years? Will 2008, 2009, 2010 and 2011 have a day that is more

conservative?

Response: High wind back trajectories were calculated for May 4th for the West 43rd Avenue

monitor (when it alone exceeded the standard) and on June 6th for six monitors (i.e., West 43rd
24

Avenue, Central Phoenix, Durango Complex, Greenwood, Higley, and West Phoenix) that collected

meteorological data (when both the West 43rd Avenue and Higley monitors exceeded the standard).

Since EPA accepted and approved the selection of these design days, there was no need to

investigate high wind conditions on other days or years. 

Emissions:

Comment: Appendix 2. P. V – 62 High Wind Inventories; Were emissions calculated based on wind

speeds from meteorological monitor, or wind speeds calculated at each back trajectory location?

Response: High wind emissions were calculated using the five-minute or hourly average wind

speeds as measured by the anemometer co-located at each modeled PM-10 monitor (i.e., West 43rd

Avenue, Higley, etc.).

Comment: Appendix 2. P. V – 67 “The calculated emissions for each land use parcel are divided

by the distance (feet) from the modeled monitor.” Please provide these calculations.

Response: As described on page V – 62, the maximum size of a land use parcel within the high

wind domain is 10 acres. Many of the parcels within the high wind domain are less than 10 acres,

as land use types and property boundaries change frequently within the high wind domain. Through

the use of GIS, the distance from each parcel within the high wind domain to the modeled monitor

is calculated. This distance can then be used to weight the high wind emissions of each parcel by

distance from the modeled monitor (i.e., emissions from land uses closest to the monitor are

weighted higher than land uses farther away from the monitor). There are thousands of individual

land uses parcels within each hourly high wind domain. It would be impractical to provide each

individual land use parcel distance-weighted calculation, for each modeled high wind hour (over

200,000 individual calculations). As such, the sum of un-weighted and distance-weighted emissions

for all land use parcels within each hourly high wind domain are provided in Tables V – 25 through

V – 31 (pages V – 68 through V – 73). 

Comment: Appendix 2. P. V – 68, Tables V – 25 : V – 36. It is very difficult to compare tons to

tons/feet (if at all). Please explain the units tons/feet. Are the tons/feet estimates the emissions

equivalent to the source receptor interaction coefficient (x/Q)? If so, please explain.

Response: In Tables V – 25 through V – 31 both un-weighted and distance weighted emissions are

provided for each modeled high wind hour. The unit of measure for un-weighted emissions is tons.

The descriptor of tons/feet in the distance-weighted column of tables V – 25 through V – 31 is

provided to remind the reader that these tons have been weighted by distance from the monitor (1/d),

as measured in feet. For example: If land use parcel X in the high wind domain has un-weighted

emissions of 100 tons, and is 1000 feet away from the monitor, its distance weighted emissions are

0.1. If land use parcel Y in the high wind domain has un-weighted emissions of 100 tons and is 2000

feet away from the monitor, its distance weighted emissions are 0.05. If there were only land use

parcels X and Y in a hypothetical high wind domain, total un-weighted emissions for that
25

hypothetical high wind domain would be 200 tons and distance-weighted emissions would be 0.15.

As such, Tables V – 25 through V – 31 provide the sum of un-weighted and distance-weighted

emissions for all land use parcels within each hourly high wind domain. (Note: Tables V – 32

through V – 36 do not discuss distance-weighted emissions (tons/feet) as incorrectly implied by the

comment.)

Comment: Appendix 2. P. V – 68, Tables V – 25 : V – 36. A comparison of % Reduction of

Weighted Emissions for both un-weighted and distance-weighted emissions would be helpful.

Response: The percent reduction of un-weighted emissions in Tables V – 25 through V – 31 can be

obtained by a simple formula; 1-(2012 emissions/2007 emissions). For example: In Table V – 25,

the un-weighted emissions for high wind hour 12 are 3.05 tons in 2007 and 2.09 tons in 2012. Using

the formula above (1-(2.09/3.05)) the percent reduction of un-weighted emissions for hour 12 in

Table V – 25 is 31.5%. This compares to 33.8% reduction in distance-weighted emissions. (Note:

Tables V – 32 through V – 36 do not discuss percent reductions of high wind emissions as

incorrectly implied by the comment.)

Comment: Dust Action General Permit claims a 1% benefit in 2012. The DAGP is for windblown

emissions, yet windblown inventory is largely crushing & screening.

Response: The one percent increase in 2012 rule effectiveness attributable to the Dust Action

General Permit applies to land use parcels that are regulated by Maricopa County Rule 310.01 (e.g.,

vacant lots, unpaved roads, etc.). Each high wind domain, upon which high wind emissions are

calculated, contains a wide variety of land uses beyond crushing or screening or other sand & gravel

activities. Each hourly high wind domain is unique (see Figure 6–5 on page 6–17 of main plan)

based upon the local meteorology of that hour. There are many high wind domains that do not

include crushing and screening or other sand and gravel activities as sources of windblown PM-10

emissions. The largest land uses by area within the high wind domains are vacant and open areas.

Also, as shown in Figure 3–1 on page 3–5 of the main plan, the 2008 PM-10 emissions inventory

for the nonattainment area list windblown PM-10 from sand and gravel sources as less than 0.5%

of the inventory, while windblown PM-10 from vacant and open areas each comprise 4% of the

nonattainment area PM-10 inventory. It is therefore inaccurate to assume that the windblown

inventory within the high wind domains is largely crushing and screening activities. 

Temporary Monitor Insights:

Comment:

• In the Temporary Monitor Study, did the temporary meteorological sites conform to EPA

Meteorological Monitoring Guidance for Regulatory Modeling Applications?

• What was the height of each met tower?
26

• Were they monitors calibrated before the research started? Were they audited during the

study?

• Did the study meet data completeness standards?

• The wind direction data are organized into five-degree increments, so concentration

differences could be computed as a function of wind direction V-3. Did the anemometer

used to collect the data provide an accuracy better than +- 5 degrees?

Response: The Temporary Monitor Insights, described on pages V-7 through V-20, in Chapter V

of the Technical Support Document, Appendix B, Exhibit 1 of the Draft MAG 2012 Five Percent

Plan, were derived from monitoring data collected by the Maricopa County Air Quality Department

(MCAQD) beginning in February 2010. Consistent with the study protocol, MCAQD sited,

installed, operated and maintained all instruments in conformance with applicable EPA regulations

and guidance. MCAQD uses the same instruments and applies the same protocols to its existing

monitoring network. Specifically:

• All of the temporary meteorological sites conformed to the EPA Meteorological Monitoring

Guidance for Regulatory Modeling Applications.

• Both met towers were ten meters high (above ground level).

• All anemometers were calibrated before, during and after the study. In addition, all EPA

quality assurance methods were followed for all particulate monitors.

• All particulate and anemometer instruments had data completeness ratios above 90%

meeting EPA’s data completeness standards.

• The anemometer used to collect the data provided an accuracy better than ± 3 degrees.
ACLPI AHJZONA CENTER FOR LAW IN THE PUBLIC INTEREST 

. . 

VIA FACSIMILF (602) 254yi1490 

Lindy Bauer 

Maricopa Association of Governments 

302 N. h Avenut.:, Suite 300 

Phoenix, AZ 85003 

April 12,2012 

RE: Drat\ I\11AG 2012 Five Percl:'!nt Plan for PI\·1-10 for 

the. !Vl<U"icopa County Nonattainment r\rea 

Dear M.s. Bauer: 

'J~Gia•ec ra or,;~;rrng g~vern:n~.nt oc·:ounrJ.::d;r,, il~ci ;mner.rlng ~~~ 1»;3. ria~·~ or Ar'z.~:1•:1: 

Tbank you 'l~)r the opp(,rhnrit)' to comment on the draft State Implementation Plan revision 

("5%) Plan") referenc(~'d above. \A/e provide the follov.;ing comments. 

Particulate p01lution has be~n t1. serious problem in the Valley for the past two decades. Since 

they were first adoptt~d. the Phoenix metropolitan area has never attained the PM-1 0 standards and has 

a long history of prl)p('tsing i.rmclequate pl.ans to address the problem. Now, having once again failed 

to meet its attainment deadline, the :;tate is required under Section 189(d) ofthe Clean Air Act (CA.A) 

to submit ''plan revisions "vhich provide for a.t1a1n .. ment of the PM-1 0 air quality standard and, from the 

date of such submis.si.t;n until nttainr;1,;;nt. /~)r an annual reduction in PM-1 0 or PM-1 0 precursor 

emissions within the ar~a ofn.ot les.-: than 5 percent ofthe amount of such emissions as reponed in the 

most recent inve.ntory prepared f(x such area." 42 U.S.C. §7513(a)(d). In addition to the attainment 

demonstration and 5 ·perc.ent requir~ments. the plans under section 189(d) must address all applicable 

requirements oftbe C /\.A. Wi1.h res peel to 1 he draft plan, we raise the follo\ving cone ems: 

l. BACM and MS~.'L, 

As a serious nonattainrnent area fr)r PMJ 0, the Phoenix area plan must include BACM for all 

significant sources of Pt.'.! 1 0 :ilnd I'M.! 0 precursors. BACM, best available control measures, are the 

maxinltun degree of cnussio.ns r~duetions possible after considering technical and economic 

feasibiUty and envir(rn.rrlcnta! impa<;ts of the control. These must be implemented independent of 

attainment requirements. Also, becmt5¢ Phoenix obtained a five year extension ofits attainment 

deadline, irs plan must inc-lude .MSt\1[ (nw~;t stri.ngent measures). In the General Preamble (59 FR 

41998), EPA sets f<m·.h .a JYtLllti-ste·p proctss fur ident.ifYing BACM/Bl~CT for serious areas. The 

proposed 5% plan doc;:~; not include a B.-~C.i'vf or !\.'fSJ-.I demonstration that follows this process,· 
04/11/2012 14:22 52052'32927 

Comment Letter n: :::!.012 51% P:VH U Pl~ln 

PAGE 02 

Apri112, 2012 

Page 2 of 3 

therefore. it is in.itiid.ly difficult to evt:n determine whether the plan satisfies the BACMIJ\.1SM 

requirement. The st~te cannor rely upon the BACM/MS1vf demonstrations in the 1999 Serious Area 

SIP, as that demonstration wu;:; prepared more than ten years ago, and, and as the EPA recognized in 

its proposed disappmval of t:be. 2007 Drafl. 5% Plan, control measures that previously satisfied the 

BACM requirernent. !.nay nQlonger re:prescnt the ''best availabk' control measure. See, 75 FR 

54806~ 54812. Thert.:·r~)J:'e, an upcbrcd BACtvf/MS!vt analysis should be included in the 5% plan. 

In its propcsd disapprovn.l of the 2007 Draft 5% Plan, EPA found that the 2005 emissions 

inventory relieclupt)l1 by the state t.c' be insufficiently accurate because it overestimated the baseline 

emissions for construed on :a.nd otbcr sourc:;s. Sec 75 FR 54808. In the current plan, MAG is relying 

ttpon a 2008 periodk ,:·missions .~nvenlory which, like the 2005 inventory, was prepared by Jvfaricopa 

County Air Quality .Dc:.~pa.rtment.. At H.r:::;t glc:u1ce. this rnore recent invento1y appears to address EPA's 

concerns as it sho\.vs ~~rn.i.ssior1s from rec;idcntiat constn1ction to be a smaller percentage ofthe overall 

emissions. However,('!. comparison oftbe tW(l i.twentories (and the two draf't plans) reveals a 

discrepancy that MAO doe::: .not appe;:tr to either acknowledge or explain, and that is drastic reduction 

in the estimated e!ni.ssi.ons overall ln the 200.5 inventory) total PM-10 emissions in the nonattainment 

area were calculiltecl i!) he 84.753 tons per yea.r. The 2008 inventory puts that total at 48,148 tons per 

year--a reduction of rnore. !han 40% in just tbree years. It seems highly unlikely that the area achieved 

such a reduction in cmis~ions by the implementa,t.ion of control measw~es. As noted above. we did not 

see any,;vhere in the p.!<-~rl when:.' this huge disparity in the data was acknowledged or explained. This 

oversight should be addressed. Also~ because the inventory is the principal basis for calculating the 

5t;.·1~ annual reducti0n required under the CAA. tt is imp011ant to the public health that the amotllit of . . . 

cmTent emissions (l!C not und.er~~tated. 

3. Reli<!!.~£9...ill2QJ1- .. ~ftL~ .. LQncurrence Regarding Exceedances Claimed As Exceptional 

f,ve.!l1:~ 

We are concern~d th~1t tht~· att·;.,inmenr.demonstr:ation in the 2012 5% Plan, lil<e the 2007 5% 

Plan, relies upon the C:\)ncurren,~e by EPA regarding exceptional events. As the plan acknowledges 

there were 7 exceed~{;1ccs in 2009 alone rh.<tt must be treated as exceptional events in order for the area 

to meet the extended <1ttainm.ent dea.dltne. Further, although the 201 I data has not yet been finalized, 

the injtial data indicat.<:.'.s that tbt.~h:: once ngain a significant nun1be:r of exceedances over multiple days 

and multiple mon1tc;r~:. 'I11e like.iihood of eliminating all ofthese exceedances as exceptional events 

would appear both remote and ~.~ontrary te> the public interest. Therefore, we believe that a plan that 

proposes to achieve "·;l.(taimnent'· simply by white\vashing over severely unhealthf1.tl conditio11S is both 

irresponsible and contrary ~o tbt public interest. 

\\'bile we:! generally support the ;)doption of the general permit requirement for all dust 

generating activities ;.u~d the i.!')Cl'C<Lo:;ed stringency of the agricultural permit requirements, the plan 

does not adequately de.!n.onstt::'i.k that t~i11K:r of these control measllres satisfy the BACM and MSM 

requirement. The plan di.d no1· mcntio!~ iJ1c concerns raised by EPA in its proposed ruler:naking in 
04/11/2812 14:22 52852'3~':lL I 

Comment Letter r·e ;~()! 2 5% PM.-J 0 Plan 

A£. Ct:.Nit:.l"< t"UI"< LAW 

April 12,2012 

Page 3 of3 

2010 regarding the agricultural BMPs or inr.licate whether and ho"v those concerns had been 

addressed. 

We have C(':ltt~rn::; <lhour: the •.::nforceah[Jity of control. measures in the pian. As you know, 

citizen enforcement b ~.::ncoun1ged u.ndcr the Cican Air Act. However, in recent years, when citizens 

have brought action~; to e'nfcJt'Cl~ control rneasurcs that the state is responsible for implementing, the 

state has invoked t:he El.eventh A.rn.ench.ncnt in ~U'l. effort to avoid the enforcement of its obligation to 

comply with the SIP. See Paisley\'. Brewer, CV 2:10-cv-01253-DGC ( D.Ariz.) and Sv.·eat v. Hull, 

200 F. Supp. 2d. 1162 (D. Ariz. 20() l ). Although the defense did not preclude injunctive relief in 

either case, it tmnec·~ssarily ptotracted the litigation and demonstrated a Jack of commitment on the 

part of the state to rultlHing its obligatiN1S under the SlP. Therefore, we believe that where the state or 

one of its subdivision;:; (i.e. :,1 cotmty) <J:;sumes responsibility for the implementation of specific control 

measures, that comm1tment sh~)tdd i.ndude an unequivocal consent to federal jurisdiction if 

enforcement is sought under rhe citizen suit provision. This consent will ensure that the measures are 

ft.tlly enforceable by both EPA r;n1d affected citizens, as the enforcement scheme adopted by the Act 

contemplates. 

Attached to thi~; lctier .i:) a tcclmical revkw of the plan which raises qLtestions and concems 

regarding the mock:J.in~-, incluck.d in. the plan and $UppOJting documents. 

These comment:' :-lre submitted •,Jn bch<1lf of the Sierra Club-Grand Canyon Chapter. 

r·· .. ' 
84/11/2812 14:22 5285292927 AZ Ca-HER FOR LAW 

Technical Reviev.- of MAG 2011 FIVE PERCENT PLAN FOR PM-10 FOR THE 

MARICOPA COUNTY NONATTAINMENT AREA 

On March 12, 20 1.2, The .M~).ricopCI Association of Governments (MAG) published a new 2012 

Draft Five Percent P!a.n [(Jl' 24--hom PM.l 0 for public review. This paper provides comments 

based on the techn.i.c;,d \Vc:>rk <:()mprlsing the draft plan. 

GENERAL 

Ed.itorial CommC'r1t's: 

o The report. pn-:ntides very limited e::xzunples and few calculations to support the reported 

values. 

• The report i.s <'li~o lacking equ.ations to support reported values. 

• The reported vetlue:; <1!'<~ i.n a variety of units, which makes comparisons difficult. 

·MODELING 

Model Selection: 

• The air qual.ity mode-ling den1.onstrat.ion fnr the 24-hour PM I 0 standard is based on U.S. 

EPA's roll bad~ modeling method, Federal regulations state that "all applications of air 

quality t11odelin;· inv,)!ved in this subpart shall be based on the applicable models, data 

bases, and other reqttin::ments specified in appendix \V of this part (Guideline on Ai:r 

Quality Mode b). '' 40 CFR pa.rt § 5 .l.l60(f). 

• Appendix W section 5.:2.2.2 PM I 0; "Re.fined models such as those discussed m 

subsection 4.1.2 are recommended for PM-1 0." 

• Appendix \V Sectio.n. 4.2.2(b) Refined Analytical Techniques; "For a wjde range of 

regulatory applications in al! types of terrain, the recommended model is AERMOD." 

• Appendix W Se-ction 5.2.2.2(e): ''Due to the difficult nature of characterizing and 

modeling fugitive dust a.ncl fi.1gitive emissions, it is recommended that the proposed 

procedure be deared hy U1e Regional Offi.ce for each specific situation before the 

modeling exet:d3e is begun." 

• The rol!back approach !s noi nne of U. S. EPA's preferred methods for demonstrating 

attainmetlt ofdv:; PMlO Ni\/\.QS 
04/11/2012 14:22 5205292927 AZ CErHER FOR LAW PAGE r.J5 

Weighted Rollback: 

• The report dr~.:.-s not pre~}~nl j:o1y or the rollback equations used and so it is LJnc!ear which 

rollback me:tllod '"'as us~c!. 

• If the a:nJ.l,Y:>i~ i1' b~1:sed on the modified rollback method, was a spatial distJibution 

analysis pcrfl.lrmecl? 

• In appendice::; Voi~Ime: 2 p. V - 5, under the Weighted Rollback section, the report states: 

HThe reduct i.(\11 factor i~ calculated on the basis of the distance between each source and 

the impact.ed rnonito.ri.ng site.~· 

o Plea;=;.: pwvicle the equation(s) used for the weighted rollback analysis. Based on 

the s~:Hem.e.nt. above:: it is not clear how MAG has calculated the emissions 

\Vr:dghting. The equations 1 used in EPA's proportional or modified rollback 

method do not involve any interactions among individual sources, only each 

individtw.l :source and a monitor. 

• Rollback typicall~y r<:quires speciatecl profiles of soil dust from ambient measurements 

and chem.k<'l.l analysis for ~OLirce apportionment calculations, using CMB (Chemical 

Mass Balan<.~·;::). Did t\·1ACJ u::;~ .:my source profiles to support the modeling analysis? 

Please re.fer m: "Guidelines t~i PMlO Sampling and Analysis Applicable to Receptor 

Model.i.ng" 

,. MAG 2012 r:[VE PERCENT PLAN FOR PM-10 FOR THE MARICOPA COUNTY 

NONATTAlNMENT AREA. P. 6-44: ''Tbe attainment modeling for the nonattainment 

area demons:r:J.te$ that !.be 24~hour PM.- 1 0 standard will be met by a relatively narrow 

margin in201 2 (i.e .. J 53.8 ugh113 at the \Vest 43rd Avenue monitor)." Was a sensitivity 

analysis perf.lm1ed to t~va.l uate the dt!:gree of contidence in their results? A sensitivity 

analysis n1ay t'~vca.! conditions where the modeling fails or requires improvement, so as 

to ensure the NAAQS are attainr~d according to the plan. 

• Rollback onty 'Narks if rhc monitor is at the point of highest impact. Since air pollution 

standards i1.1\.lSt be atta..\.ned \vi thin the entire planning area and not simply at the monitors, 

how cont1dcnt is MA.G in 1·bcir choice to use a single point to represent the entire 

Maricopa County non<:J!.t.:tinment area'? Dispersion modeling typically provides for a 

more credible product, si nee they more real istica) ly account for spatial and temporal 

patterns. 

• 

• 

Is MAG co.nf;.d:;~l\: that. the recept0r location in the high-wind micro inventory domain is 

representat:i vt of worsl ca~e conditicms? Are there any locations within the high-wind 

domain when: predi.ded concentration::> can be potentjaJly higher than the monitor site? 

According to l"he cbart.s in Fig. V4. Appendix 2. -98.6% of the total exceeding PMIO 

concentra1ion ori.gi.natcs from sources within 2km of the monitor. Under the current 

modeling sccnariQ, ::;and & gravel sources are by far the greatest contributor to PMl 0. 

Yet, the sourc(~ sand ~md gravel source category is also the source category with the 

-------.~---------~ 

1 Rollback Modeling: 8a~i(: and Mod!fii!d. Air Waste a11d Management Association 25:9 (September 1975) 
04/ll/2812 14:22 5205292927 AZ CENTER FOR LAW PAGE 05 

greatest ~sti.mated improvement in R.ul.e Effectiveness. While nearly all of the vacant lots, 

agricultural source:~ and op-::1.1 areas are beyond 2km from the W43rd monitor and 

contribute l~~s~~ than to 1 .4 ~,..n \){their total potential emissions to the monitor. 

• So, the weighted emissions scenario for this model design favors an increase in Rule 

Effectivene~;s oLapproximatel.y 7]<~...;,~ from 40% yielding a net change of -33%. 

111 A quick cotnparison wi.th the average % Reduced o,{Weighted Emissions in Appendix 2. 

P. V - 68, TO\.ble:s V ·25 : V -36, provides a check of the assump6ons. The average 

reduction nccarding lo the cLu-rent: mode! design is very close to the net increase in Rule 

Effectiveness for sand and gmvel operations. 

• If a receptor is pl<w:d in lhe middle of the domain, "vhere there are no sand and gravel 

sources. 'vvi.JI th~ <:missions bt:ne6ts still work? What are the new impacts from vacant 

lots and other nearby :>01.1rces? 

General Modeling: 

• There are: a i.1umb~~!.' of' inaccuracies in appendix 2 p. V-5, Available Modeling Concepts. 

• MAG's ass•~.rtion tht•t .AERMOD is l.es:) accurate than rollback models is baseless. There 

are a numbr:·.r of model e·Ja!Ltation studies2 that test AER.J\10D against a variety of 

regulatory sc(·narios. Jn tile vast majority of cases, AERl'vfOD provides an adequate level 

of conservati::.rn for N AAQS proter.:.tio11. 

• MAG con.clu.dc~; that AEPJv100 model performance is poor for high winds. Yet~ the 

weighted .rollback (lid) meth(Kl u~ed in the 2012 5% pl.an attainment modeling is 

calculated fr0n1 AEJU .. .fO [) model result 

Back trajectory: 

• Appendix. 2, V- 55. Please provide a citation for the back tr~uectory equations? 

o X=·XJ -;-WS*OA47*60*5*SlN(\VD*2*PI/360) 

o Y=Y (t \VS"'0.447*'fi0"' 5*COS(WD*2'~PJ/360) 

• It appears t!iEtt the trnjet:.tories may actually be tangential streamlines and not parcel 

trajectories. According !.0 the t>:qua.tions above~ X and Y are calculated for each hour of 

meteorologica.l duta.. This method creates a simplified representation of a path, because 

streamlines are r:tctua!l;• a series of straight line tangents to a path, in this case one tangent 

for each .nev .. ' hottrly n:x:ord. Trajectories are based on motion equations are more 

representative or a trm~ path. C{)nsidering the "relatively narrow margin" of modeled 

attainment, MAG should perform an additional trajectory sensitivity analysis so that the 

most conservativ,~ donw[n si7.l~ and solJ.rce mix is selected for modeling. 

'- AERMOD AERMOD Eva!U;)t!cms U11d~~: the F.valur.:tions Under the 1-hour N02 and S02 NAAQ.S. lOth Conference 

on Air Quality Modeling: Marc::h 14·, 2012; AEJ~MCD Evaluation for Non-Guideline Applications. 9th Conference on 

J.\ir Quality Modeling October 9. 2008; ~ERMOD: I.·!! test Feettures and Evaluation Results. U.S. EPA, 2003 
84/11/2812 14:22 5285292'327 AL. U:.N I t:.t--: 1- Ut--: LA\!.J 

1 Did ~1/\.G consider using ensemble or matrix trajectories using NOAA's HYSPLIT 

model? The \·miation in. trajectory slart times and location could prove to be a valuable 

form of sen~;itivil:y test D)r ('akulating clomaii1 size and source-mix, 

• Are high v,:in.d back tr~~jectori~s calculated for each monitor and event with high winds in 

2007? How ahnut olhcr yeJ.r:;(.> Will 2008, 2009, 2010 or 2011 have a day that is more 

conservnti v .. ::':' 

Emissions: 

• Appendjx 1. P. V- 62 High Wind Inventories; Were emissions calculated based on winds 

speeds f!·o:n rnctcoro!.ogjc:al mo11itor, or wind speeds calculated at each back trajectory 

location? 

• Appendix 2. P. V- 67 '·Tb~ calculated emissions for each land use parcel are divided by 

the distance (ket) from tbe. rnod·:ded monitor." Please provide these calculations. 

• Appendix ? .. P. V - 68, Table~ V -25 : V -36. It is very difficult to compare tons to 

tons/feet (if at aln . .Pl.~a~e cxple1in the units tons/feet. Are the tons/feet estimates the 

emissions eqaiv~.l.enl t(, lJ.1t.! sottrce receptor interaction coefficient ( x/Q)? If so, please 

explain, 

• Appendix 2. P V- 6~, labl~s V -25 : V -36. A comparison of% Redl.lcf.ion of W'"eighted 

Emissions for both un-v-·cighti!d a.nd distance-weighted emissions would be helpflll. 

• Dust Action Cencra! Permit claim~> a 1% benefit in 2012. The DAGP is for windblown 

emissions, yet '-Vindblown i:wcntory is largely crushing & screening. 

Temporary Monitor .fnsights: 

• In the Tempomry :tvfonitor Stt.,.dy, did the temporary meteorological sites conform to EPA. 

Meteorological Monitoring Guidance for Re&,rttlatory Modeling Applications? 

• What was th·~ l·K~ight of ~~acl.1 met tower'? 

• Were they rnon~tors caJibmtcd before the research started? Were they audited during the 

study? 

• Did the study rn~d d:~lil completeness standards? 

• The wind din;:ction d<m'l arc- c~rganized into fivt)-degree increments~ so concentration 

differences could be cornrmte::cl os a function of wind direction V- 3. Did the anemometer 

used to collect the data provide ;;m accuracy better than +-5 degrees? 
APPENDIX E

EXHIBIT 2:

Certification of Adoption
RESOLUTION TO ADOPT THE MAG 20 12 FIVE PERCENT PLAN FOR PM-I 0 

FOR THE MARICOPA COUNTY NONATIAINMENT AREA 

WHEREAS, the Maricopa Association of Governments (MAG) is a Council of Governments 

composed of twenty-five cities and towns within Maricopa County and the contiguous urbanized area, the 

County of Maricopa, the Gila River Indian Community, the Salt River Pima-Maricopa Indian Community, 

Fort McDowell Yavapai Nation, Arizona Department of Transportation, and Citizens Transportation 

Oversight Committee; and 

WHEREAS, the Governor of Arizona designated MAG as the regional air quality planning agency 

and metropolitan planning organization for transportation in Maricopa County; and 

WHEREAS, the Maricopa County nonattainment area is classified as a Serious Area for PM-I 0 

particulate matter according to the Clean Air Act; and 

WHEREAS, the MAG 2007 Five Percent Plan for PM-I 0 was required by the Clean Air Act since 

the Maricopa County nonattainment area failed to attain the PM-I 0 standard by December 3 I, 2006; and 

WHEREAS, the MAG 2007 Five Percent Plan for PM-I 0 was voluntarily withdrawn on January 25, 

20 I I to include new information, such as the new Environmental Protection Agency equation for paved 

road dust emissions; and 

WHEREAS, the MAG 20 12 Five Percent Plan for PM-I 0 is a replacement for the 2007 plan that was 

withdrawn; and 

WHEREAS, the plan is required to reduce PM-I 0 emissions by at least five percent per year until 

the standard is met; and 

WHEREAS, MAG has prepared the 20 12 Five Percent Plan for PM-I 0 for the Maricopa County 

Nonattainment Area; and 

WHEREAS, A.R.S. 49-406 H. requires that the governing body of the metropolitan planning 

organization adopt the nonattainment area plan. 

NOW THEREFORE, BE IT RESOLVED BY THE MARICOPA ASSOCIATION OF 

GOVERNMENTS REGIONAL COUNCIL as follows: 

SECTION I . That the MAG Regional Council adopts the MAG 20 12 Five Percent Plan for PM-I 0 

for the Maricopa County Nonattainment Area which contains control measures from the State and local 

governments. 

SECTION 2. That the MAG Regional Council further recommends implementation of the 

appropriate measures by the MAG cities and towns, Maricopa County, and the State of Arizona and 

authorizes the submission of the plan to the Arizona Department of Environmental Quality and the U.S. 

Environmental Protection Agency. 
PASSED AND ADOPTED BY THE REGIONAL COUNCIL OF THE MARICOPA ASSOCIATION OF 

GOVERNMENTS THIS TWENTY-THIRD DAY OF MAY 2012. 

ATTEST: 

MAG Regional Council 

Dennis Smith 

Executive Director 
CERTIFICATION OF ADOPTION OF THE 

MAG 2012 FIVE PERCENT PLAN FOR PM-10 

FOR THE MARICOPA COUNTY NONATTAINMENT AREA 

An Excerpt from the May 23, 2012 MAG Regional Council Meeting Minutes 

Mayor Michael Le Vault moved to adopt the MAG 2012 Five Percent Plan for PM -10 for 

the Maricopa County Nonattainment Area. Supervisor Max Wilson seconded, and the 

motion passed unanimously. 

I certify that on May 23, 2012, the MAG Regional Council adopted the MAG 2012 Five Percent Plan for 

PM -10 for the Maricopa County Nonattainment Area. 

Date 
· wu<.tv couH 

f14¥UIIM" 

... · 

OFFICE: OF THE GOVERNOR 

S'i'~TI!: HOUSI!: 

PHOCNIX, ARIZONA 85007 

'February 1, 1918 

Tho Honorable Dougla.s M. Costlo 

Ad!nin.Utr:1tor. 

United Stat~ Environmental Protection A&cncy 

401 .nM,. Street, S.W. 

\Vuhiniton, DC 20460 · 

Deu M'r. Costte: 

In accordance with s~ction t 74(a) of the Clean Nr Ao: as am~:tded August 7, 

)911, I hereby d~iilltnte the· Maricopa A.uociati()n of Ciovcmrnents u the le:~d 

planning orpniutlon for Maricopa ·county, (PhoeniX) Arl%ona nnd tho Ptma 

Association oi'Co~rnments u the lc:td planiling o~tlon for Pima Colinty, 

(Tuaon) Alitonn for tlte purpose of determi.1lng which elements or .a· revised Nr c. 

Quallt'/ lmplemencaUon Plan:will be planned, !mp!em;ntcd and ftnfotced by the 

State and local sovemments in Arl%ona. Attached :tre lett<iss Crom each agcn1::t requesting suCh d~ignatiom.. · · . . 

This aC:t!o.n is requited be~we n:~tional prim:Ur am.bi~nt rur quality scandimu' for 

oarl;lon monoxide and photochem!c::11 oxidants will not be atc~b1ed In metropolitan 

PhoeniX and Tuaon by July 1, 1919. De.l3ilcd a~ements with the ·above 

organiutlons of elected ofilc!:ls of loc:tl· govem.ments' nnd I he ~lute of Ari:ona · arc now bein~ de•te!opcd. These ug:recments wUI Identify the rcspon~ibillllcs of each · of the partlc:ipnnts, I.e. the Maricopa Association of Ciovernm~nts, the Pima 

Association of Governments,: the Maricopa· County f{ealth Depa.rtme:u, and the 

Arizona Department of Hedth Scrvlc=: ~pon completion oi such agreements, they 

will be ccrtifled by this office and for.vardcd to the U.S. E.1vironmen~ P:otection Ai=n~/· · ~ 

ws:vabcim 

Attac:lunen u · 

cc:: Su~Me Dandoy 

Bruce Scott 

0. Kenneth Driggs 

11tomn:s L. Sw:utson 

Paul De Fdco, Ir. 

0-2 
STATE OF A;RIZONA 

EXECUTIVE OFFICE 

FIFE SYMINGTON 

Oovernor 

The Honorable Charles Hayes 

Chairman, MAG Regional Council· 

1820 West Washington 

. Phoenix, P(Z 85007 

Dear Mayor Hayes: 

June 24, 1993 

. I concur with your May lOth letter-~MAG should coordinate its aviation 

planning with the statewide ·aviation planning effort. 

Please inform the Regional Council that I support their .continuation as the 

Metropolitan Planning Organization. I believe the MAG Regional Aviation System 

Plan will do much .to help your region of the state make decisions on airport 

improvements. I salute your process. · · 

If you are not aware, however, my Regional Airport Feasibility Assessment · 

(RAFA) was a statewide aviation planning effort. In the case of the RAFA, regional 

does not mean a limited area like MAG but means the Southwestern United States. 

My RAFA study was paid for by FAA funding and focused on the statewide issue of 

a· new major airport facility to serve needs throughout Arizona and the entire 

. Southwest within the next 20 to 30 years. It also considers long-term economic 

effects on the state. Your MAG RASP was also paid for by FAA funding but focused 

on 10 to 20 years of airport improvements in Maricopa County. As you can see, the 

two studies differ greatly in scope and substance. · 

RECTi j u N ?!.: )~ ·;993 

1700 WEST WASHINGTON. PHOENIX, ARIZONA 85007 • (602) 542·4331 
The Honorable Charles Hayes 

June 24,1993 

Page Two 

. I ~otice that about a dozen of your MAG RASP Committ.ee Members were 

also on my GRAAC Committee. It seems to me that this overlap of membership 

provides a good b.asis for the coordination y~m seek. · 

Thank you for yo11r continued concern to keep Arizona's aviation industry 

viable and vital in the 21st century._ 

FS/JL:me 

Sincereiy, 

Fife .Symington 

GOVERNOR. 

cc: Joe Lane, Executive Assistant for the Governor 

Marvin Cohen, GRAAC Chairman 

Linda Brock-Nelson, GRAAC Vice Chairman 

GRAAC Committee Members 

MAG Regional Council · 

. ' 

., 
 

49-406. Nonattainment area plan

A. For any ozone, carbon monoxide or particulate nonattainment or maintenance

area the governor shall certify the metropolitan planning organization designated to

conduct the continuing, cooperative and comprehensive transportation planning

process for that area under 23 United States Code section 134 as the agency

responsible for the development of a nonattainment or maintenance area plan for

that area.

B. For any ozone, carbon monoxide or particulate nonattainment or maintenance

area for which no metropolitan planning organization exists, the department shall be

certified as the agency responsible for development of a nonattainment or

maintenance area plan for that area.

C. For any ozone, carbon monoxide or particulate nonattainment or maintenance

area, the department, the planning agency certified pursuant to subsection A of this

section on behalf of elected officials of affected local government, the county air

pollution control department or district, and the department of transportation shall,

by November 15, 1992, and from time to time as necessary, jointly review and

update planning procedures or develop new procedures.

D. In preparing the procedures described in subsection C of this section, the

department, the planning agency certified pursuant to subsection A of this section on

behalf of elected officials of affected local government, the county air pollution

control department or district, and the department of transportation shall determine

which elements of each revised implementation plan will be developed, adopted, and

implemented, through means including enforcement, by the state and which by local

governments or regional agencies, or any combination of local governments, regional

agencies or the state.

E. The department, the planning agency certified pursuant to subsection A of this

section on behalf of elected officials of affected local government, the county air

pollution control department or district, and the department of transportation shall

enter into a memorandum of agreement for the purpose of coordinating the

implementation of the procedures described in subsection C and D of this section.

F. At a minimum, the memorandum of agreement shall contain:

1. The relevant responsibilities and authorities of each of the coordinating agencies.

2. As appropriate, procedures, schedules and responsibilities for development of

nonattainment or maintenance area plans or plan revisions and for determining

reasonable further progress.

3. Assurances for adequate plan implementation.

4. Procedures and responsibilities for tracking plan implementation.

5. Responsibilities for preparing demographic projections including land use, housing,

and employment.

6. Coordination with transportation programs.

7. Procedures and responsibilities for adoption of control measures and emissions

limitations.

8. Responsibilities for collecting air quality, transportation and emissions data.

9. Responsibility for conducting air quality modeling.

10. Responsibility for administering and enforcing stationary source controls.

11. Provisions for the timely and periodic sharing of all data and information among

the signatories relating to:

(a) Demographics.

(b) Transportation.

(c) Emissions inventories.

(d) Assumptions used in developing the model.

(e) Results of modeling done in support of the plan.

(f) Monitoring data.

G. Each agency that commits to implement any emission limitation or other control

measure, means or technique contained in the implementation plan shall describe

that commitment in a resolution adopted by the appropriate governing body of the

agency. The resolution shall specify the following:

1. Its authority for implementing the limitation or measure as provided in statute,

ordinance or rule.

2. A program for the enforcement of the limitation or measure.

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3. The level of personnel and funding allocated to the implementation of the

measure.

H. The state, in accordance with the rules adopted pursuant to section 49-404, and

the governing body of the metropolitan planning organization shall adopt each

nonattainment or maintenance area plan developed by a certified metropolitan

planning organization. The adopted nonattainment or maintenance area plan shall be

transmitted to the department for inclusion in the state implementation plan

provided for under section 49-404.

I. After adoption of a nonattainment or maintenance area plan, if on the basis of the

reasonable further progress determination described in subsection F of this section or

other information, the control officer determines that any person has failed to

implement an emission limitation or other control measure, means or technique as

described in the resolution adopted pursuant to subsection G of this section, the

control officer shall issue a written finding to the person, and shall provide an

opportunity to confer. If the control officer subsequently determines that the failure

has not been corrected, the county attorney, at the request of the control officer,

shall file an action in superior court for a preliminary injunction, a permanent

injunction, or any other relief provided by law.

J. After adoption of a nonattainment or maintenance area plan, if, on the basis of the

reasonable further progress determination described in subsection F of this section or

other information, the director determines that any person has failed to implement

an emission limitation or other control measure, means or technique as described in

the resolution adopted pursuant to subsection G of this section, and that the control

officer has failed to act pursuant to subsection I of this section, the director shall

issue a written finding to the person and shall provide an opportunity to confer. If the

director subsequently determines that the failure has not been corrected, the

attorney general, at the request of the director, shall file an action in superior court

for a preliminary injunction, a permanent injunction, or any other relief provided by

law.

K. Notwithstanding subsections A and B of this section, in any metropolitan area with

a metropolitan statistical area population of less than two hundred fifty thousand

persons, the governor shall designate an agency that meets the criteria of section

174 of the clean air act and that is recommended by the city that causes the

metropolitan area to exist and the affected county. That agency shall prepare and

adopt the nonattainment or maintenance area plan. If the governor does not

designate an agency, the department shall be certified as the agency responsible for

the development of a nonattainment or maintenance area plan for that area.

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