4-127 Section 92.2.1.4 – Prohibition of Dust Over Property

Line:

No O WNER A ND /O R O PERATOR of an unpaved parking lot shall permit a dust plume from an unpaved parking lot to cross a property line, provided however, that th is requirement shall not be applicable where the owner and/or operator has applied B EST A VAILABLE C ONTROL M EASURES provided for in this regulation.

Section 93.2.1.2 New Section :

New C ONSTRUCTION , M ODIFICATION , or approvals
of P AVED roads on which vehicular traffic is equal to or greater than 3,000 vehicles per day shall be
constructed with a P AVED travel section, and eight (8) feet of stabilized shoulder adjacent to

the P AVED travel section where right-of-way is
available for the stabiliz ed shoulder. Where rightof-way is not available for the full eight (8) feet of stabilized shoulder, curbing shall be installed adjacent to the shoulder. Stabilized shoulders must be maintained in compliance with the
stabilization standards set forth in Subsection 93.2.1.7 of this Regulation.

Section 93.2.2 and Section 93.2.3 New Sections :

93.2.2 Equipment Prohibition: The use of dry rotary brushes and blower devices for removal of dirt, rock, or other debris from a paved road is expressly prohibited, except where preceded or accompanied by sufficient wetting to limit the visible emissions to an opacity of not greater that 20% opacity as set
forth in Subsection 93.5.1.1

93.2.3 Crack Seal Equipment Requirements: After adoption of this Subsection,4-128 any O WNER A ND /O R O PERATOR which utilizes crack seal equipment shall acquire or contract to acquire only vacuum type crack seal equipment.

Section 94.5.4 New Section:

No person shall cause or permit the handling, transporting, or storage of any material in a manner that allows any dust plume to extend more than 100 feet, horizonta lly or vertically, from the point of origin or allow any dust plume to cross a property line, prov ided however, that the requirements of this Subsection shall not be applicable where B EST A VAILABLE C ONTROL M EASURES required by this Regulation are fully implemented.

Section 94.5.9 New Section:

Equipment Prohibition: The use of dry rotary
brushes and blower devices for removal of deposited mud/dirt carryout from a paved road is expressly prohibited, ex cept where preceded or accompanied by sufficient wetting to limit the visible emissions to an opacity of not greater than 20% opacity as set forth in Subsection 94.9.2.

4.8.3 Control Measure Commitments

4.8.3.1 Commitment to Pave Unpaved Roads Unpaved roads with identified ADT of 150 or greater will be paved by Clark County Public Works, City of North Las Vegas Public Works, City of Las Vegas Public Works, and City of Henderson Public Works by using CMAQ funds by June 1, 2003. The City of Las Vegas has made an additional commitment to pave all unpaved roads within their ju risdiction by the end of
2006. An extranet web site tracking the paving of the unpaved roads will be established by April 30, 2001 and maintained until all unpaved roads with greater than 150 ADT have been paved. Although this commitment does not include unpaved roads less than 150 ADT outside the City of Las Vegas, unpav ed roads with less than 150 ADT have and may continue to be paved as part of the local ERC program. Annual updates on the progress of Commitment To Pave
Greater than 150 ADT Unpaved Roads4-129 paving all roads will be subm itted to Clark County AQD
and U. S. EPA.

4.8.3.2 Commitment to Stab ilize Shoulders of Paved

Roads Nevada Department of Transportation, Clark County Public Works, City of Nort h Las Vegas Public Works, City of Las Vegas Public Wo rks, and City of Henderson Public Works departments will identify the roadways in their respective jurisdictions that have a paved section
less than 28 feet. For roadw ays that are not to be improved over the next five years, emission estimates using a consistent methodol ogy will be calculated by each entity in conjunction with CCDCP. The shoulder improvements and road paving for unpaved roads with less than 150 ADT will be prioritized by each entity for their respective jurisdictions based upon emission estimates. At a minimum, funds will be obligated to improve 33 miles of paved roads with unstabilized shoulders to meet Section 93 standards by December 31, 2003 and all unstabilized shoulders will be improved to meet Section standards by December 31, 2006.

The prioritized list of shoulder improvements to meet Section 93 standards and pav ing of unpaved roads with less than 150 ADT, and ident ified funding sources will be incorporated into a plan by each entity for their respective jurisdictions. Plans will be completed by February 15, 2002. Annual up dates on the progress of stabilizing shoulders will be submitted to Clark County
AQD and U. S. EPA.

The current (fiscal year 2001 through fiscal year 2003) Transportation Improvement Pr ogram (TIP) commits the use of CMAQ funds not to exceed $25 million to meet

the PM 10 SIP commitments. This will result in the obligation of these funds to roadway shoulder improvements and to the pavi ng of unpaved roads by June 30, 2003, in accordance with each entity’s plan. The CMAQ funds beyond fiscal year 2003 will be first committed to the carbon monoxide transportation demand management (TDM) program, and then the necessary funds will be committed to complete each Commitment To Stabilize Shoulders by
the End of 20064-130 entity’s plan for stabili zing shoulders and paving unpaved roads by December 31, 2006.

4.8.4 Commitment to Enc ourage Adoption of Dust Suppressant Product Specifications

The issue of unintended adver se environmental impacts
is noted in the discussion of the Section 90 requirements for disturbed open areas. As noted in the analysis, the risks, while thought to be slight, are real. The absence of a product standard also prevents product applicators, contract ors, developers, and public agencies from including approved product specifications in purchase contracts and bid specifications. Because of the scope of this undertaking and the clear applicability to areas outside Clark County, the County believes that development of the standard and the implementation of a limited field testing program needs
to be done at the state or federal level. As set forth under research commitments, Clark County is committed to assisting in the funding and coordination of research studies that are needed to develop appropriate product specifications. Clark County will also work with the NDEP and U. S. EPA Regi on IX to facilitate the adoption of dust control product specifications and a dust control product field testing program.

Clark County is an active participant of the dust palliatives working group and has helped to sponsor the activities of the working group. Clark County will continue to support the working group until dust palliative standards are adopted at the state or federal

level.

4.9 SUMMARY OF CLARK COUNTY CONTROL

MEASURES AND AIR QUALITY PROGRAMS

As indicated in the introduction to this chapter, Clark County’s PM 10 is dominated by geologic materials from fugitive dust area sources. T herefore, the focus of this
SIP is on control of these area dust sources: Development of Dust Suppressant Product Specification a Priority4-131 disturbed open areas, construction activities, paved roads, and unpaved roads. These controls are implemented through Sections 90, 91, 92, 93, and 94 of the AQD Air Quality Regulati ons. These regulations are very comprehensive and contain a number of innovative concepts that Clark County believes will substantially
reduce emissions from these sources. In particular, Clark County believes that t he provisions of Section 94 (Construction Activities) and the companion Section 94

Handbook will set the standard by which other fugitive dust control regulatory pr ograms will be judged in the
future.

Some uncertainties in elem ents of the SIP are noted. The emission inventory for unpaved roads is acknowledged to have some omissions and the inventory for disturbed open areas needs to be updated regularly. Certain major sources might have air quality impacts on nearby neighbor hood areas. Certain
emission factors for source s that are of critical importance in the Las Vegas Valley may require further verification. This SIP puts fo rward a series of ambitious research programs to address these uncertainties.

This SIP demonstrates that all significant sources of

PM 10 in the Las Vegas Valley will have BACM applied at the earliest practicable date. These measures also meet the U. S. EPA requirements for RACM.

4.10 PLAN IMPLEMENTATION

The State of Nevada program for the control of air pollution is established in Chapter 445B of the Nevada Revised Statutes (NRS). NRS 445B.100 states that it is the public policy of the St ate of Nevada and the purpose of NRS 445B.100 to 445B.640, inclusive, to achieve and maintain levels of air qua lity which will protect human health and safety. NRS 445B.500 delegates the authority to the District Board of Health of Clark County to establish a program for t he control of air pollution and administer the program within its jurisdiction. The
District Board of Health of Clark County adopted Air Quality Regulation, Section 2 designating the Board of
Health as the Air Pollution Control Board of Clark County and the incorporated citi es in Clark County. It
establishes the Board’s author ity to establish such Clark County Has the Authority to Implement
the SIP4-132 emission control requirements as may be necessary to prevent, abate, or control air pollution, to establish procedures and compliance schedules to enforce those regulations, to levy penalties and to seek criminal fines against violators. Appendix L provides details on AQD
dust control enforcem ent programs.

The District Board of Health of Clark County ensures

that the resources needed to implement the air quality program are provided. Future year resource requirements are projected as follows:

FY 2001-2002 $12,133,422

FY 2003-2004 $12,573,490

FY 2005-2006 $15,079,268

The State of Nevada has the responsibility for ensuring the adequate implementation of the Clark County air pollution control program. Assurances for this requirement are satisfied through NRS 445B.520 which
allows the State Environmental Commission to supersede a County’s program in instances when the
Commission determines that a local air quality program is inadequate. The State of Nevada Has Oversight5-1 

## CHAPTER 5: DEMONSTRATION OF ATTAINMENT
OF PM 10 

## NATIONAL AMBIENT AIR QUALITY
STANDARDS

5.1 INTRODUCTION

The purpose of this PM 10 State Implementation

Plan is to assess whether control measures adopted since 1998 (Reasonably Achievable Control Measures [RACM] and Best Available Control Measures [BACM]) reduce PM 10 emissions sufficiently to demonstrate attainment of the annual
and 24-hour national ambient air quality standards
for PM 10 no later than Decem ber 31, 2001. This attainment demonstration, or test, must show that the nonattainment region wil l reach attainment by
the end of 2001. As demonstrat ed in this chapter of the SIP, the annual standar d will be attained in
2001 but the 24-hour NAAQ S cannot be attained until 2006. An explanation of why Clark County projects attainment of the 24-hour standard in 2006
instead of the current deadl ine of 2001 specified by the Clean Air Act (Act) is found in Chapter 7.

The modeling process used to demonstrate
attainment is described in Appendix K. There are several key elements for attainment demonstration, including an assessment of future air quality conditions, a summary of committed control measure impacts, and projec ted attainment status. Future air quality conditions were described in Chapter 3. The contro l measures that have been adopted are described in Chapt er 4. This chapter addresses the impacts of the control measures and the projected attainment st atus. This chapter also addresses reasonable further progress and the transportation conformity budget.

5.2 DESIGN VALUE SELECTION

In accordance with U. S. EPA serious area guidance, represent ative 24-hour and annual average PM 10 concentrations are needed to5-2 estimate the amount of emission reductions required to demonstrate attainment of the standards. These high c oncentrations, referred to as design values, are used to determine the type
and level of controls needed to attain both standards. They represent the “starting point” for
ambient levels of PM 10 and determine the quantity of reductions necessary to meet the standards. For example, if the design value for the annual standard

is 53 μ g/m 3 , the State Implementation Plan (SIP)

measures must result in at least a 3 μ g/m 3

reduction to meet the standard.

5.2.1 Annual Design Value Concentration

The base year design value for the Las Vegas Valley nonattainment area, determined with 1997, 1998, and 1999 PM 10 monitoring data, is 53 μ g/m 3
for the annual standard. The development of the annual design concentration is relatively straightforward. If one or more years of ambient

PM 10 measurements are available for a site, the design concentration is the average of the observed

annual arithmetic means. 1 The annual arithmetic means were averaged for all monitoring stations described in Chapter 2. The only station where the average of the means from 1997 through 1999

exceeded the annual N AAQS was J. D.
Smith/McDaniel. The McD aniel station was moved during the evaluation peri od due to the loss of the lease for the site, and the monitor was located at the nearby J. D. Smith Middle School. The site is
now referred to as the J. D. Smith site. The average of the annual ar ithmetic mean is 53 μ g/m 3

. Therefore, the base y ear annual design value

concentration will be 53 μ g/m 3

.

The base year design value, in conjunction with the
increase or decrease of emissions from 1998 to 2001, are then used to project attainment year concentrations or design values in 2001. The U. S. EPA recommends a combination of receptor and

1 PM 10 Guideline Document , United States Environmental Protection Agenc y, Office of Air Quality Planning and Standards; Research Triangle Park, North Carolina, April 1993. Annual Design Value

is 53 μ g/m 35-3 dispersion models combined with reliable emission projections to model attainment with national ambient air quality standards in a future year.

However, accurately modeling PM 10 air quality in a future year in accordance with U. S. EPA recommendations is a difficult objective. Problem areas remain with respect to both emission inventories and modeling te chniques. There are circumstances where receptor models are not capable of quantif ying absolute PM 10 emission estimates (such as urban locations where a large fraction of particulate emissions are from non-traditional sources like construction operations, unpaved roads, and wind-blown fugitive dust). Dispersion models also have limitations. For example, as part of the Las Vegas Valley PM 10 Study , the Desert Research Institute attempted to
model PM 10 emissions within a micro-scale area of the valley’s nonattainment area utilizing the Chemical Mass Balance (CMB) receptor model, 2
the Fugitive Dust Model (FDM), and the Industrial Source Complex 3 (ISC3) Gaussian plume dispersion model. 3 The receptor modeling
results attributed over 80 percent of the ambient concentration to fugitive dust sources, but could not distinguish between the f ugitive dust sources. Uncertainties regarding emi ssion rates, in terms of timing and location (e.g., construction activities versus paved road dust) present problems in obtaining valid results fr om dispersion models.
These issues are discussed in more detail in Appendix K.

Therefore, the project ed annual design value for 2001 (as an indicator of attainment) will be derived by changing the base year design concentration of

53 μ g/m 3 by the same percentage as the change
between the total amount of PM 10 emissions emitted throughout the valley between 1998 and 2001. This application assumes that as valley-wide

2 Fugitive Dust and Other Source Contributions to PM 10 in Nevada’s Las Vegas Valley. Vol. II, Draft Final Report , Desert Research Institute, Reno, Nevada, August 30, 1996.

3 Fugitive Dust and Other Source Contributions to PM 10 in Nevada’s Las Vegas Valley. Vol. II, Final Report , Desert Research Institute, Reno, Nevada, April 18, 1997. Accurately Modeling

PM 10 Ambient
Concentrations for

Future Years Is

Problematic5-4 PM 10 emissions change, then so would design concentrations. In other words, there would be a proportional relationshi p between emissions and ambient concentration. This methodology is commonly known as the proportional rollback
model.

Tables 3-3 and 3-8 indicate that emissions generated in 2001 would be slightly lower than those generated in 1998. The lower emission
estimates are based on a decrease in vacant land. Vacant land acreage is anticipated to decrease as development within the BLM disposal area continues. Although thes e numbers are the best estimates available, t here are no guarantees the vacant land will be developed. Due to the uncertainty regarding the number of acres of vacant land and the corresponding emissions from this source, the proportional ambient concentration may not be reduced by the amount projected by the emissions inventory. Therefore, as a conservative, health-protective step, the projected annual design value will not be

lowered but will be set at 53 μ g/m 3

.

5.2.2 24-Hour Design Day Concentrations

The development of the 24-hour design concentrations was more complex than the annual average. Appendix A det ails the 24-hour design value selection process. The design values exceed the 24-hour NAAQS at five monitoring stations in Hydrographic Basin 212: Craig Road, East Flamingo, Green Valley, J. D. Smith, and Pittman. The design value for each site and the date it was monitored is presented in Table 3-6. These sites are representative of typi cal conditions and sources that lead to high levels of PM 10 in the BLM disposal
area. Other sites within the BLM disposal area with similar sources surrounding them may be present or develop as growth continues within the
nonattainment area. In that event, these sites could be utilized to represent the sources affecting PM 10 levels in these areas and the impact of the implementation of the SIP control measures. As Although Emissions
Are Lower in 2001 Than in 1998, the Design Value Is Held

at 53 μ g/m 3

Design Values Stay

the Same for the
Micro-Scale Sites5-5 these sites are consid ered representative of potential future areas, neither the emissions inventories nor the design va lues were projected for 2001. Reviewing the meteor ological conditions on the days these design values were recorded, the design values occurred when:

• hourly average winds exceeded 15 mph;

• wind speeds exceeded the threshold friction velocity for soils within the Las Vegas Valley;

• climatological conditions did not meet the Natural Event definition; and

• PM 10 precursors (compounds leading to condensable and secondary particulate formation) did not play a major role in the
violations of the NAAQS.

In addition to the design value for each of the five monitoring sites where vi olations of the NAAQS were measured, a valley-wide design value was also developed for the purpos es of the attainment demonstration and the development of a transportation conformity budget. Consistent with U. S. EPA policy, the 24-hour valley-wide design

value was chosen on the basis that it was the third highest of each of the highest 24-hour concentrations measured in a calendar year. It is the highest concentration measured in 1998, the annual base year; and the day it was measured, December 21, 1998, is in roughly the same time
frame as the other 24-hour design days. The 24- hour design value for the valley-wide inventory is

281 μ g/m 3

.

As with the annual valley-wi de inventory, the total emissions for the design day presented in Table 3-5 are higher than the total 2001 emissions. Again, this change is based largel y on the acres of vacant land that are anticipated being developed between 1998 and 2001. As previously mentioned, the emissions are based upon assumptions that may or may not be realized. Ther efore, as a conservative, health-protective step, the projected valley-wide 24- hour design value will not be lowered but will be set

at 281 μ g/m 3 . This is a conservative approach The Valley-Wide 24- Hour Design Value

Is 281 μ g/m 35-6 because the higher design va lue will require greater controls than a lower design value that would be calculated based upon t he lower projected
emissions.

5.3 RELATING DESIGN VALUES TO EMISSION
INVENTORIES

Due to problems with dispersion and receptor models described earlier, the proportional rollback method was applied to estimate the relationship between region-wide PM 10 emissions and sampled

PM 10 concentrations. The rollback method
assumes ambient PM 10 concentrations in excess of background values are proportional to region-wide emissions. As stated previously, the design day

concentration of 281 μ g/m 3 is considered proportional to the 24-hour valley-wide inventory although it was measured at only one site. The annual emissions inventory will be reduced by the same percentage for each source as the control

measures will reduce emissi ons in the J. D. Smith micro-inventory area for t he sources that appear in
both inventories. The annual design value of 53

μ g/m 3 will be used for the J. D. Smith annual inventory and the valle y-wide inventory.

To ensure the proportional rollback modeling results were sound enough to evaluate controls needed to attain the NAAQS on a valley-wide basis,five additional micro-scale inventories (microinventories) were complet ed at the five sites where design concentrations exceeded the 24-hour
NAAQS. The 24-hour micr o-scale inventories are related to the values measured at the respective monitoring location and the same rollback method
will be used to demonstrate attainment.

Tables 5-1 through 5-8 demonstrate the proportional rollback model ing results for the attainment year of 2001 us ing the design values as
described above. These m odels present the impact on, or contribution to, the design concentrations in 2001 before any proposed PM 10 control reductions take place. Proportional Rollback Modeling
Will Be Performed
for Five Micro-Scale
Sites as Well as Valley-Wide5-7 Table 5-1

2001 Annual BLM Disposal Area Uncontrolled PM 10 Emissions, Percent
Contribution and Concentration

SOURCES PM 10 (tons/year) Percent
Contribution Impact on Design Concentration ( μ g/m 3 ) Stationary Point Sources
Sand & Gravel O perations 627 0.37 0.13

Utilities – Natural Gas 199 0.12 0.04 Asphalt Concrete Manufacture 171 0.10 0.04

Industrial Processes 80 0.05 0.02

Other Sources 124 0.07 0.03
Total 1,201 0.70 0.26 Stationary Area Sources
Small Point Sources 184 0.11 0.04

Residential Firewood 89 0.05 0.02

Residential Natural Gas 79 0.05 0.02

Commercial Natural Gas 33.2 0.02 0.01

Industrial Natural Gas 14 0.01 0.00

NG – Purchased at the Sour ce – Carried by SWG 210 0.12 0.04
Structural / Vehicle Fires / Wild Fires 20 0.01 0.00 Charbroiling / Meat Cooking 889 0.52 0.19

Disturbed Vacant Lands / U npaved Parking Lots 33,100 19.40 7.08 Native Desert Fugitive Dust 9,520 5.58 2.04

Stabilized Vacant Lan ds Dust 3,640 2.13 0.78 Construction Activity Fugitive Dust 23,109 13.54 4.94 Windblown Construction Dust 18,381 10.77 3.93
Total 89,269 52.32 19.10

Nonroad Mobile Sources Airport Support Equipment 44 0.03 0.01 Commercial Equipment 0.3 0.00 0.00 Construction & Mining Equipment 428 0.25 0.09 Lawn & Garden Equipment 15 0.01 0.00 Railroad Equipment 17 0.01 0.00

Recreational E quipment 1.0 0.00 0.00 McCarran International Airport 297 0.17 0.06 Henderson Executive Airport 7 0.00 0.00 North Las Vegas Municipal Airport 27 0.02 0.01

Nellis Air Force Base 31.9 0.02 0.01

Total 867 0.51 0.19

Onroad Mobile Sources Paved Road Dust (Includes C onstruction Track Out) 55,005 32.24 11.77 Unpaved Road Dust 18,932 11.10 4.05 Highway Construction Projects Activities 2,782 1.63 0.60 Highway Construction Projects – Wind Erosion 1,470 0.86 0.31
Vehicular Sulfate PM 489 0.29 0.10

Vehicular Tire Wear 100 0.07 0.02

Vehicular Brake Wear 163 0.10 0.03

Vehicular Exhaust 346 0.20 0.07
Total 79,287 46.47 16.96 Background* 16.5

Total 170,625 100.00% 53

*Background includes 13 μ g/m 3 annual average concentration meas ured at the Jean monitoring

station and 3.5 μ g/m 3 of secondary particulate.5-8 Table 5-2

J. D. Smith 2001 Annual Uncontrolle d Emissions Inventory and Design
Concentration Contributions

Source Category 2001
Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 213.4 3.99 1.46

Native Desert 2.1 0.04 0.01

Unstable 206.0 3.85 1.41

Stabilized 5.3 0.10 0.04

Construction 302.7 5.66 2.06

Wind Erosion 109.8 2.05 0.75

Construction Activities 186.6 3.49 1.27

Track Out 7.9 0.15 0.05 Unpaved Road Dust 1.8 0.03 0.01

Paved Road Dust 4,789 89.50 32.67

Vehicles

PM 10 35.9 0.67 0.24

SOx 51.9 - - NOx 2,262.3 - - Stationary Sources

PM 10 6.3 0.12 0.04

SOx 1.6 - -

NOx 55.2 - - Background* 16.5

TOTAL

PM 10 5,350.7 53
SOx 53.5 NOx 2,317.5

*Background includes 13 μ g/m 3 annual average concentration meas ured at the Jean monitoring

station and 3.5 μ g/m 3 of secondary particulate.5-9 Table 5-3

2001 24-Hour BLM Disposal Area Uncontrolled PM 10 Emissions, Percent Contribution, and Concentration

SOURCES PM 10 (tons/day) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 ) Stationary Point Sources
Sand & Gravel O p erations 1.72 0.24 0.65
Utilities

– Natural Gas 0.55 0.08 0.20
As p halt Concrete Manufacture 0.47 0.07 0.18
Industrial Processes 0.22 0.03 0.08
Other Sources 0.34 0.05 0.13
Total 3.29 0.46 1.24 Stationary Area Sources
Small Point Sources 0.50 0.07 0.19
Residential Firewood 0.96 0.13 0.36
Residential Natural Gas 0.22 0.03 0.08
Commercial Natural Gas 0.09 0.01 0.03
Industrial Natural Gas 0.04 0.01 0.01
NG – Purchased at the Source – Carried by SWG 0.58 0.08 0.22
Structural / Vehicle Fires / Wild Fires 0.06 0.01 0.02
Charbroilin g / Meat Cookin g 2.44 0.34 0.92
Disturbed Vacant Lands / Unpaved Parking Lots 253 35.15 95.08
Native Desert Fu g itive Dust 0.00 0.00 0.00
Stabilized Vacant Lan ds Dust 28.00 3.89 10.52
Construction Activit y Fu g itive Dust 63.31 8.80 23.79
Windblown Construction Dust 140.53 19.52 52.81
Total 489.72 68.04 184.04
Nonroad Mobile Sources

Air p ort Su pp ort E q ui p ment 0.12 0.02 0.05
Commercial E q ui p ment 0.00 0.00 0.00
Const r uction & Minin g E q ui p ment 1.17 0.16 0.44
Lawn & Garden E q ui p ment 0.04 0.01 0.02
Railroad E q ui p ment 0.05 0.01 0.02
Recreational E q ui p ment 0.00 0.00 0.00
McCarran International Air p ort 0.81 0.11 0.31
Henderson Executive Air p ort 0.02 0.00 0.01
North Las Ve g as Munici p al Air p ort 0.07 0.01 0.03
Nellis Air Force Base 0.09 0.01 0.03
Total 2.38 0.33 0.89
Onroad Mobile Sources Paved Road Dust (Includes C onstruction Track Out) 150.70 20.94 56.63

Un p aved Road Dust 51.87 7.21 19.49
Hi g hwa y Construction Pro j ects Activities 7.62 1.06 2.86 Highway Construction Projects – Wind Erosion 11.20 1.56 4.21
Vehicular Sulfate PM 1.34 0.19 0.50
Vehicular Tire Wea r 0.27 0.04 0.10
Vehicular Brake Wea r 0.45 0.06 0.17
Vehicular Exhaust 0.95 0.13 0.36
Total 224.40 31.18 84.33 Background* 10.5

Total 719.78 100.00% 281

* Background includes 7 μ g/m 3 24-hour concentration measured at the Boulder City monitoring station on December 21, 1998, and 3.5 μ g/m 3 of secondary particulate.5-10 Table 5-4

Craig Road 24-Hour Uncontrolled Emissions Inventory and Design
Concentration Contributions *

Source Category Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 4.82 30.79 69.74

Native Desert - - -

Unstable 4.32 27.60 62.51

Stabilized 0.50 3.19 7.23

Construction 3.43 21.91 49.63

Wind Erosion 2.72 17.38 39.36

Construction Activities 0.68 4.34 9.84

Track Out 0.03 0.19 0.43 Unpaved Road Dust 0.14 0.89 2.03

Paved Road Dust 3.98 25.42 57.59 Unpaved Parking 0.514 3.28 7.44

Wind Erosion 0.51 3.26 7.38

Vehicles 0.004 0.03 0.06

Race Tracks 2.43 15.52 35.16

Wind Erosion 1.71 10.92 24.74

Vehicles 0.72 4.60 10.42

Vehicles

PM 10 0.1 0.64 1.45

SOx 0.05 - -

NOx 2.36 - - Stationary Sources

PM 10 0.24 1.53 3.47

SOx 0.0004 - -

NOx 0.0583 - - Background** 27.5

TOTAL

PM 10 15.65 254
SOx 0.0504
NOx 2.418

*This inventory was prepared to represent the sour ces within two kilometers of the Craig Road monitoring station on the design day at this site . The relative contribution is based upon the design value of 254 μ g/m 3 . The inventory is considered to be representative of areas with the highest recorded PM 10 values.

**Background includes 24 μ g/m 3 24-hour concentration measured at the Jean monitoring station on January 20, 1999, and 3.5 μ g/m 3 of secondary particulate.5-11 Table 5-5

East Flamingo 24-Hour Uncontrolle d Emissions Inventory and Design
Concentration Contributions *

Source Category Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 2.912 24.38 36.70

Native Desert 0.141 1.18 1.78

Unstable 2.68 22.44 33.77

Stabilized 0.091 0.76 1.15

Construction 3.92 32.83 49.40

Wind Erosion 3.56 29.81 44.87

Construction Activities 0.32 2.68 4.03

Track Out 0.04 0.33 0.50 Unpaved Road Dust 0.01 0.08 0.13

Paved Road Dust 4.96 41.53 62.51

Vehicles

PM 10 0.13 1.09 1.64

SOx 0.06 - -

NOx 3.22 - - Stationary Sources

PM 10 0.01 0.08 0.13

SOx 0.001 - -

NOx 0.14 - - Background** 38.5

TOTAL

PM 10 11.942 189
SOx 0.061
NOx 3.36

*This inventory was prepared to represent the sour ces within two kilometers of the East Flamingo monitoring station on the design day at this site . The relative contribution is based upon the design value of 189 μ g/m 3 . The inventory is considered to be representative of areas with the highest recorded PM 10 values.

**Background includes 35 μ g/m 3 24-hour concentration measured at the Jean monitoring station on March 30, 1999, and 3.5 μ g/m 3 of secondary particulate.5-12 Table 5-6

Green Valley 24-Hour Uncontrolle d Emissions Inventory and Design
Concentration Contributions *

Source Category Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 7.33 21.83 57.09

Native Desert - - -

Unstable 7.29 21.71 56.78

Stabilized 0.04 0.12 0.31

Construction 21.19 63.11 165.03

Wind Erosion 18.3 54.50 142.52

Construction Activities 2.85 8.49 22.20

Track Out 0.04 0.12 0.31 Unpaved Road Dust 0.017 0.05 0.13

Paved Road Dust 3.54 10.54 27.57

Race Tracks 1.26 3.75 9.81

Wind Erosion 1.08 3.22 8.41

Vehicles 0.18 0.54 1.40

Vehicles

PM 10 0.07 0.21 0.55

SOx 0.03 - -

NOx 1.64 - - Stationary Sources

PM 10 0.17 0.51 1.32

SOx 0.19 - -

NOx 0.02 - - Background** 19.5

TOTAL

PM 10 33.577 281
Sox 0.22
Nox 1.66

* This inventory was prepared to represent the sour ces within two kilometers of the Green Valley monitoring station on the design day at this site . The relative contribution is based upon the design value of 281 μ g/m 3 . The inventory is considered to be representative of areas with the highest recorded PM 10 values.

* * Background includes 16 μ g/m 3 24-hour concentration measured at the Jean monitoring station on February 25, 1999, and 3.5 μ g/m 3 of secondary particulate.5-13 Table 5-7

J. D. Smith 24-Hour Uncontrolled Emissions Inventory and Design
Concentration Contributions *

Source Category Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 10.08 36.56 63.06

Native Desert 0.63 2.28 3.94

Unstable 9.4 34.09 58.81

Stabilized 0.05 0.18 0.31

Construction 5.52 20.02 34.53

Wind Erosion 5.1 18.50 31.91

Construction Activities 0.35 1.27 2.19

Track Out 0.07 0.25 0.44 Unpaved Road Dust 0.004 0.01 0.03

Paved Road Dust 11.63 42.18 72.76

Vehicles

PM 10 0.26 0.94 1.63

SOx 0.13 - -

NOx 6.6 - - Stationary Sources

PM 10 0.08 0.29 0.50

SOx 0.002 - -

NOx 0.12 - - Background** 45.5

TOTAL

PM 10 27.574 218
Sox 0.132
Nox 6.72

*This inventory was prepared to represent the sour ces within two kilometers of the J. D. Smith monitoring station on the design day at this site . The relative contribution is based upon the design value of 218 μ g/m 3 . The inventory is considered to be representative of areas with the highest recorded PM 10 values.

** Background includes 42 μ g/m 3 24-hour concentration measured at the Walter Johnson monitoring station on March 31, 1999, and 3.5 μ g/m 3 of secondary particulate.5-14 Table 5-8

Pittman 24-Hour Uncontrolled Em issions Inventory and Design
Concentration Contributions *

Source Category Emissions (tons) Percent
Contribution Impact on Design
Concentration ( μ g/m 3 )

Vacant Land 13.16 67.07 134.48

Native Desert - - -

Unstable 12.9 65.75 131.83

Stabilized 0.26 1.33 2.66

Construction 1.32 6.73 13.49

Wind Erosion 1.12 5.71 11.45

Construction Activities 0.19 0.97 1.94

Track Out 0.01 0.05 0.10 Unpaved Road Dust 0.66 3.36 6.74

Paved Road Dust 2.92 14.88 29.84 Unpaved Parking 1.14 5.81 11.65

Wind Erosion 1.11 5.66 11.34

Vehicles 0.03 0.15 0.31

Vehicles

PM 10 0.06 0.31 0.61

SOx 0.03 - -

NOx 1.51 - - Stationary Sources

PM 10 0.36 1.83 3.68

SOx 0.02 - -

NOx 0.19 - - Background** 38.5

TOTAL

PM 10 19.62 239
Sox 0.05
Nox 1.7

*This inventory was prepared to represent the sources within two kilometers of the Pittman monitoring station on the design day at this site . The relative contribution is based upon the design value of 239 μ g/m 3 . The inventory is considered to be representative of areas with the highest recorded PM 10 values.

** Background includes 35 μ g/m 3 24-hour concentration measured at the Jean monitoring station on March 30, 1999, and 3.5 μ g/m 3 of secondary particulate.5-15 5.4 PM 10 EMISSION LEVELS FOR ATTAINMENT OF THE NAAQS

In order to attain the annual standard by December 31, 2001, the projected annual design value (53

μ g/m 3 ) depicted in Tables 5-1 and 5-2 would need to be reduced by 5.66 percent, for a total reduction

of 3 μ g/m 3 . Because there are five representative sites and a valley-wide emissions inventory, there are six 24-hour design values. The relative impact
from sources differs bas ed upon the individual site parameters or valley-wide characteristic. For example, paved road dust contributes over 42 percent of the total emissions for the J. D. Smith micro-scale area and only about 11 percent to the emissions surrounding the Green Valley monitoring

station. As shown in Table 5-9, the percent reduction to attain the 24-hour NAAQS (150 μ g/m 3 ) varies among the sites chosen by between 20.6 and 46.6 percent, for a total reduction of between

39 and 131 μ g/m 3

.

The background concentration for the annual design year was determined by comparing the
annual concentrations meas ured in 1998 at the 16 monitoring stations within and near the nonattainment area (see Figure 2-1). The lowest measured annual average concentration was considered background. The location of the monitoring station with the lowest annual average
was reviewed to ensure the monitor was located generally upwind of the nona ttainment area. The lowest annual average concentration was measured at the Jean site, which is located
southeast of the nonattainment area. As predominant winds are from the southeast (Figures 2-4 through 2-6), the annual average concentration

of 13 μ g/m 3 was used for the ambient background
for the annual inventories.

A similar process was used to determine the ambient background concent ration for the 24-hour design days. The PM 10 concentration measured at each of the Clark County Air Quality Division (AQD) monitoring stations for each of the design days was

reviewed to determine t he lowest measured Annual Emissions
Levels Determined by Percent Reduction Required

at J. D. Smith Site5-16 concentration in the area. When the lowest concentration had been determined, the wind roses for the design day (Appendix D) were reviewed to

ensure the minimum measurement had occurred at a station upwind of each of the representative stations. The ambient background concentrations are listed for each 24-hour inventory in Tables 5-3 through 5-8.

Background concentrations are assumed to be consistent or unchanging fr om year to year and are not subject or amenable to c ontrol strategies. This
is due to the fact that background sources are mostly natural PM 10 sources that ar e not within the ability of the SIP to cont rol. An example would be wind-blown dust from parcels of native desert not within the BLM disposal area. Consequently,
control measures and/or reductions are limited to
man-made PM 10 emission sources. Fortunately,
reduction in man-made sources of PM 10 will allow
the area to attain the st andards. Accordingly, manmade influences on the annual design concentrations must be reduced 8.2 percent. The
reduction from man-m ade sources for the
attainment of the 24-h our standard varies between 25.9 and 48.4 percent, as shown in Table 5-9. The higher reductions from man-made sources are necessary since almost 25 percent of the annual emissions and up to 19.2 percent of the daily
emissions in 2001 are uncontro llable (natural). The proportional rollback method allows the
establishment of emissi on levels to demonstrate attainment for all design values: annual, 24-hour micro-scale, and 24-hour valley-wide. Regional Background
Concentrations

Assumed to be
Constant5-17 Table 5-9

24-Hour Attainment Percent and Concentration Reductions

Location Design
Value ( μ g/m 3 ) Percent
Reduction for

Attainment Concentration
Reduction for Attainment ( μ g/m 3 ) Percent Reduction
From Man-made
Sources Valley-wide 281 46.6 131 48.4 Craig Road 254 40.9 104 45.9

East Flamingo 189 20.6 39 25.9

Green Valley 281 46.6 131 50.1

J. D. Smith 218 31.2 68 39.4

Pittman 239 37.2 89 44.4

5.4.1 Annual Attainment Levels

Table 5-1 depicts a pr ojected 2001 valley-wide emission inventory of 170,625 tons of PM 10 . A reduction of 5.66 percent, or 9,657 tons, is needed

to attain the annual standard of 50 μ g/m 3 . The

PM 10 emissions allowed dur ing calendar year 2001 on a valley-wide basis without exceeding the
annual standard would be 160,968 tons for all sources including background conditions, or 156,634 tons for man-made sources applying the proportional relationshi p between valley-wide emissions and the projec ted design concentration as previously described.

The annual emission inventor y for 2001 for the J. D. Smith micro-inventory area depicted in Table 5-2 is 5,351 tons of PM 10 . A reduction of 5.66 percent, or 303 tons, is needed to attain the annual standard of

50 μ g/m 3 . The estimated amount of PM 10 that can be emitted during calendar year 2001 within the micro-inventory area wit hout an exceedance of the 24-hour NAAQS would be 5,048 tons for all sources including background conditi ons, or 4,912 tons for

man-made sources.5-18 5.4.2 24-Hour Attainment Levels

Table 5-10 depicts the proj ected 24-hour attainment levels for the valley and the five micro-scale sites in 2001. The reduction percentages presented in Table 5-9 are applied to the appropriate source categories, and the reduction of tons of PM 10 emitted for each location ar e also presented. Table 5-10 expresses the same information as Table 5-9 in terms of tons/day rather than percentages. The estimated number of tons emitted on the design day is summarized in the second column of the table. The reduction in emissions required to
demonstrate attainment from all sources is

summarized in the third colu mn. The fourth column presents the reduction fr om man-made sources to reach attainment, and the last column presents the tons/day that may be emitt ed and attainment of the
24-hour NAAQS established. The estimated emissions after implement ation of the control

measures cannot exceed the values in the last
column at each location for a successful attainment

demonstration. 24-Hour Attainment Levels Vary by Site

Table 5-10

24-Hour PM 10 Attainment Levels by Location

Location Design Day
Emission Inventory

(tons) Reduction to
Meet 24-Hour NAAQS

(tons) Reduction
from Manmade Sources

to Meet 24- Hour NAAQS (tons) 24-Hour
Attainment
Levels to Meet NAAQS

(tons)

Valley-wide 719.78 335.42 348.37 371.41 Craig Road 15.65 6.40 7.18 8.47 East Flamingo 11.94 2.46 3.09 8.85 Green Valley 33. 58 15.65 16.82 16.76

J. D. Smith 27. 57 8.60 10.86 16.71

Pittman 19.62 7.30 8.71 10.915-19 5.5 ATTAINMENT DEMONSTRATIONS

Chapter 4 noted the contro l initiatives implemented since the 1998 base year. These initiatives are projected to reduce PM 10 emissions from disturbed vacant land, construction, paved roads, unpaved roads, unpaved parking lots, and race tracks. The predicted emissions with the proposed control
initiatives are the basis for the attainment
demonstrations. Calculations for controlled inventories are pres ented in Appendix L.

5.5.1 Annual Attainment Demonstration in 2001

The valley-wide annual emi ssions inventory with control measure reductions as applied to the J. D. Smith micro-scale inventory and corresponding

PM 10 concentration is depicted in Table 5-11. The reductions correspond to an overall decrease of 31,942 tons, enough to demonstrate attainment by a wide margin. Since there is a proportional relationship between emissions and concentrations, these valley-wide emissi on reductions are also expected to reduce the annual concentration by

7 μ g/m 3 to 46 μ g/m 3 , depending on the location.

As shown in Table 5-11, these reductions are adequate to reach attain ment of the annual

standard of 50 μ g/m 3 . The anticipated ambient

concentration of 46 μ g/m 3 is below the ambient standard and even with a small degree of uncertainty regarding the in ventory, the attainment
demonstration is sound. T he attainment levels in
Table 5-11 are not intended to be source specific. Specifically, the individual stationary sources may vary over time, or the ex act number of acres that

are vacant or under constr uction may vary. Despite
small variations in indi vidual sources, the total valley-wide emissions are anticipated to remain at or below the projections shown in Table 5-11. With SIP Adopted Controls, the Annual

Concentration Will
Be Reduced to 46.1

μ g/m 35-20 Table 5-11

2001 Annual BLM Disposal Area Controlled PM 10 Emissions and Attainment
Concentration Contributions

SOURCES PM 10 (TPY) Controlled

PM 10 (TPY) Percent
Reduction Impact on
Attainment
Concentration ( μ g/m 3 ) Stationary Point Sources
Sand & Gravel O p erations 627 627 0.00 0.13
Utilities

– Natural Gas 199 199 0.00 0.04
As p halt Concrete Manufacture 171 171 0.00 0.04
Industrial Processes 80 80 0.00 0.02
Other Sources 124 124 0.00 0.03 Total 1,201 1,201 0.00 0.26 Stationary Area Sources
Small Point Sources 184 184 0.00 0.04
Residential Firewood 89 89 0.00 0.02
Residential Natural Gas 79 79 0.00 0.02
Commercial Natural Gas 33.2 33.2 0.00 0.01
Industrial Natural Gas 14 14 0.00 0.00
NG – Purchased at the Source – Carried by SWG 210 210 0.00 0.04
Structural / Vehicle Fires / Wild Fires 20 20 0.00 0.00
Charbroilin g / Meat Cookin g 889 889 0.00 0.19 Disturbed Vacant Lands / Unpaved Parking Lots 33,100 21,184 -36.00 4.53
Native Desert Fu g itive Dust 9, 520 9,520 0.00 2.04
Stabilized Vacant Lands Dust 3,640 3,640 0.00 0.78
Construction Activit y Fu g itive Dust 23,10 9 15,252 -34.00 3.26
Windblown Construction Dust 18,381 11,861 -35.47 2.54 Total 89,269 62,976 -30.23 13.47
Nonroad Mobile Sources

Air p ort Su pp ort E q ui p ment 44 44 0.00 0.01
Commercial E q ui p ment 0.3 0.3 0.00 0.00
Construction & Minin g E q ui p ment 428 428 0.00 0.09
Lawn & Garden E q ui p ment 15 15 0.00 0.00
Railroad E q ui p ment 17 17 0.00 0.00
Recreational E q ui p ment 1.0 1.0 0.00 0.00
McCarran International Air p ort 297 297 0.00 0.06
Henderson Executive Air p ort 7 7 0.00 0.00
North Las Ve g as Munici p al Air p ort 27 27 0.00 0.01
Nellis Air Force Base 31.9 31.9 0.00 0.01
Total 867 867 0.00 0.19
Onroad Mobile Sources Paved Road Dust (Includes Constr uction Track Out) 55,005 50,822 -7.61 10.87

Un p aved Road Dust 18,93 2 18,932 0.00 4.05
Hi g hwa y Construction Pro j ects Activities 2,782 1,836 -34.00 0.39 Highway Construction Projects – Wind Erosion 1,470 951 -35.29 0.20
Vehicular Sulfate PM 489 489 0.00 0.10
Vehicular Tire Wea r 100 100 0.00 0.02
Vehicular Brake Wea r 163 163 0.00 0.03
Vehicular Exhaust 346 346 0.00 0.07 Total 79,287 73,638 -7.12 15.75 Background 16.5

Total 170,625 138,683 -18.95 46.205-21 As the only monitoring stat ion where violations of
the annual NAAQS have o ccurred, an attainment
demonstration was conducted using the J. D. Smith micro-scale inventory. As depicted in Table 5-12,
the micro-scale emissions are reduced by over 12 percent. Since there is a proportional relationship between emissions and concentrations, these emission reductions are also expected to reduce the annual concentration by almost 5 μ g/m 3

, with a projected 2001 ambient concentration of

48.5 μ g/m 3 . The projected value, with SIP PM 10 controls implemented, is below the national annual
standard. Even with some uncertainty regarding the emissions inventory, the attainment
demonstration is conservative in that there is a margin between the N AAQS and the projected attainment year concentration.

5.5.2 24-Hour Attainment Demonstration in 2006

Chapter 4 noted that cont rol measures recently adopted as part of this SIP are projected to reduce

PM 10 from vacant land, construction sites, unpaved parking, race tracks, and paved road dust. Most of

the control measures wil l be fully implemented by
the end of 2003. These c ontrols were applied to the 2001 projected 24-hour emission inventory for the BLM disposal area. As presented in Table 5-13, the controls as par tially implemented in 2001
will not reduce emissions to a level below the
24-hour NAAQS. Therefor e, an extension of the
attainment date for the 24-hour NAAQS is being requested. This request is presented in Chapter 7
of the SIP. The extens ion is being requested to 2006. Most of the controls will be in place by the end of 2003, reducing emissions below the 24-hour NAAQS for three years ending in 2006. The 2006 24-hour BLM disposal ar ea inventory with SIPadopted controls fully impl emented is presented in Table 5-14. The controls were also applied to all
five of the micro-scale inventories for the areas surrounding the five monitoring stations where
exceedances of the national 24-hour standard were

recorded. With Fully Adopted
Controls 24-Hour
Attainment Can Be

Reached at All
Micro-Scale Sites and Valley-Wide5-22 Table 5-12

J. D. Smith 2006 Annual Controlled Em issions Inventory and Attainment
Concentration Contributions

Source Category Uncontrolled
2006
Emissions

(tons) Controlled
2006
Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration ( μ g/m 3 )

Vacant Land 213.4 139.3 -34.7 0.95

Native Desert 2.1 2.1 0.00 0.01

Unstable 206.0 131.8 -36.00 0.90

Stabilized 5.3 5.3 0.00 0.04

Construction 302.7 201.3 -33.50 1.37

Wind Erosion 109.8 71.1 -36.00 0.48

Construction

Activities 186.6 123.2 -34.00 0.84

Track Out 7.9 7.1 -11.00 0.05 Unpaved Road
Dust 1.8 1.8 0.00 0.01

Paved Road Dust 4,789 4,311 -10.00 29.41

Vehicles

PM 10 35.9 35.9 0.00 0.24

SOx 51.9 51.9 - - NOx 2,262 2,262 - - Stationary
Sources

PM 10 6.3 6.3 0.00 0.04

SOx 1.6 1.6 - -

NOx 55.2 55.2 - - Background 16.5

TOTAL

PM 10 5,350.7 4,695.5 -12.25 48.5
SOx 53.5 NOx 2,317.5

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.5-23 Table 5-13

2001 24-Hour BLM Disposal Area Controlled PM 10 Emissions and Ambient
Concentration Contributions

SOURCES PM 10 (TPD) Controlled

PM 10 (TPD) Percent
Reduction Impact on
Ambient
Concentration ( μ g/m 3 ) Stationary Point Sources
Sand & Gravel O p erations 1.72 1.72 0.00 0.65
Utilities

– Natural Gas 0.55 0.55 0.00 0.20
As p halt Concrete Manufactu re 0.47 0.47 0.00 0.18
Industrial Proce sses 0.22 0.22 0.00 0.08
Other Sources 0.34 0.34 0.00 0.13
Total 3.29 3.29 0.00 1.24 Stationary Area Sources
Small Point Sources 0.50 0.50 0.00 0.19
Residential Firewood 0.96 0.96 0.00 0.36
Residential Natural Gas 0.22 0.22 0.00 0.08
Commercial Natural Gas 0.09 0.09 0.00 0.03

Industrial Natural Gas 0.04 0.04 0.00 0.01
NG – Purchased at the Source – Carried by SWG 0.58 0.58 0.00 0.22
Structural / Vehicle Fires / Wild Fires 0.06 0.06 0.00 0.02 Charbroiling / Meat Cooking 2.44 2.44 0.00 0.92 Disturbed Vacant Lands / Unpav ed Parking Lots 253 161.92 -36.00 60.85 Native Desert Fugitive Dust 0.00 0.00 0.00 0.00
Stabilized Vacant Lands Dust 28.00 28.00 0.00 10.52 Construction Activity Fugi tive Dust 63.31 41.79 -34.00 15.70
Windblown Construction Dust 140.53 90. 69 -35.00 34.06
Total 489.72 327.27 -33.00 122.99

Nonroad Mobile Source s Air p ort Su pp ort E q ui p ment 0.12 0.12 0.00 0.05
Commercial E q ui p ment 0.00 0. 00 0.00 0.00
Construction & Minin g E q ui p ment 1.17 1. 17 0.00 0.44
Lawn & Garden E q ui p ment 0.04 0.04 0.00 0.02
Railroad E q ui p ment 0.05 0.05 0.00 0.02
Rec r eational E q ui p ment 0.00 0. 00 0.00 0.00
McCarran International Air p ort 0.81 0.81 0.00 0.31
Henderson Executive Air p ort 0.02 0.02 0.00 0.01
North Las Ve g as Munici p al Air p ort 0.07 0.07 0.00 0.03
Nellis Air Force Base 0.09 0.09 0.00 0.03
Total 2.38 2.38 0.00 0.89
Onroad Mobile Sources Paved Road Dust (Includes Constr uction Track Out) 150.70 139.35 -7.53 52.37

Un p aved Road Dust 51. 87 40.69 -21.55 15.29
Hi g hwa y Construction Pro j ects Activities 7.62 5.03 -34.00 1.89 Highway Construction Projects – Wind Erosion 11. 20 7.27 -35.09 2.73
Vehicular Sulfate PM 1.34 1.34 0.00 0.50
Vehicular Tire Wea r 0.27 0.27 0.00 0.10
Vehicular Brake Wea r 0.45 0.45 0.00 0.17
Vehicular Exhaust 0.95 0.95 0.00 0.36
Total 224.40 195.31 -12.91 73.41 Background 10.5

Total 719.78 528.29 -26.53 209.045-24 Table 5-14

2006 24-Hour BLM Disposal Area Controlled PM 10 Emissions and
Attainment Concentration Contributions

SOURCES PM 10 (TPD) Controlled

PM 10 (TPD) Percent
Reduction Impact on
Attainment
Concentration ( μ g/m 3 ) Stationary Point Sources
Sand & Gravel O p erations 1.72 1.72 0.00 1.18
Utilities

– Natural Gas 0.55 0.55 0.00 0.37
As p halt Concrete Manufactu re 0.47 0.47 0.00 0.32
Industrial Proce sses 0.22 0.22 0.00 0.15
Other Sources 0.34 0.34 0.00 0.23
Total 3.29 3.29 0.00 2.25 Stationary Area Sources
Small Point Sources 0.50 0.50 0.00 0.35
Residential Firewood 1.12 1.12 0.00 0.77
Residential Natural Gas 0.25 0.25 0.00 0.17
Commercial Natural Gas 0.09 0.09 0.00 0.06
Industrial Natural Gas 0.04 0.04 0.00 0.03
NG – Purchased at the Source – Carried by SWG 0.58 0.58 0.00 0.39
Structural / Vehicle Fires / Wild Fires 0.07 0.07 0.00 0.04 Charbroiling / Meat Cooking 2.84 2.84 0.00 1.94 Disturbed Vacant Lands / Unpav ed Parking Lots 19. 30 5.40 -72.00 3.70 Native Desert Fugitive Dust 0.00 0.00 0.00 0.00
Stabilized Vacant Lands Dust 1.09 1.09 0.00 0.75
Construction Activit y Fu g itive Dust 40.70 13.02 -68.00 8.93
Windblown Construction Dust 90.34 27. 20 -69.89 18.64
Total 156.91 52.00 -66.73 35.77
Nonroad Mobile Sources

Air p ort Su pp ort E q ui p ment 0.14 0.14 0.00 0.10
Commercial E q ui p ment 0.00 0. 00 0.00 0.00
Construction & Minin g E q ui p ment 1.36 1. 36 0.00 0.94
Lawn & Garden E q ui p ment 0.05 0.05 0.00 0.03
Railroad E q ui p ment 0.05 0.05 0.00 0.04
Recreational E q ui p ment 0.00 0. 00 0.00 0.00
McCarran International Air p ort 0.57 0.57 0.00 0.39
Henderson Executive Air p ort 0.02 0.02 0.00 0.01
North Las Ve g as Munici p al Air p ort 0.07 0.07 0.00 0.05
Nellis Air Force Base 0.09 0.09 0.00 0.06
Total 2.36 2.36 0.00 1.62
Onroad Mobile Sources Paved Road Dust (Includes Constr uction Track Out) 161.70 114.86 -28.97 78.71 Unpaved Road Dust 55.11 19.50 -64.61 13.36 Highway Construction Projects Activities 4.90 1.57 -68.00 1.07 Highway Construction Projects – Wind Erosion 7. 20 2.22 -69.17 1.52
Vehicular Sulfat e PM 1.52 1.52 0.00 1.04
Vehicular Tire Wear 0.32 0.32 0.00 0.22
Vehicular Brake Wear 0.51 0.51 0.00 0.35
Vehicular Exhaust 0.91 0.91 0.00 0.62
Total 232.16 141.40 -39.09 96.90 Background 10.5

Total 394.72 199.25 -49.52 147.045-25Applying the proportional relationship, the valleywide 24-hour concentration impacts are reduced by over 60 percent (67.93 μ g/m 3 ) due to construction

emission reductions an d 28.97 percent (32.1 μ g/m 3 ) due to paved street network PM 10 reductions. In
addition to the other c ontrol measures, these reductions equal an overall decrease in the 24-hour predicted concentration of 134 μ g/m 3 as shown in
Table 5-14. The overall reduction is almost 50 percent, and the predicted am bient concentration of

147.04 μ g/m 3 is sufficiently below the national 24-

hour standard of 150 μ g/m 3 to clearly demonstrate
attainment. Additional reductions in the future are anticipated from federal mob ile source rulemaking.
Reductions from federal rules were not factored into
the SIP.

The reductions described in Chapter 4 were also applied to the five representative micro-scale inventories surrounding the five ambient monitoring

sites where violations of the 24-hour national

standard were measured. The sources in the
micro-scale inventories varied as well as their relative contributions, due in part to meteorology
and the amount of construc tion in the areas. The reductions and the predict ed impacts are depicted for each site in Tables 5-15 through 5-19.

The overall percent reduction at each of the sites ranged from 47.68 to 64.92. The predicted ambient impacts after controls were well below the national

24-hour standard of 150 μ g/m 3 . The 2006 controlled concentrations ranged from 111.23

μ g/m 3 to 134.03 μ g/m 3 , allowing sufficient margin to

demonstrate attainment at each site. The
attainment demonstration at the five representative sites shows that as growth continues in the nonattainment area, th e SIP-adopted control

measures will reduce PM 10 concentrations at other
sites where PM 10 sources are present. 24-Hour Valley-Wide
Concentration of

147.04 μ g/m 3 in 2006

Overall Percent
Reduction for MicroScale Inventories Ranged from
48 to 655-26 Table 5-15

Craig Road 24-Hour Emissions Inventory and Attainment Concentration
Contributions

Source Category Uncontrolled
Emissions (tons) Controlled

Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration **
( μ g/m 3 )

Vacant Land 4.82 1.71 -65.00 24.74

Native Desert - - - -

Unstable 4.32 1.21 -72.00 17.50

Stabilized 0.50 0.50 0.00 7.23

Construction 3.43 1.03 -70.00 14.90

Wind Erosion 2.72 0.79 -71.00 11.41

Construction

Activities 0.68 0.22 -68.00 3.15

Track Out 0.03 0.02 -22.00 0.34 Unpaved Road Dust 0.14 0.14 0.00 2.03

Paved Road Dust 3.98 2.71 -32.00 39.21 Unpaved Parking 0.514 0.14 -72.00 2.10

Wind Erosion 0.51 0.14 -72.00 2.07

Vehicles 0.004 0.00 -48.00 0.03

Race Tracks 2.43 0.63 -74.00 9.12

Wind Erosion 1.71 0.48 -72.00 6.93

Vehicles 0.72 0.15 -79.00 2.19

Vehicles

PM 10 0.1 0.10 0.00 1.45

SOx 0.05 0.05 - -

NOx 2.36 2.36 - - Stationary Sources

PM 10 0.24 0.24 0.00 3.47

SOx 0.0004 0.0004 - -

NOx 0.0583 0.0583 - - Background 27.5

TOTAL

PM 10 15.65 6.70 -57.17 124.50
SOx 0.0504 0.0504
NOx 2.418 2.418

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.

** After implementation of control measures adopted as part of this SIP.5-27 Table 5-16

East Flamingo 24-Hour Emissions Inven tory and Attainment Concentration
Contributions

Source Category Uncontrolled
Emissions (tons) Controlled

Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration **
( μ g/m 3 )

Vacant Land 2.912 0.98 -66.26 12.38

Native Desert 0.141 0.14 0.00 1.78

Unstable 2.68 0.75 -72.00 9.46

Stabilized 0.091 0.09 0.00 1.15

Construction 3.92 1.17 -70.26 14.69

Wind Erosion 3.56 1.03 -71.00 13.01

Construction

Activities 0.32 0.10 -68.00 1.29

Track Out 0.04 0.03 -22.00 0.39 Unpaved Road
Dust 0.01 0.01 0.00 0.13

Paved Road Dust 4.96 3.95 -20.36 49.78

Vehicles

PM 10 0.13 0.13 0.00 1.64

SOx 0.06 0.06 - -

NOx 3.22 3.22 - - Stationary
Sources

PM 10 0.01 0.01 0.00 0.13

SOx 0.001 0.001 - -

NOx 0.14 0.14 - - Background 38.5

TOTAL

PM 10 11.942 6.248 -47.68 117.25
SOx 0.061 0.061
NOx 3.36 3.36

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.

** After implementation of control meas ures adopted as part of this SIP.5-28 Table 5-17

Green Valley 24-Hour Emissions Inven tory and Attainment Concentration
Contributions

Source Category Uncontrolled
Emissions (tons) Controlled

Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration **
( μ g/m 3 )

Vacant Land 7.33 2.08 -71.61 16.21

Native Desert - - - -

Unstable 7.29 2.04 -72.00 15.90

Stabilized 0.04 0.04 0.00 0.31

Construction 21.19 6.25 -70.50 48.68

Wind Erosion 18.3 5.31 -71.00 41.33

Construction

Activities 2.85 0.91 -68.00 7.10

Track Out 0.04 0.03 -22.00 0.24 Unpaved Road
Dust 0.017 0.02 0.00 0.13

Paved Road
Dust 3.54 2.85 -19.49 22.20

Race Tracks 1.26 0.34 -73.00 2.65

Wind Erosion 1.08 0.30 -72.00 2.36

Vehicles 0.18 0.04 -79.00 0.29

Vehicles

PM 10 0.07 0.07 0.00 0.55
SOx 0.03 0.03 - -

NOx 1.64 1.64 - - Stationary
Sources

PM 10 0.17 0.17 0.00 1.32

SOx 0.19 0.19 - -

NOx 0.02 0.02 - - Background 19.5

TOTAL

PM 10 33.577 11.779 -64.92 111.23
SOx 0.22 0.22
NOx 1.66 1.66

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.

** After implementation of control meas ures adopted as part of this SIP.5-29 Table 5-18

J. D. Smith 24-Hour Emissions Inven tory and Attainment Concentration
Contributions

Source Category Uncontrolled
Emissions (tons) Controlled

Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration **
( μ g/m 3 )

Vacant Land 10.08 3.31 -67.14 20.72

Native Desert 0.63 0.63 0.00 3.94

Unstable 9.4 2.63 -72.00 16.47

Stabilized 0.05 0.05 0.00 0.31

Construction 5.52 1.65 -70.19 10.29

Wind Erosion 5.1 1.48 -71.00 9.25

Construction

Activities 0.35 0.11 -68.00 0.70

Track Out 0.07 0.05 -22.00 0.34 Unpaved Road Dust 0.004 0.00 0.00 0.03

Paved Road Dust 11.63 8.85 -23.90 55.36

Vehicles

PM 10 0.26 0.26 0.00 1.63

SOx 0.13 0.13 - -

NOx 6.6 6.6 - - Stationary Sources

PM 10 0.08 0.08 0.00 0.50

SOx 0.002 0.002 - -

NOx 0.12 0.12 - - Background 45.5

TOTAL

PM 10 27.574 14.152 -48.68 134.03
SOx 0.132 0.132
NOx 6.72 6.72

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.

** After implementation of control measures adopted as part of this SIP.5-30 Table 5-19

Pittman 24-Hour Emissions Inventory and Attainment Concentration
Contributions

Source Category Uncontrolled
Emissions (tons) Controlled

Emissions (tons) Percent
Reduction * Impact on
Attainment
Concentration **
( μ g/m 3 )

Vacant Land 13.16 3.87 -70.58 39.57

Native Desert - - - -

Unstable 12.9 3.61 -72.00 36.91

Stabilized 0.26 0.26 0.00 2.66

Construction 1.32 .039 -70.20 4.02

Wind Erosion 1.12 0.32 -71.00 3.32

Construction

Activities 0.19 0.06 -68.00 0.62

Track Out 0.01 0.01 -22.00 0.08 Unpaved Road
Dust 0.66 0.66 0.00 6.74

Paved Road Dust 2.92 2.23 -23.63 22.79 Unpaved Parking 1.14 0.33 -71.37 3.34

Wind Erosion 1.11 0.31 -72.00 3.18

Vehicles 0.03 0.02 -48.00 0.16

Vehicles

PM 10 0.06 0.06 0.00 0.61
SOx 0.03 0.03 - -

NOx 1.51 1.51 - - Stationary
Sources

PM 10 0.36 0.36 0.00 3.68

SOx 0.02 0.02 - -

NOx 0.19 0.19 - - Background 38.5

TOTAL

PM 10 19.62 7.9018 -59.73 119.25
SOx 0.05 0.05
NOx 1.7 1.7

* Sources with zero percent reduction may in fa ct have controls in place that are reducing PM 10 emissions. The zero percent figure represen ts the fact that these sources are not being controlled further as part of the SIP commitments.

** After implementation of control meas ures adopted as part of this SIP.5-31 5.6 REASONABLE FURTHER PROGRESS

Part D of the Clean Air Ac t, Section 171, indicates
that the term “Reasonable Further Progress” means
“such annual incremental reductions in emissions of the relevant air pollutant as are required by this part or may be reasonably requir ed by the Administrator for the purpose of ensur ing attainment of the applicable national ambient air quality standard by the applicable date.” The modeling results presented in this chapter support the conclusion that the Clark County N onattainment Area will meet
the PM 10 24-hour standard by the attainment date of December 31, 2006.

According to the General Preamble, the PM 10 nonattainment area SIP must include quantitative milestones which are to be achieved every three years until the area is r edesignated attainment and which demonstrate reasonable further progress (RFP) toward attainment by the applicable date. The quantitative milestones allow progress to be quantified or measured. S pecifically, states should identify and submit quantitative milestones providing for the amount of emission reductions adequate to achieve the NAAQS by the attainment date. Reasonable further progress should be met by showing incremental emission reductions generally sufficient to ma intain linear progress
towards attainment. The milestone achievement dates analyzed in this plan are 2003 and 2006. These milestones have been addressed by quantifying emission reductions which result from the implementation of the committed control measures after predicted growth has occurred.

The emissions in the base case (1998), 2003, and
2006 controlled emission inventories were used to develop the RFP analysis shown in Figure 5-1.
Detailed calculations are presented in Appendix M. The adopted control measures used to calculate
emission reductions were evaluated on a cumulative basis to estimate the total valley-wide emissions for 2003 and 2006. In general, full implementation of the c ontrol measures described in Chapter 4 was assumed. This is consistent with Reasonable Further Progress Report
Due in 20035-32Figure 5-1Reasonable Further Progress Analysis - 24-Hour NAAQS931.95276.48199.25010020030040050060070080090010001998 Base Case 2003 Committed Measures 2006 Committed Measures24 - Hour

PM 10 (Tons)210.7024 - Hour Attainment Level5-33 the implementation schedul es contained in the rules and the Clark County Air Quality Division (AQD) schedules for increasing rule-related activities. See Chapter 4 for a discussion of rule implementation and effectiveness, including schedules of implementation and estimated cost of controls. Details on the emission inventory and rollback calculations are presented in Appendices B, E, and M. The proj ected emission reductions
from the control measures result in daily emissions
of 276.48 tons and 199.25 tons in 2003 and 2006 respectively. The 77.23 tons-per-day reduction in
emissions from 2003 to 2006 satisfies the RFP requirement.

5.7 2006 MOBILE SOURCE EMISSIONS BUDGET

In accordance with the 1990 Clean Air Act Amendments (Amendments), conformity requirements are intended to ensure that transportation activities do not result in air quality degradation. Section 176 of the Amendments requires that transporta tion plans, programs, and projects conform to app licable air quality plans before the transportation action is approved by a Metropolitan Planning Organi zation (MPO). The designated MPO for Clark County is the Regional Transportation Commission as designated by the agreement among general purposes local governments and the Go vernor of Nevada (July 8, 1981).

Section 176(c) provides the framework for ensuring that federal actions conform to air quality plans under Section 110. Conformity to an implementation plan means that proposed activities

must not:

(1) cause or contribute to any new violation or any standard in any area; (2) increase the frequency or severity of any existing violation of any standard in any

area; or (3) delay timely attainment of any standard or any required interim emission reductions or other milestones in any

area. Emissions
Reductions Between the Base Year (1998)
and 2006 Are Anticipated to Show

Reasonable Further Progress5-34 For nonattainment areas required to demonstrate reasonable further progress and attainment, U. S. EPA requires that the St ate Implementation Plan (SIP) contain documentation of the motor vehicle

emissions on which the atta inment demonstration is
based. The amount of mobile source emissions

utilized in the attainment demonstration becomes the “emission budget” for highway and transit vehicles. The transportation plans and programs produced by the transportation planning process are required to result in emissions that are within the budget.

The proportional rollback modeling utilized in this
SIP demonstrates attainm ent of the annual NAAQS
in 2001 and the 24-hour NAAQS in 2006. The mobile source emissions budget will be based upon the annual standard budget until 2003. A reasonable further progress demonstration has been completed for 2003. The mobile source emissions budget for the annual attainment was compared to the reas onable further progress budget for the 24-hour standar d, and the smaller of the two budgets (2003 milestone) will be used for transportation conformity purposes beginning in 2003. The mobile source emissions budget for
attainment of the 24- hour standard has been compared to the mobile source emissions budget
for annual attainment. The smaller of the two budgets will be used for transportation conformity purposes to ensure attainment of both standardsbeginning in 2006. The projections in the valleywide modeling attainment demonstration indicate that with plan implementat ion, the total daily PM 10 emissions in 2001 for all sources in the BLM disposal area would be 528.29 tons per day. Details of the 2006 projections are presented in Appendix E. For confo rmity purposes, the motor vehicle emissions budget includes:

• regional re-entrained du st from travel on paved roads;

• vehicular exhaust;

• vehicular brake wear;

• vehicular tire wear;

• travel on unpaved roads; and

• road construction. The Valley-Wide 24-
Hour Mobile Source

Emissions Budget Will Vary Depending
on the Year5-35 The onroad mobile porti on of the budget, which includes emissions from paved road dust; vehicle exhaust; vehicle brake and tire wear; and travel on unpaved roads is 194.11 tons per day. Total highway construction emissions in 2001 are estimated to be 7.64 tons per day. Together, these emissions comprise the motor vehicle emissions budget for PM 10 of 201.75 tons per day. Since the inventory of emissions from stationary sources participating in the emissi on reduction credit (ERC) program has not been reduced to account for ERC credits, the reduction in em issions from the paving of unpaved roads is a tr ue reduction of emissions into the airshed. For the analysis year 2003, the budget will change to 155.77 tons per day. Beginning in analysis year 2006, the mobile source emissions budget of 141.41 tons per day will be used for transportation conformity purposes. The development of the mobi le source emissions budget is explained in detail in Appendix N.

This budget will be compared to the 2003 RFP budget and the 2006 attain ment budget during future years and adjusted as necessary to ensure
attainment of both the annual and 24-hour PM 10 NAAQS. The lower budget will be used when the
annual and 24-hour mobile source emission budgets differ.

It is important to note t hat no additional conformity budgets are established with respect to the microscale or micro-inventor y modeling. The microinventory analysis addresses attainment of the 24- hour standard at representative monitoring sites only. The U. S. EPA transportation conformity regulations do not require sub-area budgets to be established if the implementation plan estimates future emissions by geographic sub-area of the

nonattainment area. Accord ing to federal statute, (November 24, 1993, F ederal Register, page 62194), the emissions budget applies as a ceiling on emissions in the year for which it is defined, and for all subsequent years. The transportation conformity budget will remain in place until a different budget for another year is defined or until a future SIP revision modifies the budget. The Initial Transportation Conformity Budget
Will Be Set at 201.75 Tons Per Day5-36 5.8 ATTAINMENT DEMONSTRATION SUMMARY

Man-made source categor ies that contribute significantly to the annual design value of 53 μ g/m 3
(defined as greater than one μ g/m 3 ) 1 identified in Table 5-1 are disturbed vacant land, construction activities (including wind erosion), paved road dust,and unpaved roads. Similarly, significant manmade sources contributing to the 24-hour design day values (defined as s ources contributing greater

than five μ g/m 3 ) identified in Tables 5-3 through 5-8 include these sources and unpaved parking and
race tracks.

An attainment demonstration for the annual standard (50 μ g/m 3 ) during the calendar year of 2001 was successful due to the implementation of control measures, developed as part of this SIP, to

control PM 10 from construction activities, wind
erosion from disturbed vac ant land, and silt loading on paved roads. The 24-hour attainment demonstration was similarly successful for high wind days by December 31, 2006 because of the control measures adopted as part of this SIP for

PM 10 . Emissions from significant sources that are not affected by high winds were also controlled to reduce emissions regardless of wind conditions.
These controls will reduce emissions from construction activities, wind erosion from disturbed vacant land, unpaved roads, silt loading on paved roads, and unpaved parking. Race tracks are controlled using the same measures that address disturbed vacant land. Chapter 7 addresses the request for an extension of the
24-hour NAAQS attainment date to 2006. SIP-Adopted Control
Measures for Significant Sources

Are Adequate to
Demonstrate
Attainment of the 24-

Hour and Annual NAAQS for PM 106-1 

## CHAPTER 6: MOST STRINGENT CONTROL
MEASURE ANALYSIS

6.1 INTRODUCTION

The attainment demonstration presented in Chapter 5 concludes that the Annual National Ambient Air Quality
Standard (NAAQS) for PM 10 will be attained by the December 31, 2001 deadline established by the 1990 Clean Air Act Amendments (CAAA). The 24-Hour
NAAQS for PM 10 , however, was found to be not achievable until 2006, and it was determined that an
extension of the deadline would be needed.

Section 188(e) of the CAAA allows U. S. EPA to extend the Serious Area attainment date up to five years upon application of the state if certain requirements are satisfied. Among these are that the Serious Area plan contains the most stringent measures (MSMs) included in any state implementation plan, or achieved in practice in any state, and that can be feasibly implemented in the nonattainment area. The plan must also include a
demonstration of attainment by the most expeditious alternative date practicable but no later than December 31, 2006.

The purpose of this chapter is to provide documentation
that this PM 10 State Implementation Plan (SIP) does include the Most Stringent Measures (MSMs) that are included in the impl ementation plan of any state, or are achieved in practice in any state, and can feasibly be implemented in the Las Vegas Valley nonattainment area. Chapter 7 addresses the formal request for an
extension of the attainm ent date for the 24-hour PM 10 NAAQS from December 31, 2001 to December 31,
2006.

6.2 THE MOST STRINGENT MEASURE REQUIREMENT

To date, U. S. EPA has not issued any policy or regulation interpreting the attainment date extension Annual PM 10 Standard Attained by December
2001

Clean Air Act Criteria
for Extension of

Attainment Date

Plan Contains Most

Stringent Control

Measures Implemented in any
State6-2 requirement for urban areas such as the Las Vegas Valley. It has, howev er, provided preliminary interpretation of the section 188(e) requirements in the proposed approval of the Maricopa County, Arizona

PM 10 Serious Area Plan (65 FR 19967-19969, April 13, 2000). Our approach to satisfying the MSM requirement is based on the discussion provided by U. S. EPA in this proposed rule and as further described below.

U. S. EPA states that the r equirement for most stringent

measures is similar to t he requirement for the Best
Available Control Measures (BACM). BACM is defined to be, among other things, the maximum degree of

emission reduction achievable from a source or source category which is determined on a case-by-case basis considering energy, economic, and environmental impacts. A similar definition was proposed for a most stringent measure as follows: the maximum degree of emission reduction that has been required or achieved
from a source or source ca tegory in other SIPs or in practice in other states and can feasibly be implemented

in the area.

Given the similarity betw een the BACM implementation and MSM requirements, U. S. EPA noted that the process for determining MSM should follow a process similar to determining BACM, with the added step of comparing the potentially most stringent measure against the measures already adopted in the area to determine if the existing m easures are most stringent. The following five steps were thus proposed by U. S. EPA for determining MSM:

1. Develop a detailed emission inventory of PM 10 sources and source categories;

2. Model to evaluate the impact on PM 10 concentrations over the standards of the various source categories to determine which are significant for the purposes of adopting MSM;

3. Identify the pot entially most stringent measures in other implementation plans or used in practice in other states for each signifi cant source category and, for each measure, determine their technological and economic feasibility for the area; Most Stringent

Measures Must
Achieve the Maximum

Degree of Emissions

Reduction that Has

Been Achieved in
Other States

Five Steps Used to

Determine MSM6-3 4. Compare the potentially most stringent measures for each significant source category against the measures, if any, already adopted for that source category; and

5. Provide for the adoption and expeditious implementation of any MSM that is more stringent than existing measures or, in lieu of adoption, provide a reasoned justific ation for rejecting the potential MSM.

Steps one and two are the same steps prescribed for the BACM analysis as provided in Chapter 4. The emissions inventories and modeling work addressed in that chapter were reeval uated and determined to apply to the MSM analysis. The significant sources that
contribute to exceedances of the 24-hour PM 10 standard, and are thus signifi cant for the purpose of adopting MSM, are the same as for BACM (see Table 4-1) and are included in the following five source categories:

• Disturbed vacant lands;

• Unpaved parking lots;

• Construction activities;

• Paved road dust; and

• Unpaved road dust.

For each of these significant sources, BACM were identified and implemented to ensure expeditious
attainment of the national PM 10 standard. Those sources determined to be insignificant were not
considered further for BACM application.

Because BACM is defined as the best level of control for an area, it is possible that satisfying the MSM requirement would result in no more controls and no
more emissions reductions than result from BACM implementation. U. S. EPA inte rprets the strategy in the nonattainment provisions of the Act as requiring the application of more stringent control measures where feasible to offset longer atta inment time frames such as Clark County is requesting. Two ways were offered as means to identify additional controls that could result in Significant Sources

Are Addressed in

BACM Analysis

Two Approaches for Considering Additional
Controls6-4 a reduced time frame needed to achieve attainment.
One is to reduce the threshold for what is considered a de minimis (insignificant) source, and the second is to reassess any BACM measures rejected during the BACM analysis because they could not be implemented by the BACM implementation deadline.

We evaluated the insignificant source contributions to
determine if new or additiona l controls (as noted in Chapter 4, some controls are already in effect for insignificant sources) c ould be implemented for the insignificant sources that w ould contribute to expediting
the attainment date. T he Valley-Wide 2001 24-Hour Inventory, Table L-21, show s a total mass contribution

after controls of 209 μ g/m 3 against the standard of 150

μ g/m 3 . The total contribution of all insignificant sources, those identified in Table 4-1, is 5.1 μ g/m 3 . Eliminating 100 percent of the insignific ant source contributions would have no effect on achieving earlier attainment of

the 150 μ g/m 3 standard. The same analysis was made for the 2003 inventory (see Chapter 5) which showed

the total controlled concentration to be 184.2 μ g/m 3 , with the insignificant sour ces contributing 13.1 μ g/m 3 . Again, eliminating all insignificant source contributions would not help advance the attainm ent date as the remaining

concentration would still be 171 μ g/m 3 against the 150

μ g/m 3 standard. Since it is necessary to attain three consecutive years of data within the 150 μ g/m 3 standard
in order to demonstrate a ttainment of the national standard, the earliest date fo r attainment would still be December 31, 2006, our r equested extension date, even if all insignificant source emissions were 100 percent controlled. We ther efore conclude that applying MSM to the de minimis source categories cannot meaningfully expedite atta inment, and these sources are not further analyzed for MSM.

The second means listed for identifying possible

additional controls is also not applicable. The initial date for BACM implementation wa s February 8, 1997, and there are no potential BAC M control measures to reconsider now that were rejected because of the BACM implementatio n deadline.

The third step in determining MSM involves identifying the potentially most stringent measures. The extensive Elimination of All Insignificant Source
Contributions Will Not

Advance Attainment
Date

Insignificant Sources
Were Not Further Analyzed for MSM

No Potential BACM
Control Measures Were Rejected Due to

the Implementation
Deadline6-5 research that was done to identify potential BACM to be considered for implementati on in the Las Vegas Valley was also used to identify pot ential MSM. The research
effort is described in the Se ction 4.3, Ident ification of
Potential Control Measures.

Generally, Clark County found the control measures implemented by the five PM 10 serious nonattainment areas are potentially the most stringent measures in use
for control of the same or similar significant sources requiring control in the Las Vegas Valley. Close attention was given to the c ontrols implemented by each of these areas, with particu lar attention paid to the Maricopa Rules 310 and 310. 1, amended February 16, 2000; the South Coast Rule 403, amended December 11, 1998; and the BACM/MSM Analysis contained in U. S. EPA’s Technical Support Document for the Maricopa
Serious Area PM 10 Plan, dated April 6, 2000.

The remaining steps in the process for determining MSM are addressed in the following analysis.

6.3 THE MOST STRINGENT MEASURE ANALYSIS

A most stringent measure analysis was performed for each of the five significant source categories (disturbed vacant lands, unpaved parking lots, construction activities, paved roads, and unpaved roads) similar to the BACM analysis in Chapter 4. A summary table is presented for each source category listing those measures found to be potentially the most stringent measures implemented by others. The measures implemented by Clark County ar e listed for comparison.
A discussion of the com parative analysis of the measures accompanies each table. Each analysis
includes a determination of t he relative stringency of the measures as they apply to the source category. If necessary, additional MSMs are identified for implementation, or a reasoned justification for rejecting potentially more stringent measures is provided.

6.3.1 Disturbed Vacant Lands

For Disturbed Vacant Lands, two categories of control measures were found to be potential MSMs. Close Attention Was
Given to Control
Measures in Other

PM 10 Serious

Nonattainment Areas

A Summary Table Is

Provided for Each MSM Analysis6-6 Stabilization measures and weed abatement are
addressed in the fo llowing paragraphs.

6.3.1.1 Stabilization Requi rements for Disturbed

Vacant Lands The Maricopa Association of Governments (MAG) BACM and MSM analyses that are contained in the
MAG SIP for PM 10 (MAG Plan) cited in this chapter noted two regulations that contained this control
measure. These were t he South Coast Air Quality Management District (SCAQMD) Rule 403 and Clark County Section 41. The U.S. EPA determined that Maricopa Rule 310.01 was more stringent than Clark County Section 41. 1 Following the MAG BACM and MSM analysis, SCAQMD has updated Rule 403 and Maricopa County has updated Rule 310.01. As a result, Clark County compared t he requirements for this source category that are c ontained in the Clark County Air Quality Regulations (AQR) Section 90 to the Maricopa Rule 310.01 and the updated SCAQMD Rule 403. The requirements are summarized in Table 6-1.

1 Technical Support Document ( Notice of Proposed Rulemaking on
the MAG Serious Area PM 10SIP for the Maricopa County NonAttainment Area ), U.S. EPA-Region IX, April 6, 2000. Controls for
Stabilization and Weed

Abatement6-7 Table 6-1

Summary of Stabilization Requirements for

Disturbed Vacant Lands

Agency Rule # Requirements

Clark County,
Nevada AQR § 90.2.2.1(a)

AQR § 90.2.2.1(b)

AQR § 90.2.2.1(c)

AQR § 90.4 • Disturbed areas Σ 5,000 sq. ft., prevent motor vehicle
access and stabilize with wa ter, dust suppressants, or gravel

• Disturbed areas Σ 5,000 sq. ft., stabilize with water,

dust suppressants, or gravel

• Disturbed areas Σ 5,000 sq. ft., apply and maintain

AQD/U. S. EPA approved control measure

• All stabilization subject to drop ball, TFV, b or rock test

• (Proposed) Dust mitigation plans for property owners

with 10,000 acres or greater

Maricopa Co.,

Arizona Rule 310.01 § 301.1

§ 302.1

§ 302.2 • Disturbed areas impacted by motor vehicles Σ 4,356 sq. ft., prevent motor vehicle access; or stabilize with dust suppressants or gravel; or apply and maintain an U. S. EPA approved alte rnative control measure

• Disturbed areas not impacted by motor vehicles Σ

21,780 sq. ft., stabilize dust suppressants or gravel; or apply and maintain an U. S. EPA approved alternative

control measure

• All stabilization subject to drop ball, TFV, b vegetation cover, or rock test

SCAQMD, a

California 403(d)(1) • Disturbed areas must be cont rolled to prevent visible emissions from crossing the property line during winds

of Ρ 25 mph

a South Coast Air Quality Management District (SCAQMD)

b Threshold Friction Velocity test

The requirements of Clar k County AQR Section 90 and Maricopa Rule 310.01 are very similar. For disturbed open areas and vacant lots t hat have been disturbed by vehicular traffic, the thre shold for stabilization is effectively identical. Maricopa County uses a threshold of 4,300 square feet for st abilization, whereas Clark County sets the threshold at 5,000 square feet. Clark County selected the 5,000 square foot threshold because the area dimensions of 50 by 100 can be easily estimated by inspectors and property owners in the field. The 4,300 square foot area equates to “0.1 acre” that is specified in the Ma ricopa rule. A query of the Clark County Assessor’s database, which includes all parcels and improvement val uations in Clark County,
found that the vacant land c ontained in parcels of less than 5,000 square feet m ade up less than one percent Clark County and Maricopa County Requirements Very
Similar

Less than One Percent
of Vacant Land in

Parcels Of 5,000 Square Feet Or Less6-8 of the vacant land contained in the BLM disposal boundary.

Maricopa Rule 310 requires that motor vehicle trespass or access be prevented on any lot greater than 0.1 acre
when over 500 cumulative feet of surface has been disturbed. In lieu of prev enting trespass in such a situation, the owner may apply surface gravel or chemical/organic stabilizers to all disturbed areas. If 0.5
acre or more of disturbed surface area exists, the owner

must stabilize the disturbed su rface area. Water is only an option where motor vehicl e trespass is prevented by barriers. (Where there is no evidence of vehicle trespass, such as when a lot has been weed abated, preventing trespass is not required and the lot may be stabilized by water.) Clark County’s Rule 90 is generally equivalent except for vacant land where motor vehicle trespass/access is occurring. In this situation, Section 90 is more stringent becaus e there is no explicit exemption for lots greater than 5,000 square feet that
have less than 500 cumulative f eet of disturbed surface.

For open areas not disturbed by vehicular traffic, Clark County retains the 5,000 square foot area threshold for stabilization, whereas Maricopa Rule 310.01 sets the threshold for stabilization at 21,780 square feet (0.5 acre). The SCAQMD Rule 40 3 also uses the 0.5 acre
threshold for all for disturbed areas zoned for residential

uses.

The SCAQMD Rule 403(d)(1) utilizes a performance
standard of no visible emissions over a property line in lieu of specific stabilizati on standards and test methods as set forth in the Clark County and Maricopa rules. Clark County believes that the specific stabilization standards contained the Clark County/Maricopa rules provide significantly great er air quality benefits.

The Clark County approach allows for proactive, yearround enforcement of the cont rol measure, whereas the
SCAQMD control measure can only be enforced during a wind event. Because of distance to property line issues, it might be possible to comply with the SCAQMD control measure by only stabi lizing the outer perimeter area of a large disturbed area in some instances. Section 90 Is More Stringent than Maricopa County Rule
310

SCAQMD Uses a Property Line Visible
Emissions Standard

Clark County Provides
for Proactive YearRound Enforcement6-9 The Clark County control measure requires stabilization of disturbed areas subject to the control measure within 30 days of discovery. The Maricopa control measures

mandate stabilization withi n 60 days of “initial discovery.” The SCAQMD control measure does not specifically address this i ssue as the regulation appears to be more geared toward construction activities.

Test methods for stabilization contained in the Clark County and Maricopa regulati ons are identical except that the Clark County regulat ions do not contain test methods for vegetation cover. Vegetation is not allowed as a stabilization method, except with U. S. EPA approval as an alternative stabilization method.

Based on the comparison of requirements discussed above, Clark County finds that the requirements in
Section 90 of the AQR fo r disturbed open areas and vacant lands are of equi valent stringency as the Maricopa Rule 310.01 for disturbed open areas and vacant lots impacted by vehicular traffic, and more stringent than the SCAQMD Rule 403. For disturbed open areas and vacant lots not impacted by motor vehicles, Clark County finds that Section 90 of the AQR is more stringent than both Maricopa Rule 310.01 and
SCAQMD Rule 403.

6.3.1.2 Dust Control for Weed Abatement by Discing or Blading The MAG Plan noted one regulation that contained this
control measure. This was SCAQMD Rule 403. Following completion of t he MAG Plan, SCAQMD has updated Rule 403, but has not changed the requirements for weed abatement. Maricopa County has adopted Rule 310 with specific provisions for weed abatement by discing or blading. Clark County compared these Maricopa requirements for weed abatement with the requirement s contained in the Clark County AQR Section 90 and the updated SCAQMD Rule 403. A summary of these requirements is shown
in Table 6-2. Stabilization Required in 30 Days of

Discovery

Test Methods

Clark County Requirements Equivalent to Maricopa County

Two Programs
Evaluated for Weed Abatement by Discing or Blading6-10 Table 6-2

Summary of Weed Abatement Requirements for Open Areas and Vacant Lands

Agency Rule # Requirements

Clark County,
Nevada AQR § 90.2.2.1(a), (b)

AQR § 90.2.2.1(c)

AQR § 90.4 • Weed abatement of areas Σ 5,000 sq. ft. by discing or blading: apply water prior to and during discing and blading

• After discing or blading occurs, stabilize disturbed

surfaces with gravel, water, dust palliatives, or paving

• All stabilization subject to drop ball, TFV, b or rock test

Maricopa Co.,

Arizona Rule 310 § 308.8

§ 308.8

§ 302.3 • Weed abatement of areas Σ 4,356 sq. ft. by discing or blading: apply water prior to and during discing and blading

• After discing or blading occurs, stabilize disturbed

surfaces with gravel, water, dust palliatives, or paving

• All stabilization subject to drop ball, TFV, b rock test, or vegetative cover test

SCAQMD,
California Rule 403(d)(1) & 403(h)(H) • Disturbed areas must be cont rolled to prevent visible emissions from crossing the property line during winds

of Ρ 25 mph

b Threshold Friction Velocity test

The requirements for weed abatement by discing or blading contained in Clark County AQR Section 90 and Maricopa Rule 310 are virtually identical in terms of the

stabilization methods and test methods utilized. The Maricopa Rule uses a slightly lower action threshold of 4,300 square feet for w eed abatement, whereas Clark County sets the threshold at 5,000 square feet. Clark County selected the 5,000 square foot threshold because the area dimensions of 50 by 100 feet can be easily estimated by inspectors and property owners in the field. The 4,300 square foot area equates to “0.1 acre” that is specified in the Maricopa rule. Clark County believes that in terms of air quality benefits, the two action thresholds for stabilization are equivalent. A query of the Clark County Assessor’s database, which includes all parcels and improv ement valuations in Clark County, found that the vacant land contained in parcels of less than 5,000 square feet made up less than one percent of the vacant land contained in the BLM disposal boundary. Test Methods6-11 Maricopa Rule 310 classes weed abatement by discing or blading as an “earth movi ng” operation and requires a dust control permit to disc or blade any area of 4,300 square feet or larger. Stri ctly speaking, this is an
enforcement mechanism rather than a control measure. Clark County is impl ementing an aggressive enforcement and educational program to ensure compliance with Section 90 of the AQR and does not believe that any additional air quality benefits could be achieved by implementing a permitting program.

In addition to the stabilization methods permitted in the Clark County Regulation, the Maricopa rule also allows for the use of vegetative cove r as a stabilization method. This provision could weaken the Maricopa Rule if proper techniques are not utilized becaus e of the difficulties in establishing vegetation in a dry desert climate and the time needed for vegetative cover to achieve sufficient growth to provide protective cover.

The SCAQMD Rule 403(d)(1) utilizes a performance
standard of no visible emissions over a property line in lieu of specific work practice standards and test methods as set forth in the Clark County and Maricopa rules. As discussed in the stabilization section, Clark County does not believe that the property line performance standard will be effective in some instances or technologically feasible for dust-producing operations that occur next to a property line. The use of this performance standard was rejected as technologically infeasible by Clark County on this basis.
The South Coast Rule also contains a number of exemptions in Subsecti on 403(h)(H) that are not included in the Maricopa and Clark County control

measures.

Based on the comparison of requirements discussed above, Clark County finds that the requirements in
Section 90 of the AQR for weed abatement by discing and blading are of equiva lent stringency as the Maricopa Rule 310 and more stringent than the
SCAQMD Rule 403.

6.3.2 Unpaved Parking Lots

The set of control meas ures for stabilizing unpaved Maricopa County Requires a Dust
Control Plan for Discing or Blading

Use of Vegetative
Cover

SCAQMD Visible

Emissions Limit

Clark County Requirements of Equivalent Stringency6-12 parking lots identified as potential MSM are shown in Table 6-3 along with the control measures adopted by Clark County. An MSM analysis discussion follows.

Table 6-3

Summary of Stabilization Requirements for Unpaved Parking Lots

Agency Rule # Requirements

Clark County,

Nevada AQR § 92.2.1

AQR § 90.2.1.2(a) AQR § 90.2.1.2(b) AQR § 90.2.1.2(c)

AQR § 90.2.1

AQR § 92.4 Stabilize all unpaved parking lots utilized more than 35 days per year with one of the following methods:

• Pave; or

• Stabilize with dust palliatives; or

• Stabilize with dust palliatives in travel lanes and 2” of

uniformly applied gravel in parking areas. For parking lots used intermittently for ≤ 35 days/year, stabilize as above during parking use and stabilize pursuant to AQR Section 90 during non-parking use

• All stabilization subject to 20 % opacity test method and maintenance of silt loading of < 0.33 oz/ft 2 or surface

silt content of ≤ 8 %

• (Proposed) Prohibitions on new unpaved parking lots

• (Proposed) Prohibition on dust crossing over a property

line

Maricopa Co.,
Arizona Rule 310.01 § 301.1

§ 302.1

§ 303.2 Stabilize unpaved parking lots ≥ 5,000 sq. ft. utilized more than 35 days per year with one of the following methods:

• Pave; or

• Stabilize with dust suppressants; or

• Uniformly apply and maintain surface gravel. For parking lots used intermittently for ≤ 35 days/year, stabilize as above during parking use

• All stabilization subject to 20 % opacity test method and maintenance of silt loading of < 0.33 oz/ft 2 or surface

silt content of ≤ 8 %

SCAQMD,
California 403(d)(1) • Disturbed areas must be cont rolled to prevent visible emissions from crossing the property line during winds of < 25 mph

• Apply water

SJVUAPCD

California Regulation 8070 Stabilize unpaved parking lots ≥ 43,560 sq. ft. when used for parking with one of the following methods:

• Stabilize by applying water at least one time per day; or

• Stabilize with dust suppressants at the manufacturers recommended rate for road applications; or

• Uniformly apply gravel to completely cover the area

treated.6-13 6.3.2.1 Stabilization Requirements for Unpaved Parking Lots
The MAG Plan did not ident ify any MSMs for unpaved parking lots that are not a ssociated with construction
sites. 2 Clark County notes that the SCAQMD Rule 403 is not specific to construction activities and would be applicable to unpaved parking lots that are not part of a construction activity. In addition, Regulation 8070 adopted by the San Joaquin Valley Unified Air Pollution Control District (SJV UAPCD) addresses unpaved parking lots that are not utiliz ed as part of a construction activity. In addition, Ma ricopa County has adopted Rule 310.01 to address unpaved parking lots.

The requirements for unpaved parking lots contained in Clark County AQR Section 92 and Maricopa Rule 310.01 are virtually identical in terms of the stabilization methods and test methods used. The Clark County Rule applies to all unpaved parking lots, whereas the Maricopa Rule exempts small unpaved parking lots of 5,000 square feet or less by definition (see 310.01 § 215). Both rules use ident ical performance standards
for visible emissions a nd surface silt on unpaved parking lots.

Stabilization methods allo wed by the Clark County and Maricopa rules vary slightly. The Clark County requirements are somewhat more restrictive on the use of gravel than Maricopa. Specifically, Clark County does not allow use of gravel on travel lanes of unpaved parking lots and requires two inches of gravel to be uniformly applied on parking areas. Although the Maricopa requirements are non-specific on the application of gravel for unpav ed parking lots, the visible
emissions and surface silt r equirements contained in the Maricopa rule will generally ens ure that gravel is applied effectively.

As noted at the beginning of this section, the SCAQMD Rule 403 is nonspecific for unpaved parking lots. However, under Subsection 403(d)(1), operators of unpaved parking lots are required to prevent visible emissions from crossing a property line when wind speeds are 25 miles per hour or less. Clark County has

2 Ibid. Other States’ Control

Measures

Parking Lots Covered by Requirements

Stabilization Methods

SCAQMD Requirements6-14 proposed a prohibition on dust crossing over a property line from unpaved parking lots.

The SJVUAPCD Rule 8070 uses a loose action threshold of one acre (43,560 square feet) for stabilization of unpaved parking lots, and stabilization is only required on days when the parking lot is actually in use. The prescribed stab ilization methods do not have any type of performance standard and, therefore, are of
limited effectiveness. Pre scribed stabilization methods include the application of wa ter at least once per day, the application of chemical dust suppressants, and the application of gravel. Bec ause Rule 8070 contains no performance standard for either visible emissions or surface stabilization, regul atory compliance is achieved with minimal application of one of the prescribed

stabilization methods without co nsideration for its actual effectiveness. Clark County believes that this control measure provides very limited air quality benefits.

Based on the comparison of requirements discussed above, Clark County believes that the requirements in Section 92 of the AQR for unpaved parking lots are marginally more stringent than the requirements of Maricopa Rule 310 and more stringent than the requirements contained in the SCAQMD Rule 403 or
SJVUAPCD Rule 8070.

6.3.3 Construction Activities

Research of the source categories included in construction activities produced a comprehensive set of potential most stringent measures. For analysis purposes, these measures have been grouped into a total of 13 different categor ies. A separate summary table of the potential MS Ms implemented by other jurisdictions and those implem ented by Clark County is provided for each category, as is an MSM analysis of the measures in the group. These analyses begin in
Section 6.3.3.1.

The Maricopa Plan identified the following MSMs for these source categories: SJVUAPCD Requirements

Clark County Requirements Marginally More Stringent6-15 • Dust control plans for construction/land clearing;

• Dust control measures for material storage piles;

• Bulk material rapid stabilization;

• Traffic rerouting or rapid cleanup of dust deposits on paved roads;

• Prohibition of work site unpaved haul roads/parking/staging areas;

• Weed abatement operations

• Require dust control plans for all grading permit activities; and

• Implement high-wind condition BACMs.

Clark County found that prohibiting unpaved haul roads, parking areas, and staging areas was technologically infeasible. In addition, weed abatement is not considered a construction activity under the Clark County regulatory program, but
rather maintenance of di sturbed vacant land. The Clark County control measur e for this activity was discussed earlier in this Chapter. Where brush and vegetation are cleared fo r construction purposes, this activity is addressed under the terms “land clearing” or “grubbing.”

The potential MSM measures discussed in the Maricopa Plan predominat ely originate from
SCAQMD Rule 403. R equirements fr om Imperial County Regulation VIII and Mojave Desert Air Quality Management District (MDAQMD) Rule 403

are also noted. In the Technical Support Document for the Maricopa Serious Area PM 10 Plan (TSD), 3 the
U. S. EPA identified addition al potential MSMs from permit conditions that are being implemented in Clark County under previous AQR Section 17. The work practices cited in the TSD have been expanded and incorporated into the Section 94 Handbook which has been adopted by the Clark County Health District Board of Health for compliance with the requirements of AQR Section 94. Clark County also conducted a survey of construction activity controls which have been implemented in the southwestern
United States. 4 The results of this survey are
summarized in Table 4-3.

3 Technical Support Document, supra

4 Dames & Moore, et. al., supra Potential Most Stringent Measures

for Construction

Prohibiting Unpaved
Haul Roads Infeasible

Potential Sources of Most Stringent

Measures6-16 6.3.3.1 Soil Specific Re quirements for Use of
Surfactants and Tackifiers The Clark County Section 94 Handbook of Best Management Practices for Dust Control (Section 94 Handbook) sets forth soil-spec ific requirements for the use of surfactants and tackifiers. These requirements
are summarized in Table 6-4. This Requirement Is Unique to Clark County

Table 6-4

Summary of Soil Specific Requirements for
Use of Surfactants and Tackifiers

Agency Rule # Requirements

Clark County,

Nevada Section 94 Handbook, Figure 4-1

Section 10-4 • Classifies soil as having a low, moderate low, moderate high, or high emissions potential based on soil silt content and optimum moisture content

• Specific requirements for use of tackifiers & surfactants with moderate high and high soil types

No other agencies are implementing this
control measure

6.3.3.2 Requirement for Dust Control Monitor (Manager) at Large Construction Sites
Table 6-5 summarizes the Cla rk County requirement for a dedicated person as a designated dust control monitor for large construction projects. Construction projects with 50 acres or greater of active, disturbed area are required to have a dust monitor. This Requirement Is Unique to Clark County

Table 6-5

Summary of Requirements for Dust Control Monitor (Manager) at La rge Construction Sites

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.4.11 • Dust control monitor required for Projects with Σ 50 acres of actively disturbed area

• Requirement remains in place until less than 50 acres are actively disturbed and previously disturbed areas have long-term stab ilization in place

No other agencies are implementing this
control measure6-17 6.3.3.3 Site Specific Dust Control Plan and Permit Requirements Requirements for site-specific dust control plans and/or permitting requirements are summarized in Table 6-6.

Table 6-6

Summary of Site-Specific Dust Mitigation Plan and Permit Requirements

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.4.8

AQR § 94.6.8(a) AQR § 94.6.7(d)

AQR § 94.4.9
Section 94 Handbook

AQR § 94.4.9 & AQR § 94.6.8(a) AQR § 94.6.7(d) • Dust Control Permit required with BMP for any soildisturbing activities, based on site-specific project

conditions where construction site ≥ 10 acres, trenching

Θ 100 ft., demolition > 100 ft.

• Failure to implement BMP on permit a violation

• Conducting a dust-producing activity for which no BMP specified in permit

• Site-specific, soil-specific , and phase-specific dust mitigation plan implementing BMP required where

disturbed area/construction site ≥ 10 acres, trenching > 1 mile, demolition with explosives

• Failure to comply with approved plan a violation of dust control permit

• Conducting a dust-producing activity for which no BMP specified in plan a violation

Maricopa Co.,
Arizona Rule 310, § 303 et. sec. § 304.3 • Dust control plan required for operations that entail earthmoving of more Σ 0.1 acre

• Implement one primary and one contingency control for each fugitive dust source from Tables 1& 2

SCAQMD,
California Rule 403(f)(B) • Dust emissions control plan required for operations that

entail ≥ 50 acres of disturbed land or ≥ 5,000 cubic yards of material.

• Plan must identify all sources of fugitive dust

• Plan must implement at least one control measure for all sources of fugitive dust

MDAQMD, a

California Rule 403-1(C)

Rule 403-2(C)(3) • Dust control plan for construction/demolition source, maintain natural topography to extent possible

• Dust control plan for construction source disturbing 100

or more acres

• Describe applicable dust control measures

• Provide stabilized access to the site as soon as possible (prior to project completion)

• Maintain natural topography to extent possible

• Construct parking lots and paved roads first, as feasible

• Construct upwind portions of project first, where
feasible

a Mojave Desert Air Quality Management District (MDAQMD)6-18 The Clark County dust control permit process serves a function similar to the Maricopa requirement for submission of dust control plans. Both processes are designed to implement contro l measures required under provisions of the respective rules. Clark County does not require submission of site-specific dust mitigation plans for projects under ten acres or which meet other
criteria detailed in Table 6-6 in order to expedite processing the permits. A “boilerplate” plan may be used instead. The applic ant must provide the information on all dust-producing activities and proposed control measures (BMP) as is required for the Maricopa Dust Control Plan. Moreover, as noted in Table 6-6, an operator is in vi olation of Section 94 of the AQR if he or she engages in a dust-producing activity that is not covered under the approved permit. The Maricopa action threshold of 0.1 acre is more stringent than the Clark County requirement of 0.25 acre for obtaining a dust control permit. However, the Clark County control measure contains additional requirements that may trigger the permit requirement for a smaller site and BACM is still required.

The Clark County requirement for submission of a dust mitigation plan is a matter of detail and degree over and above the requirement to obtain a dust control permit. The requirement for a dust mi tigation plan is intended to put additional emphasis on soil specificity and phasing for larger projects. Where required, the dust mitigation plan is made an integral part of the dust control permit.

The key element of any dust control permit or dust control/mitigation plan is the stringency, comprehensiveness, and appropr iateness of the control program put forward in the permit or plan. Both the Clark County dust control permit and dust mitigation plan requirements are based on implementation of the
Section 94 Handbook. Clark Co unty believes that this compendium of control measures for all types of construction activities exceed any other set of control measure requirements in te rms of comprehensiveness, effectiveness, and stringency. Although elements of the Maricopa dust control plan pr ocess are more stringent than the Clark County dust control permit/dust mitigation plan program, the overall stringency and benef its of the Clark County program equal s the Maricopa program Clark County and Maricopa County Require Site-Specific

Review of Projects

Clark County Dust Mitigation Plan Places Additional Emphasis on Soil Specificity and Phasing

Clark County Surpasses Other Programs in Terms of Comprehensiveness,

Effectiveness, and Stringency6-19 for smaller projects and ex ceeds the Maricopa program for larger projects.

The SCAQMD emission control plan requirements require submission of a emission control plan for projects of greater than 50 acres. The plan must identify all fugitive dust sources and specify mitigation measures. However, the m enu of mitigation measures provided for in the SCAQMD Rule 403 are less comprehensive than those found in the Clark County Section 94 Handbook, and Rule 403 also lacks the

visible emission limits contai ned in Section 94 of the
AQR. These factors make the Clark County dust control permit/dust mitigation plan program significantly more stringent than the SCAQMD emission control plan requirements.

The MDAQMD Rule 403-1 requires a dust control plan for any construction/demolition project and includes a requirement for maintainin g the natural topography to the extent possible. The MDAQMD Rule 403-2 requires a dust control plan for projects of 100 acres or larger. The plan must identify applic able control measures, and the plan requirements specify special conditions for these large projects. Thes e include providing stabilized access to the site as soon as possible (but prior to project completion); maintenan ce of natural topography to extent possible; constructing parking lots and paved roads first (as feasible); and constructing upwind portions of project first wher e feasible. The Clark County BMPs include stabilizing access roads for the duration of the project and applying paving as soon as possible to all future roadway areas . The air quality benefits and technical feasibility of maintaining the natural topography to the extent possi ble is not known for Clark County, but is thought to be very small.

Overall, the Clark County dust control permit/dust mitigation plan program provides a significantly more stringent program than the combined elements of
MDAQMD Rule 403-1 and 403-2.

6.3.3.4 Visible Emission Limits Requirements for limiti ng visible emissions from construction activities in Clark County SCAQMD Dust Control Plan Requirements

MDAQMD Dust Control Plan Requirements6-20 and other areas are summarized in Table 6-7.

Table 6-7

Summary of Requirements for Limiting Visible Emissions

Agency Rule # Requirements

Clark County,
Nevada AQR § 94.5.2 AQR § 94.6.8(d) AQR § 94.6.8(b) • Limit visible emissions from a ll construction activities to

Ρ

20 % opacity

• Limit visible dust plume from all construction activities

to Ρ 100 yards

• (Proposed) Limit a visible dust plume to less than 100
feet

• (Proposed) Prohibit dust from crossing a property line
Maricopa Co.,

Arizona Rule 310, § 301 • Limit visible emissions from a ll construction activities to

Ρ

20 % opacity

SCAQMD,
California Rule 403(d)(1) &

Table 2 (1a-1) • Prevent visible emissions from all construction activities from crossing property line

• Limit visible dust plume from all earth-moving activities

to ≤ 100 feet

SMAQMD, a

California Rule 403 • Take every reasonable precaution to prevent visible emissions construction activities from crossing property

line

a Sacramento Metropolitan Air Quality Management District (SMAQMD)

Section 94 of the Clark C ounty AQR contain two limits
on visible emissions from construction activities. The primary performance standard is the requirement that
visible emissions not ex ceed an opacity reading of 20 percent based on 12 or 24 time-averaged readings taken at 15-second intervals. A secondary requirement is that visible plumes not extend for more than 100 yards. Although this standard is considered relatively easy to enforce, the relationship between the plume length standard and degree of control is less certain than that of the opacity st andard. Clark County has therefore retained the plume length standard as a secondary means of estab lishing that excessive emissions are occurring. Clark County has also proposed two new requirements where BACM has not been fully implemented. The first is to limit a visible dust plume to less than then 100 feet. The second is to prohibit dust from cr ossing a property boundary.

Maricopa County Rule 310 contains a 20 percent opacity limitation that is i dentical to the Clark County requirement. The SCAQMD contains a plume length Primary Clark County

Visible Emissions

Limit 20 Percent Opacity

Maricopa County

Visible Emissions

Limit 20 Percent Opacity6-21 limitation of 100 feet as an alternative to conducting upwind/downwind monitoring an d a requirement that no visible emissions be permitted to cross a property line. The Sacramento Metropolit an Air Quality Management District (SMAQMD) Rule 40 3 contains a requirement that “reasonable precautions” be taken to prevent dust from crossing a property line. As previously discussed in this chapter, Clark Count y rejected the prevention of dust crossing a property line as technologically
infeasible. The SCAQMD 100-foot limit on dust plume length is clearly more stringent than the 100-yard requirement contained in the Clark County control measure. However, bec ause of the uncertainties related to the level of control achieved by this requirement, Clark County be lieves that the 20 percent opacity requirement implement ed in AQR Section 94 is of equal or greater stringency than the SCAQMD requirement and provides be tter air quality benefits.

6.3.3.5 BACM Required 24 Hours a Day, Seven Days

a Week Requirements for maintain ing dust control at construction sites 24 hours a day, seven days a week, are summarized in Table 6-8. Clark County finds the intent and application of thes e control measures to be equally stringent. SCAQMD Imposes
100-Foot Plume

Length Limit

Clark County’s Requirements Are of Equal or Greater Stringency

Table 6-8

Summary of Requirements for Applying BACM 24 Hours a Day, Seven Days a Week

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.5.2 • Maintain BACM throughout the site for the duration of the project to limit wind erosion and particulate
emissions

• BACM required 24 hours a day, seven days a week

Maricopa Co.,

Arizona Rule 310, § 304.3 • Control measures to be applied to all actual and potential fugitive dust source s, before, after, and while conducting any dust-generating operation, including weekends, after work hours, and on holidays6-22 6.3.3.6 Cessation of Cons truction Activities During High Winds The Clark County requirements for ceasing construction

activities that contribute to a violation and related requirements from other areas are summarized in
Table 6-9. Clark County and Maricopa County Requirements Are Equally Stringent

Table 6-9

Summary of Requirements for High Wind Conditions

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.5.4 • Requires cessation of all activities that cause fugitive dust emissions to exceed 20 % opacity in spite of the
use of BACM

• Requires that watering equipment continue to operate during high-wind conditions

Maricopa Co.,

Arizona Rule 310, § 300.1

Table 2 BACM 1A • Provides that winds over 25 mph shall be an
“affirmative defense” where dust emissions exceed 20 % opacity and all applicable BACM have been implemented

• High wind BACM mandates cessation of dust generating activities after 60-minute average of winds

Θ 25 mph

SCAQMD,
California Rule 410.1(d) • Requires that additional dust mitigation measures be implemented for disturbed areas and storage and handling of bulk materials, and requires cessation of agricultural tilling when winds exceed 25 mph

Clark County is the only agency that has implemented an unconditional requirement to cease dust-generating construction activities when high-wind conditions
overwhelm BACM controls fo r these activities. The Clark County requirement sets the most stringent standard possible for high winds because no lower wind speed limit is set under which construction activities
cannot be halted when wind overwhelms the BACM for dust-generating activities. In addition, the requirement specifically mandates that water trucks and water pulls continue to operate after other dust-producing activities
have been curtailed.

Maricopa County Rule 310 prov ides that winds over 25 mph can be used as an “affirmative defense” in an enforcement action where all applicable BACM has Clark County Requirements6-23 been applied and the 20 percent opacity limit has been violated. However, the rule does not mandate cessation of dust-producing activities in order to utilize this defense. However, BACM No. 1A from the high-wind BACM table requires that dust-generating activities cease when the average wind speed exceeds 25 miles per hour over a 60-minute period. This BACM for high wind effectively sets a curt ailment requirement for high winds. However, this curtailment wind threshold is significantly less stringent than the Clark County

threshold and will also be harder to enforce. In addition, the Clark County control measure requires that water applications continue after dust-producing activities

have been halted. The Mari copa County BACM do not include this requirement. Clark County finds the requirements of AQR Section 94.5.4 to be more stringent than Rule 310, Section 301.1 for curtailing emissions during high-wind c onditions at construction
sites.

The SCAQMD Rule 403.1 requires that additional dust mitigation measures be employed for disturbed areas when wind speeds exceed 25 mph. However, the rule
does not mandate cessation of construction activities during high winds. Therefore, Clark County finds the requirements of AQR Section 94.5.4 to be more stringent than Rule 403.1 for curtailing emissions during high-wind conditions.

6.3.3.7 Control Measures for Stabilizing Disturbed
Soil Requirements for stabilizing disturbed soil are
summarized in Table 6-10.

Clark County has implemented an extensive and integrated set of control meas ures for disturbed areas of

construction sites. These measures are implemented in conjunction with Clark Count y’s dust control permit and dust mitigation plan requirements, and the AQR Section 94 requirement that emissi ons be controlled 24 hours a day, seven days a week. Both short-term an d long-term
stabilization are addressed in the BMP. The two other agencies with the most ex tensive control measure requirements for construction site disturbed areas are Maricopa County and SCAQMD. Based on a comparison of these measur es, it appears that Clark When High Winds
Overwhelm BACM Controls, Construction
Activities Must Cease

Maricopa County

Requirements

Clark County
Stabilization Measures Are the Most Stringent6-24 County requirements are the most stringent for this
control of disturbed soil. Clark County’s Requirements Are the Most Stringent

Table 6-10

Summary of Control Measures for Stabilizing Disturbed Soil

Agency Rule # Requirements

Clark County,

Nevada AQR Section 94.6.8(d)

AQR Section 94.6.8(b)

Section 94 Handbook
CST 10

CST 10-1

CST 10-2

CST 10-3

CST 10-4

CST 10-5
CST 10-6
CST 10-7

CST 11

CST 11-1

CST 11-2

CST 11-3

CST 11-4

CST 11-5

CST 11-6 Visible Emission Limits:

• Limit visible emissions from a ll construction activities to

Ρ

20 % opacity

• Limit visible dust plume from all construction activities from extending more than 100 yards

• (Proposed) Limit visible emission plumes to less then
100 feet

• (Proposed) Prohibit dust from crossing a property line Requirements for All Projects:

• Stabilize disturbed soil throughout construction site

• Stabilize disturbed soil between structures Control Measures for All Soil Types:

• Apply water to stabilize disturbed soil throughout
construction site

• Limit vehicle traffic and disturbance on soils where possible

• If interior block walls are planned, install as early in the construction as possible

• Apply dust palliative based on soil type Control Measures For Specific Soil Types:

• Apply palliative such as gypsum mulch (high soil)

• Install perimeter wind barrier (high soil)

• Apply water to stabilize disturbed soils - soils must be kept in a damp, crusted, or covered condition (moderate high, moderate low and low soils) Requirements for Large Tracts:

• Stabilize soil to comply with dr op ball, TFV, or rock test

• Prevent access to limit soil disturbance
Control Measures for All Soil Types-Large Tracts:

• Prevent access by fencing, ditches, vegetation, berms,
or other suitable barrier or means approved by the
Control Officer

• Install perimeter wind barriers three (3) to five (5) feet high made of material with a porosity of 50 % or less

• Plant perimeter vegetation early. Use of native and drought-tolerant plants with greater than 50 % silhouette area is encouraged

• Stabilize disturbed soil with dust palliative for long-term

stabilization

• Stabilize disturbed soil with vegetation for long-term

stabilization6-25 Table 6-10

Summary of Control Measures fo r Stabilizing Disturbed Soil (continued)

Agency Rule # Requirements

Maricopa Co.,
Arizona Rule 310, Section 301
Section 302.3 • Pave or apply surface rock for long-term stabilization

• Limit visible fugitive dust emissions ≤ 20 % opacity

• For inactive disturbed areas, stabilize soil to comply with drop ball, TFV, vegetative cover, or rock test

SCAQMD,
California Rule 403(d)(1)

Rule 403, Table 2 (3a)

Rule 403, Table 2 (3b)

Rule 403, Table 2 (3c)

Rule 403, Table 2 (3d) • Prevent visible emissions from disturbed surface area from crossing a property line

• Apply water to at least 80 % of all inactive disturbed surface areas on a daily basis when there is evidence of wind-driven fugitive dust, excluding any areas which are inaccessible to watering vehicles due to excessive slope or other safety conditions; or

• Apply dust suppressants in sufficient quantity and frequency to maintain a stabilized surface; or

• Establish a vegetative ground cover within 21 days after active operations have ceased - ground cover must be of sufficient density to expose less than 30 % of unstabilized ground within 90 days of planting, and at all times thereafter; or

• Utilize any combination of c ontrol actions (3a), (3b), and (3c) such that, in total, these actions apply to all
inactive disturbed surface areas

6.3.3.8 Control Measures for Stabilizing
Construction Haul Roads and Traffic Areas Requirements for stabilizing construction haul roads and
traffic areas are summarized in Table 6-11.6-26 Table 6-11

Summary of Control Measures for Stabilizing

Construction Haul Roads and Traffic Areas

Agency Rule # Requirements

Clark County,

Nevada Section 94 Handbook
CST 20

CST 20-1

CST 20-2

CST 20-3
CST 20-4
CST 20-5

CST 20-6

CST 20-7

CST 20-8

CST 20-9

CST 20-10 • Stabilize all off-road traffic and paving areas (all projects)

• Stabilize all haul routes (all projects)

• Limit vehicle speeds to 15 mph (Note: Use of bumps or dips for speed control is encouraged)

• Apply paving as soon as possible to all future roadway

areas

• Apply water to haul routes to stabilize

• Apply dust palliative to haul routes to stabilize

• Apply gravel to off-road traffic and parking areas and

maintain in a stabilized condition

• Apply gravel to haul routes and maintain in a stabilized
condition

• Apply recycled asphalt (or other suitable material) to off-road traffic and parking areas and maintain in a
stabilized condition

• Apply water to off-road traffic and parking areas and

maintain in a stabilized condition

• Apply a dust palliative (designed for vehicle traffic) to off-road traffic and parking areas and maintain in a

stabilized condition

• Supplement dust palliative or aggregate applications with watering, if necessary

Maricopa Co.,

Arizona Rule 310, § 308.4 & Table 1 § 302.2 • Limit vehicle speed to 15 miles per hour or less and limit vehicular trips to no more than 20 per day

• Apply water so that the surface is visibly moist and
subsection 302.2 of this rule is met

• Pave

• Apply and maintain gravel, recycled asphalt, or other suitable material in compliance with subsection 302.2
of this rule

• Apply a suitable dust suppressant in compliance with
subsection 302.2 of this rule6-27 Table 6-11

Summary of Control Measures for Stabilizing

Construction Haul Roads and Traffic Areas (continued)

Agency Rule # Requirements

SCAQMD,
California Rule 403 • Water all roads used for any vehicular traffic at least once per every two hours of active operations [three times per normal eight hour work day]; or

• Water all roads used for any vehicular traffic once daily and restrict vehicle speeds to 15 miles per hour; or

• Apply a chemical stabilizer to all unpaved road surfaces in sufficient quantity and frequency to maintain a
stabilized surface

SJVUAPCD,

California Rule 8020 § 5.3 • Apply sufficient water to on-site roads and off-site access roads to limit opacity to ≥ 40 %

• Apply chemical dust suppressant to on-site roads and off-site access roads to limit opacity to ≥ 40 %

MDAQMD,
California Rule 403-2(C)(3) • Provide stabilized access to the site as soon as possible (prior to project completion)

• Construct parking lots and paved roads first, as feasible

The Clark County, Maricopa County, and SJVUAPCD control measures for unpaved haul roads and traffic areas apply to both on-site and off-site access roads. The MDAQMD control measure also requires the stabilization of access roads as soon as possible, but before completion of the construction site. Both Clark County and Maricopa County require that visible
emissions from traffic areas, haul roads, and access roads not exceed an opacity of 20 percent. The SJVUAPCD requires that visi ble emissions from these sources be limited to an opacity of 40 percent. The SCAQMD sets a fairly aggre ssive set of prescriptive requirements in lieu of upw ind/downwind monitoring. The MDAQMD does not set performance standards in
Rule 403-2.

Both the Maricopa and Clark County rules include a surface silt-loading stabili zation standard. Maricopa Rule 310 allows compliance with either a silt content standard of six percent or a silt loading standard of
0.33 oz/ft 2 . The Section 94 H andbook definition of “stabilized” provides that unpaved haul roads must comply with the AQR 91 stab ilization standards and test Controls Apply to OnSite Haul Roads and
Off-Site Access Roads

Maricopa County Implements a Silt-Loading
Stabilization Standard6-28 methods. These standards in clude a 20 percent opacity standard, and either a maximu m silt content standard of six percent or a silt l oading standard of 0.33 oz/ft 2

. Therefore, the same stab ilization standards apply for unpaved haul roads in both Clark County and Maricopa County.

Beyond the basic requirement that on-site and off-site unpaved haul roads and traffic areas be stabilized as required to comply with visi ble emission limits of the regulation, the Clark C ounty Section 94 Handbook provides ten specific control methods that may be required as appropriate in a dust control permit/dust mitigation plan. The Maricopa County Rule 310 mandates that one primar y and one contingency measure be implemented from five options provided in Rule 310, Table 1.

Based on this overall assessment, Clark County
believes that the AQR Se ction 94 Handbook control
measures for off-site acce ss roads, on-site haul roads, and traffic areas are of equal stringency to the Maricopa County requirements and more stringent than the SCAQMD, SJVUAPCD, and MD AQMD requirements.

6.3.3.9 Control Measures for Track Out Prevention Requirements for preventing tr ack out from construction
activities are summarized in Table 6-12.

In order to limit track out onto paved roads, Clark County has implemented a comprehensive program of mandatory track out control. Traffic must be controlled
to ensure that all traffic utilizes track out control devices to facilitate the cleanup of track out from a limited number of points. St ringent track out cleanup requirements and record-keepi ng requirements are in place to facilitate verifica tion that required track out prevention/cleanup requirem ents have been met. A comprehensive menu of trac k out control options areprovided which can be selected or required on a sitespecific and phase-specific basis. The Section 94

Handbook Includes Ten Specific Control

Methods for Haul

Roads

The Clark County Requirements Are of Equal Stringency to

Other BACM/MSM

Clark County Has

Implemented a Comprehensive Set of
Track Out Prevention and Cleanup Measures6-29 Table 6-12

Summary of Control Measures for Preventing
Track Out from Construction Activities

Agency Rule # Requirements

Clark County,
Nevada Section 94 Handbook,
CST 19

CST 19-1
CST 19-2

CST 19-3

CST 19-4

CST 19-5

CST 19-6

CST 19-7

CST 19-8 Requirements for All Projects

• Install and maintain track out control devices in
effective condition at all access points where paved and unpaved access or travel routes intersect

• All exiting traffic must be ro uted over selected track out control device(s)

• Track out must be cleaned daily, at minimum

• Immediately clean track out from paved surfaces when
it extends 50 feet or more

• Track out conditions, including preventive and corrective measures, must be recorded daily for every day that the construction project access is used by
vehicles

• (Proposed) Prohibition on the use of dry rotary brushes and blower devices to clean up track out Control Measures For All Soil Types

• Pave construction activities roadways as early as possible

• Install gravel pad(s) consisting of 1” to 3” rough diameter, clean, well-graded gravel or crushed rock (location of gravel pads mu st be identified on project map). Minimum dimensions must be 30 feet wide by three inches deep, and, at minimum, 50 feet or the length of the longest haul truck, whichever is greater. Re-screen, wash, or apply additional rock in gravel pad
to maintain effectiveness

• Install wheel shakers in the event that track out cannot be controlled with gravel pads. Clean wheel shakers on a regular basis to maintain effectiveness

• Install wheel washer in the event that track out cannot be controlled with gravel pad and wheel shakers. Maintain wheel washers on a regular basis to maintain
effectiveness

• Install wheel shakers as primary control measures in addition to or in place of gravel pads

• Install wheel washer as primary control measures in addition to or in place of wheel shakers and gravel pads

• Limit site accessibility to r outes with track out control devices in place by installing effective barriers on unprotected routes

• Record track out conditions and cleanup actions in daily project records6-30 Table 6-12

Summary of Control Measures for Preventing
Track Out from Construction Activities (continued)

Agency Rule # Requirements

Maricopa Co.,
Arizona Rule 310, § 308.3(a) &
Table 1 Install A Suitable Track Out Control Device At All Exits Onto a Public Roadway

• Install a grizzly or wheel wash system at all access points

• At all access points, install a gravel pad at least 30 feet wide, 50 feet long, and six inches deep

• Pave starting from the point of intersection with a paved public roadway and extending for a centerline distance
of at least 100 feet and a width of at least 20 feet Cleanup spillage, carry-out, erosion, and/or track out on the following time schedule:

• Immediately, when spillage, carry-out, and/or track out extends a cumulative distance of 50 linear feet or more;

or

• At the end of the work day, when spillage, carry-out, erosion, and/or track out are other than the spillage, carry-out, erosion, and/or tr ack out described above, in subsection 308.3(b)(1) of this rule6-31 Table 6-12

Summary of Control Measures for Preventing
Track Out from Construction Activities (continued)

Agency Rule # Requirements

SCAQMD,
California Rule 403(d)(5)(A) or

Rule 403(d)(5)(B) &
Table 3

Table 3 (1)

Table 3 (2)

Table 3 (3) Prevention and Removal Option A

• Prevent or remove within one hour the track out of bulk material onto public paved roadways as a result of operations Prevention and Removal Option B

• Prevent the track out of bul k material onto public paved roadways as a result of operations and remove such material any time track out extends for a cumulative distance of greater than 50 feet onto any paved public road during active operations; and

• Remove all visible roadway dust tracked out upon public paved roadways as a result of active operations at the conclusion of each work day when active operations cease Track out Control Devices Required For Use With Option B

• Pave or apply chemical stabilization at sufficient concentration and frequency to maintain a stabilized surface starting from the point of intersection with the public paved surface, and extending for a centerline
distance of at least 100 feet and a width of at least 20 feet; or

• Pave from the point of intersection with the public paved road surface, and extending for a centerline
distance of at least 25 feet and a width of at least 20 feet, and install a track out control device immediately adjacent to the paved surface su ch that exiting vehicles do not travel on any unpaved road surface after passing through the track out control device; or

• Any other control measures approved by the Executive
Officer and the U.S. EPA as equivalent to the methods specified in Table 3 may be used

SJVUAPCD,

California Rule 8020 § 5.4

Rule 8020 § 5.4.1

Rule 8020 § 5.4.2

Rule 8020 § 5.4.3 • Limit or remove the accumulation of mud or dirt from public paved roads at the end of the work day, or at a minimum of once every 24 hours when operations are occurring

• The use of dry rotary brushes prohibited without

sufficient wetting to limit visible emissions to ≤ 40 % opacity

• The use of blower devices for removal of deposited

material is prohibited

• The use of track out control devices such as paved

access aprons, gravel strips, and wheel washers is strongly encouraged6-32 Clark County, Maricopa County, and SCAQMD implement identical requi rements for the cleanup of
track out of mud and dirt. T he basic requirement is the immediate cleanup of track out when track out exceeds 50 feet in length; or, at a minimum, daily at the end of the work day when active operations cease. The
SJVUAPCD Rule 8020 includ es the requirement for cleaning up track out once every 24 hours, but lacks the additional requirement t hat track out be cleaned when the accumulated mud and dirt exceeds 50 feet in length.

The SCAQMD Rule 403 provides an alternative option of track out cleanup once every hour. This option eliminates the requirement that track out devices be
maintained at exits. The Maricopa regulation provides an exemption for the use of tr ack out control devices for projects with less than five ac res of disturbed area or for projects where less than 100 cubic yards of bulk
materials are hauled on or of f site per day. The Clark County program does not cont ain this exemption. Where track out devices are used, the SCAQMD offers the option of paving 100 feet or paving at least 25 feet and installing a track out c ontrol device next to the paving. With regard to the track out control device options prescribed under the Clark County and Maricopa County programs, the options provided are similar and appear to be of si milar effectiveness. In certain requirements (for example, the minimum depth of six inches of gravel in gravel pads), the Maricopa County minimum standard appears to be somewhat more stringent. Clark County adopted a smaller minimum depth of three inches in order to minimize problems with vehicle tires di gging into the gravel pad. However, the Clark County r equirement that the gravel be maintained in a clean condition ensures that gravel pads meeting the Clark Count y standard will be at least
as effective as these meet ing the Maricopa standard.
The SJVUAPCD Rule 8020 “s trongly encourages” the use of track out control devices, but does not require their use under the regulation.

The SJVUAPCD Rule contai ns a unique prohibition on the use of dry rotary brushes and blower devices for the cleanup of track out. These prohibitions compensate to some degree for the fact that the SJVUAPCD regulation

does not have a visible em issions standard for all Clark County, Maricopa County, and SCAQMD Implement

Identical Cleanup

Requirements

Other Options and Exemptions

Track Out Control Requirements6-33 construction-related activities. Specific prohibitions on dry rotary brushes, blower devices, and other similar equipment are not necessary in the Clark County and Maricopa County programs because these types of equipment could not be used without violating these agencies’ 20 percent opacity standard for visible emissions. However, in response to public comments made during the SIP devel opment process, Clark County has proposed to formalize this prohibition in
Sections 93 and 94 of the AQR.

In terms of overall compr ehensiveness, integration, and degree of control, Clark Count y finds the AQR Section 94 Handbook track out control program as stringent as, and potentially more stringent than, the Maricopa County program. The Clark County program is somewhat more stringent than the SCAQMD program and significantly more st ringent than the SJVUAPCD program for this control measure.

6.3.3.10 Control Meas ures for Truck Loading Requirements for preventing par ticulate emissions from truck loading are summarized in Table 6-13.

Clark County has implemented a comprehensive soilspecific program for contro lling particulate emissions from loading bulk material in to trucks. This program includes general work practices for handling bulk materials, and specific cont rol measures for controlling emissions from soils that are hydrophobic or which have a high silt content. Hydrophobic soils make dust control using water difficult to achieve. This is in contrast to the SCAQMD that is able to use a 12 percent moisture standard due to the soil types char acteristic to that area. Soils in Clark County have been determined to have an optimum moisture for compac tion varying from less than five percent to 19 percent. Some soils cannot hold enough water to reach a 12 percent moisture content while other soils would not be adequately controlled with a 12 percent moisture content. The types of soils in the Las Vegas Valley make use of a 12 percent moisture requirement less effective a control than the opacity

standard. 5 The controlling standard for Clark County,

5 Dames & Moore Group Company, “ An Evaluation of Incorporating Best Management Practices into the Construction Activities Program.” A report submitted to Cl ark County Particulate Matter Emissions Control Research Advisory Committee. May 5, 2000. 20 Percent Opacity
Limit Precludes Use of

Dry Rotary Brushes
and Blower Devices

Clark County Requirements Potentially More Stringent than Other
BACM/MSM

Clark County Requirements Should

Achieve Greater Air Quality Benefits in

Practice6-34 and that incorporated in t he Maricopa County program, is the 20 percent opacity st andard, which overall is a more effective control due to the variety of soil types present in those regions. Although the Maricopa County and SCAQMD requirements may achieve similar air quality benefits when proper ly implemented, the comprehensive work prac tices implemented by the Clark County program (which include visible emissions limits, requirements for all pr ojects, control measures for all soils, and control measures for specific soil categories) should achieve gr eater air quality benefits in practice and are considered more stringent.

Table 6-13

Summary of Control Measures for Preventing

Particulate Emissions from Truck Loading

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.5.2 AQR § 94.6.8(d) AQR § 94.6.8(b)

Section 94
Handbook -
CST 22

CST 22-1

CST 22-2

CST 22-3

CST 22-4

CST 22-5

CST 22-6

CST 22-7

CST 22-8 Visible Emissions Limits

• Limit visible emissions from a ll construction activities to ≤ 20 % opacity

• Limit visible dust plume from all construction activities to 100 yards

• (Proposed) Limit visible dust plume to 100 feet

• (Proposed) Limit visible emissions from crossing a property line Requirements for All Projects

• Cover all loads on public roadways Control Measures For All Soil Types

• Empty loader bucket slowly

• Keep loader bucket close to the tr uck to minimize the drop height while dumping Control Measures For Specific Soil Types

• Mix material with water and surfactant mixture prior to loading (high soils)

• Spray material with water and surfactant mixture while loading (high soils)

• Mix material with water and tackifier mixture prior to loading (moderate high soils)

• Spray material with water and tackifier mixture while loading (moderate high soils)

• Mix material with water prior to loading (moderate low and low soils)

• Spray material with water while loading (moderate low and low soils)

Maricopa Co.,
Arizona Rule 310, § 301

§ 308.6(a) • During stacking, loading, and unloading operations, apply water as necessary to limit visible emissions to

≤ 20 % opacity

• During stacking, loading, and unloading operations, apply water as necessary to maintain comp liance with the 20 % opacity limit6-35 Table 6-13

Summary of Control Measures for Preventing

Particulate Emissions from Truck Loading (Continued)

SCAQMD,
California Rule 403(d)(1)

Table 2 (1a) • Prevent visible emissions from all construction activities from crossing property line

• Maintain soil moisture content at a minimum of 12 % as determined by ASTM method

6.3.3.11 Control Measures for Importing Soil, Rock,
and Other Bulk Materials Requirements for preventing par ticulate emissions from importing soil, rock, and ot her bulk materials are
summarized in Table 6-14.
Table 6-14

Summary of Control Measures for Pr eventing Particulate Emissions from Importing Soil, Rock, and Other Bulk Materials

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.5.2 AQR § 94.6.8(d) AQR § 94.6.8(b)

Section 94 Handbook

CST 13-1

CST 13-2

CST 13-3

CST 13-4

CST 13-5

CST 13-6 Visible Emissions Limits

• Limit visible emissions from a ll construction activities to

≤ 20 % opacity

• Limit visible dust plume from all construction activities to 100 yards Requirements for All Projects

• Determine PEP of imported material

• Stabilize material while transp orting to prevent fugitive

dust emissions

• Implement Truck Loading BMP (CST 22)

• Stabilize material while unloading to prevent fugitive

dust emissions

• Stabilize material while loadi ng to prevent fugitive dust

emissions

• Install suitable devices to prevent track out (CST 19) Control Measures For All Soil Types

• Use tarps or other suitable enclosures on haul trucks

• Maintain three to six inches of freeboard to minimize spillage

• Check belly-dump truck seals regularly and remove any trapped rocks to prevent spillage

• Clean wheels and undercarriage of haul trucks prior to leaving construction site

• Limit vehicular speeds to 15 mph on the work site

• Keep soils at optimum moisture content while actively handling

• (Proposed) Limit visible dust plume to < 100 feet

• (Proposed) Prohibition on dust plume from crossing a property line6-36 Table 6-14

Summary of Control Measures for Pr eventing Particulate Emissions from Importing Soil, Rock, and Other Bulk Materials (continued)

Agency Rule # Requirements

Maricopa Co.,
Arizona Rule 310, § 301

§ 308.6(a) • During stacking, loading, and unloading operations, apply water as necessary to limit visible emissions to ≤ 20 % opacity

• During stacking, loading, and unloading operations, apply water as necessary to maintain compliance with the 20 % opacity limit Bulk Material Hauling Off Site Onto Paved Public Roadways:

• Load all haul trucks such that the freeboard is not less than three inches; and

• Prevent spillage or loss of bulk material from holes or other openings in the cargo compartment’s floor, sides, and/or tailgate(s); and

• Cover all haul trucks with a tarp or other suitable closure; and

• Before the empty haul truck leaves the site, clean the interior of the cargo compartment or cover the cargo compartment Bulk Material Hauling On Site Within The Boundaries
Of The Work Site (Applicable when crossing a public roadway upon which the public is allowed to travel while construction is underway)

• Load all haul trucks such that the freeboard is not less than three inches; and

• Prevent spillage or loss of bulk material from holes or other openings in the cargo compartment’s floor, sides, and/or tailgate(s); and

• Install a suitable track out control device that controls and prevents track out and/or removes particulate
matter from tires and the exterior surfaces of haul
trucks and/or motor vehicles that traverse such work
site

Both Clark County and Maricopa County have implemented a comprehensive program for controlling particulate emissions from hauling bulk material, such as soil and rocks, that is well integrated with other
control measures such as track out control and truck loading. No other progra ms evaluated by Clark County came close to being as comprehensive and providing the air quality benefits of thes e two programs. The Clark County program provides some soil-specific work Clark County Requirements Are of Equal Stringency as

Other BACM/MSM6-37 practices that are not incl uded in the Maricopa County program. In addition to m eeting a 20 percent opacity standard for hauling activities, haul trucks must either be covered while carrying loads on site, maintain three to six inches of freeboard, or keep soils at their optimum
moisture content. Trucks must be cleaned and checked for leaks before leaving the si te over a track out control device. The Maricopa County program also makes most of these work practices mandatory, except that freeboard is required to be not less than three inches, and the use of tarps or keeping materials at optimum moisture content are not options. Clark County believes both programs will provide equ ivalent air quality benefits and are of equival ent stringency.

6.3.3.12 Control Measures for Stockpiles Requirements for preventing par ticulate emissions from storage piles are summarized in Table 6-15.

As shown by the Table 6- 15 summary, both the Clark County and Maricopa County programs implement very stringent requirements for stockpiles. The Clark County program is very comprehensive and includes special
control measures for difficu lt soils. The standard for stabilizing inactive stockpiles is defined in the Section 94 Handbook, which by definition requires compliance
with the AQR Section 90.2 stabilization standards. The Maricopa County program incl udes rigorous stabilization
standards that are somewhat less flexible than the options provided for in t he Clark County program but
which will be effective at c ontrolling emissions. Clark County believes both programs are equally stringent in terms of air quality benefits achieved.

The Imperial County Air Po llution Control District (IMAPCD) Rule 403 incl udes a control option of spraying the storage pile with water 15 minutes prior to handling that is not incl uded in the Clark County and Maricopa County programs. Ho wever, the Clark County BMP of handling soil at optim um moisture content is equal to or more stringent than the Imperial County presoaking requirement. The SCAQMD Rule 403 requirements are generally less stringent than the Clark County and Maricopa County programs. Clark County Program Emphasizes Comprehensiveness and Flexibility

Clark County Requirements Are of Equal Stringency as

Other BACM/MSM6-38 Table 6-15

Summary of Control Measures for Preventing Particulate Emissions from Stockpiles

Agency Rule # Requirements

Clark County,
Nevada AQR § 94.5.2 AQR § 94.6.8(d) AQR § 94.6.8(b)

Section 94 Handbook
CST 18

CST 18-1
CST 18-2
CST 18-3

CST 18-4

CST 18-5

CST 18-6

CST 18-7

CST 18-8

CST 18-9

CST 18-10 Visible Emissions Limits

• Limit visible emissions from a ll construction activities to

≤ 20 % opacity

• Limit visible dust plume from all construction activities to 100 yards

• (Proposed) Limit visual dust plume 100 feet

• (Proposed) Prohibition on dust crossing a property line Requirements for All Projects

• Stabilize stockpiles

• Stockpiles located within 100 yards of occupied buildings must not be constructed over eight (8) feet in height

• Stockpiles over eight (8) feet high and not covered must have a road bladed to the top to allow water truck/pull access or must have a sprinkler irrigation system installed that is c apable of complete stockpile

coverage Control Measures For All Soil Types

• Stockpile at optimum moisture content

• Remove material from the downwind side of the stockpile

• To the extent possible, maintain stockpile to avoid steep sides or faces

• Stabilize material in stockpile and surrounding area following stockpile-related activity Control Measures For Specific Soil Types

• Apply water and surfactant during stacking, loading and unloading operations (high soils)

• Apply palliative to all outer surfaces of the stockpile (high soils)

• Provide and maintain wind barriers on three (3) sides of the pile, whose length is no less than equal to the length of the pile, whose distance from the pile is no more than twice the height of the pile, whose height is equal to the pile height, and made of material with a porosity of 50 % or less (high soils)

• Apply temporary cover or screen in lieu of wind barrier (high soils)

• Apply water and tackifier during stacking, loading, and unloading operations (moderate high soils)

• Apply palliative to all outer surfaces of the stockpile (moderate high soils)6-39 Table 6-15

Summary of Control Measures for Preventing Particulate Emissions from Stockpiles (continued)

Agency Rule # Requirements

Clark County,
Nevada (continued) CST 18-11

CST 18-12

CST 18-13 • Provide and maintain wind barriers on three sides of the pile, whose length is no less than equal to the length of the pile, whose distance from the pile is no more than twice the height of the pile, whose height is equal to the pile height, and made of material with a porosity of 50 % or less (moderate high soils)

• Apply palliative and provide wind barriers on three sides of the pile as high as the pile and made of material with a porosity of 50 % or less (moderate high soils)

• Apply water during stacking, loading, and unloading operations (moderate low & low soils)

Maricopa Co.,

Arizona Rule 310, § 301 & § 308.6(a)

§ 308.6(b) • During stacking, loading, and unloading operations, apply water as necessary to limit visible emissions to ≤ 20 % opacity When not conducting stacking, loading, and unloading operations, comply with one of the following work practices:

• Cover open storage piles with tarps, plastic, or other material to prevent wind from removing the coverings;

or

• Apply water to maintain a soil moisture content at a minimum of 12 %, as determined by ASTM method or maintain at least 70 % of optimum moisture content where the optimum moisture is less than 12 %; or

• Stabilize storage pile surface by 1) maintaining visible crust; or 2) maintaining compliance with TFV standards; or 3) maintain vegetative cover per test methods; or 4) maintaining ≥ 10 cover of sheltering elements; or 5) compliance with approved alternative

test method

• Construct and maintain wind barriers, storage silos, or a three-sided enclosure with walls, whose length is no less than equal to the length of the pile, whose distance from the pile is no more than twice the height of the pile, whose height is equal to the pile height, and whose porosity is no more than 50 %. Where this option is utilized, the moisture or stabilization requirements set forth above are still applicable6-40 Table 6-15

Summary of Control Measures for Preventing Particulate Emissions from Stockpiles (continued)

Agency Rule # Requirements

IMAPCD, a

California 403(I)(4)(a)

403(I)(4)(b)

403(I)(4)(c) • Spray with water 15 minutes prior to handling and/or at points of transfer

• Chemical/physical stabilization

• Protect from wind erosion by sheltering or enclosing

the operation and transfer line

SCAQMD,
California Rule 403(d)(1)

Table 2 (5a) Table 2 (5b)

Table 2 (5c)

Table 2 (5d) • Prevent visible emissions from all construction activities from crossing property line

• Apply chemical stabilizers; or

• Apply water to at least 80 [70] percent of the surface area of all open storage piles on a daily basis when there is evidence of wind-driven fugitive dust; or

• Install temporary coverings; or

• Install a three-sided enclosure with walls with no more than 50 percent porosity which extend, at a minimum, to the top of the pile

a Imperial County Air Pollution Control District (IMAPCD)

6.3.3.13 Control Measures for Cut and Fill Operations Requirements for cut and fill operations, including grading and earthmoving, are summarized in
Table 6-16.

Clark County Section 94 of t he AQR provides that all cut and fill operations maintain visible emissions limits for construction activities and employ applicable BMP from the Section 94 Handbook. Applicable BMP for cut and fill operations are found in Se ction 7 of the Section 94 Handbook. Section 7 includes practices applicable to all projects, practices specific to soil categories, and practices applicable to all soils. Practices applicable to all projects include presoaki ng and stabilization of soils prior to cut and fill activiti es; stabilization during cut and fill activities; and stabilizing after cut and fill activities Soils in the high category are to be presoaked to the depth of the cut with a water and surfactant mixture. Soils in the medium high category are to be presoaked to the depth of the cut with a wa ter and tackifier mixture. Clark County Requires Specific Best Management Practices
Based on Soil

Categories6-41 Soils in the other two categories may be soaked to the depth of the cut with water. Six additional control options which may be employed selectively are provided
for all soils.

Table 6-16

Summary of Control Measures fo r Cut and Fill Operations

Agency Rule # Requirements

Clark County,

Nevada AQR § 94.6.8(d)

AQR § 94.6.8(b)
Section 94 Handbook
CST 07

CST 07-1

CST 07-2

CST 07-3

CST 07-4

CST 07-5

CST 07-6

CST 07-7

CST 07-8

CST 07-9 Visible Emission Limits

• Limit visible emissions from a ll construction activities to

≤ 20 % opacity

• Limit visible dust plume from all construction activities from extending more than ≥ 100 yards

• (Proposed) Limit visible plume from extending ≥ 100
feet

• (Proposed) Prohibition on visible plume crossing a property line Requirements for All Projects:

• Presoak soils

• Stabilize soils prior to cut and fill activities

• Stabilize soil during cut and fill activities

• Stabilize soil after cut and fill activities Control Measures Applicable to All Soils:

• Pre-water with sprinklers or wobblers to allow time for penetration

• Pre-water with water trucks or water pulls to allow time for penetration

• Dig a test hole to depth of cut or equipment penetration to determine if soils are moist at depth. Continue to pre-water if not moist to depth of cut

• Use water truck/pull to water soils to depth of cut prior to subsequent cuts

• Apply water to form crust on soil following fill and compaction

• Apply dust palliative to form crust on soil following fill and compaction Control Measures for Specific Soil Types:

• Pre-water with water and surfactant mixture until soil is moist to a depth of cut or equipment penetration (high soils)

• Pre-water with water and tackifier mixture until soil is moist to a depth of cut or equipment penetration (medium high soils)

• Water until soil is moist to a depth of cut or equipment penetration (moderate low, low)6-42 Table 6-16

Summary of Control Measures fo r Cut and Fill Operations (continued)

Agency Rule # Requirements

Maricopa Co.,

Arizona Rule 310, § 301 & Table 1 Disturbed Surface Areas - Pre-Activity:

• 1D Pre-water site to the depth of cuts

• 2D Phase work to reduce the amount of disturbed surface areas at any one time During Dust Generating Operations:

• 3D Apply water or other suitable dust suppressant, in compliance with 20 % Opacity Limit of Rule 310

• 4D Apply water as necessary to maintain a soil moisture content at a minimum of 12 %, as determined by ASTM Method D2216-98 or other equivalent as approved by the Control Offi cer and the Administrator of U. S. EPA. For areas which have an optimum moisture content for compaction of less than 12 %, as determined by ASTM Method D1557-91(1998) or other equivalent approved by the Control Officer and the Administrator of U. S. EPA, maintain at least 70 % of the optimum soil moisture content

• 5D Construct fences or 3 foot - 5 foot high-wind barriers with 50 % or less porosity adjacent to roadways or
urban areas that reduce the amount of windblown material leaving a site. If constructing fences or wind barriers, must also implement 3D or 4D above6-43 Table 6-16

Summary of Control Measures fo r Cut and Fill Operations (continued)

Agency Rule # Requirements

SCAQMD,
California Rule 403 Table 2 Earth-moving (except cut and fill; and mining)

• Maintain soil moisture content at a minimum of 12 percent, as determined by ASTM method D-2216, or other equivalent method a pproved by the Executive Officer, the California Air Resources Board, and the
U.S. EPA. Two soil moisture evaluations must be conducted during the first three hours of active operations during a calendar day, and two such evaluations during each subsequent four-hour period of active operations; or

• For any earth-moving which is more than 100 feet from all property lines, conduct watering as necessary to prevent visible dust emissions from exceeding 100 feet in length in any direction Earth-moving - Construction fill areas

• Maintain soil moisture content at a minimum of 12 percent, as determined by ASTM method D-2216, or other equivalent method a pproved by the Executive Officer, the California Air Resources Board, and the U.S. EPA. For areas which have an optimum moisture content for compaction of less than 12 percent, as determined by ASTM Method 1557 or other equivalent method approved by the Ex ecutive Officer and the
California Air Resources Board and the U.S. EPA, complete the compaction process as expeditiously as possible after achieving at least 70 percent of the optimum soil moisture content. Two soil moisture evaluations must be conducted during the first three hours of active operations during a calendar day, and

two such evaluations durin g each subsequent four-hour period of active operations Earth-moving - Construction cut areas and mining operations

• Conduct watering as necessary to prevent visible emissions from extending more than 100 feet beyond the active cut or mining area unless the area is inaccessible to watering vehicles due to slope conditions or other safety factors

The Maricopa County Rule 310 includes a visible emissions limit based on opacity, disturbed surface area pre-activity requireme nts, and dust-generating operations requirements. Al though less specific to cut and fill operations than the Cla rk County requirements, the Maricopa County requirements generally achieve Maricopa County Requirements6-44 the same efforts in terms of presoaking and moisture penetration, control during operations, and control after operations with one signific ant difference. The Maricopa County regulation relies on moisture content,
whereas the Clark Count y regulation emphasizes custom application of su rfactants and tackifiers on difficult soils by specific soil category. The Section 94 Handbook provides specific guidance on which product (surfactant or tackifier) is needed to achieve control. Although the moisture st andards contained in the Maricopa County regulation ma ke the establishment of a violation fairly straightfo rward, Clark County believes that the customized approach to achieving moisture penetration and particulate cont rol will result in greater
overall emission reductions and air quality benefits.

The SCAQMD Rule 403 provides requirements for general earthmoving, construction fill areas, and construction cut areas. For earthmoving operations, a moisture content and plume leng th limit of 100 feet are mandated. For construction fill areas, a moisture content requirement and the requirement that compaction be completed as expeditiously as possible is applicable. For construction cut areas, watering must occur as necessary to prevent a visible plume from extending more than 100 feet.

Based on this assessment, Clark County finds that AQR Section 94 Handbook, Section 7 practices are of equal or greater stringency than the Maricopa County Rule 310 and of greater stringency than SCAQMD Rule 403 for construction cut and fill operations.

6.3.4 Paved Roads

Control measures to r educe emissions from paved roads are broken into two categories. The first category
of controls reduces silt l oading by limiting the deposition of materials on the roadway. Measures to limit deposition include stabilizing unpaved shoulders and preventing track out. These measures are analyzed in the next two sections. The second group of control measures involve the cleanup or removal of material already deposited on the roads . The list of potential MSMs and the MSM analysis fo r these measures are in Sections 6.3.4.3 through 6.3.4.5. SCAQMD Requirements

Clark County Requirements Equal or
Exceed other

BACM/MSM

There Are Two Categories of Control

Measures for Paved

Roads6-45 6.3.4.1 Control Measur es for Stabilization of Unpaved Shoulders on Paved Roads Requirements for stabilization of unpaved shoulders on paved roads are summarized in Table 6-17.

Table 6- 17

Summary of Stabilization Requirements for Unpaved Shoulders on Paved Roads

Agency Rule # Requirements

Clark County,

Nevada AQR Section 93.2.1.1
& Section 93.2.1.5

AQR Section 93.2.2 New & Modified Paved Roads

• Pave 4 ft. shoulders; or

• Stabilize 4 ft. shoulders with dust palliative and

maintain silt loading of < 0.33 oz/ft 2 and prevent visible emissions from exceeding 20 % opacity; or

• Stabilize 4 ft. shoulders with 2 inches of gravel

• (Proposed) Stabilize shoulders 8 feet or provide

curbing on roads with ≥ 3,000 ADT Existing Paved Roads

• Pave or stabilize shoulders within 365 days of discovery of non-compliance

• SIP commitment to have all shoulders paved or stabilized by 12/31/06

SJVAQMD Rule 8060
Section 5.1.1 New & Modified Paved Roads

• Paved roads with Annual Average ADT ≥ 500, pave or
stabilize 4 ft. shoulders

• Paved roads with Annual Average ADT ≥ 3000, pave
or stabilize 8 ft. shoulders Existing Paved Roads

• No requirements

SCAQMD, a

California Rule 1186(e)(1)(A) New Construction or Widening of Paved Roads

• Paved roads with Annual Average ADT ≥ 500, pave or
stabilize 4 ft. shoulders

• Paved roads with Annual Average ADT ≥ 3000, pave or
stabilize 8 ft. shoulders Existing Paved Roads

• No requirements Maricopa Co.,

Arizona None New & Modified Paved Roads

• No regulatory requirements

• SIP commitment to upgrade roads based on local improvement programs

a South Coast Air Quality Management District (SCAQMD)

Clark County has implemented the only program to eliminate unstabilized shoulders on all paved roads to
reduce track on of mud and di rt. Both the SJVUAPCD and SCAQMD have implemented requirements for paving or stabilizing new and modified roads, but no other program has included provisions for bringing Clark County Road
Shoulder Requirements6-46 existing paved roads up to minimum standards for
shoulders. The SJVUAPCD and SCAQMD regulations also require eight feet of pav ing or stabilization for roads with ADT of greater than or equal to 3,000 based on AASHTO standards. Clark County does not believe that this issue constitutes a significant weakness in the Clark County program, but is proposing to adopt this for new roads as well. Because the Clark County program addresses existing paved roads, interim stabilization of paved road shoulders wil l be needed pending road improvements that will occu r under capital improvement programs. Based on this assessment, Clark County
believes that the Clark C ounty program has a greater overall stringency than ot her programs which have implemented this control measure.

6.3.4.2 Control Measur es for Prevention of Track
Out Onto Paved Roads Requirements for preventing track out onto paved roads
are summarized in Table 6-18. Stringency of Clark County Requirements
Exceed Other

BACM/MSM

Table 6- 18

Summary of Requirements for Prevention of
Track Out Onto Paved Roads

Agency Rule # Requirements

Clark County,

Nevada AQR Section 94.6.8(d)

AQR Section 94.6.8(b)

Section 94 Handbook
Section 19 Visible Emission Limits

• Limit visible emissions from a ll construction activities to

≤ 20 % opacity

• Limit visible dust plume from all construction activities

from extending more than 100 yards

• (Proposed) Limit visible dust plum from construction

activities from extending more than 100 feet

• (Proposed) Prohibition of visible dust plume from crossing

a property line Requirements for All Projects

• Install and maintain track out control devices in effective

condition at all access points where paved and unpaved
access or travel routes intersect

• All exiting traffic must be ro uted over selected track out

control device(s)

• Track out must be cleaned daily, at minimum

• Immediately clean track out from paved surfaces when it

extends 50 feet or more

• (Proposed) Prohibition on use of dry rotary brushes or

blower devices for the clean up of track out6-47 Table 6- 18

Summary of Requirements for Prevention of
Track Out Onto Paved Roads (continued)

Clark County,
Nevada (continued) Section 94 Handbook
CST 19-1
CST 19-2

CST 19-3

CST 19-4

CST 19-5

CST 19-6

CST 19-7

CST 19-8

CST 13-1
CST 13-2

CST 13-3

CST 13-4

CST 13-5
CST 13-6 • Track out conditions, including preventive and corrective measures, must be recorded da ily for every day that the construction project access is used by vehicles Control Measures For All Soil Types

• Pave construction activities roadways as early as

possible

• Install gravel pad(s) consisting of 1” to 3” rough diameter,

clean, well-graded gravel or crushed rock (location of gravel pads must be identified on project map). Minimum dimensions must be 30 feet wide by three inches deep, and, at minimum, 50’ or the length of the longest haul truck, whichever is greater. Re-screen, wash, or apply additional rock in gravel pad to maintain effectiveness

• Install wheel shakers in the ev ent that track out cannot be

controlled with gravel pads. Clean wheel shakers on a regular basis to maintain effectiveness

• Install wheel washers in the event that track out cannot

be controlled with gravel pad and wheel shakers. Maintain wheel washers on a regular basis to maintain
effectiveness

• Install wheel shakers as primary control measures in

addition to or in place of gravel pads

• Install wheel washers as primary control measures in

addition to or in place of wheel shakers and gravel pads

• Limit site accessibility to r outes with track out control

devices in place by installing effective barriers on unprotected routes

• Record track out conditions and cleanup actions in daily

project records

• Use tarps or other suitable enclosures on haul trucks

• Maintain three (3) to six (6) inches of freeboard to

minimize spillage

• Check belly-dump truck seals regularly and remove any

trapped rocks to prevent spillage

• Clean wheels and undercarriage of haul trucks prior to

leaving construction site

• Limit vehicular speeds to 15 mph on the work site

• Keep soils at optimum moisture content while actively

handling6-48 Table 6- 18

Summary of Requirements for Prevention of
Track Out Onto Paved Roads (continued)

Agency Rule # Requirements

Maricopa Co.,
Arizona Rule 310 § 301 & Rule 310.01 § 306 Rule 310 § 308.3(a) &
Table 1

Rule 310 § 308.3

Rule 310 § 308.1 Visible Emissions Limit

• Control dust to comply with 20 % opacity limit
Install A Suitable Track Out Control Device At All Exits Onto a Public Roadway

• Install a suitable track out device such as a grizzly or

wheel wash system at all access points

• Install a gravel pad at least 30 feet wide, 50 feet long, and

six inches deep

• Pave starting from the point of intersection with a paved

public roadway and extending for a centerline distance of
at least 100 feet and a width of at least 20 feet Cleanup spillage, carry-out, erosion, and/or track out on the following time schedule:

• Immediately, when spillage, carry-out, and/or track out

extends a cumulative distance of 50 linear feet or more;

or

• At the end of the work day, when spillage, carry-out,

erosion, and/or track out are other than the spillage, carry-out, erosion, and/or tr ack out described above, in subsection 308.3(b)(1) of this rule Bulk Material Hauling Off site Onto Paved Public Roadways:

• Load all haul trucks such that the freeboard is not less

than three inches; and

• Prevent spillage or loss of bulk material from holes or

other openings in the cargo compartment’s floor, sides, and/or tailgate(s); and

• Cover all haul trucks with a tarp or other suitable closure;

and

• Before the empty haul truck leaves the site, clean the

interior of the cargo compartment or cover the cargo compartment6-49 Table 6- 18 Summary of Requirements for Prevention of
Track Out Onto Paved Roads (continued)

Agency Rule # Requirements

Maricopa Co.,
Arizona (continued) Rule 310 § 308.2 Bulk Material Hauling On Site Within The Boundaries
Of The Work Site (Applicable when crossing a public roadway upon which the public is allowed to travel while construction is underway)

• Load all haul trucks such that the freeboard is not less

than three inches; and

• Prevent spillage or loss of bulk material from holes or

other openings in the cargo compartment’s floor, sides, and/or tailgate(s); and

• Install a suitable track out c ontrol device that controls and

prevents track out and/or removes particulate matter from
tires and the exterior surfaces of haul trucks and/or motor

vehicles that traverse such work site

• Cleanup of deposited material within 24 hours of

discovery

SCAQMD,
California Rule 403(d)(5)(A) or

Rule 403(d)(5)(B) &
Table 3

Table 3 (1)

Table 3 (2)

Table 3 (3) Prevention and Removal Option A

• Prevent or remove within one hour the track out of bulk

material onto public paved roadways as a result of operations Prevention and Removal Option B

• Prevent the track out of bul k material onto public paved

roadways as a result of operations and remove such material any time track out extends for a cumulative distance of greater than 50 feet onto any paved public road during active operations; and

• Remove all visible roadway dust tracked out upon public

paved roadways as a result of active operations at the conclusion of each work day when active operations

cease Track out Control Devices Required For Use With Option B

• Pave or apply chemical stabilization at sufficient

concentration and frequency to maintain a stabilized surface starting from the point of intersection with the public paved surface, and extending for a centerline
distance of at least 100 feet and a width of at least 20 feet; or

• Pave from the point of intersection with the public paved

road surface, and extending for a centerline distance of at least 25 feet and a width of at least 20 feet, and install a track out control device immediately adjacent to the paved surface such that exiti ng vehicles do not travel on any unpaved road surface after passing through the track out control device; or Any other control measures approved by the Executive
Officer and the U.S. EPA as equivalent to the methods specified in Table 3 may be used6-50 Both Clark County and Maricopa County have an extensive set of requirement s in place to prevent mud and dirt track out onto paved roads. The Clark County

measures include visible emissions limits and measures specific for each construction activity taking into account

soil characteristics. These measures are integrated in
the new AQR Section 94 Handbook. The comprehensiveness of both programs for controlling track out, while not identical, result in similar overall control effectiveness. As addressed previously in Section 6.3.3.9, t he overall analysis of the programs to control track out concluded that the Clark County program is as stringent as the Maricopa program and more stringent than that implemented by the SCAQMD.

6.3.4.3 Control Measur es for Acquisition of

PM 10 -Efficient Sweepers Requirements for acquiring PM 10 -Efficient Street Sweepers for use on paved roads and paved parking
lots are summarized in Table 6-19.

Table 6- 19

Summary of Requirements for Acquisition of PM 10 -Efficient Sweepers for Use on Paved Roads and Paved Parking Lots

Agency Rule # Requirements Clark County,

Nevada AQR Section 93.2.3 &
Section 93.2.3.1 • Requires purchase or lease of PM 10 -efficient street sweepers for sweeping street s or paved parking lots
SCAQMD, a

California Rule 1186(d)(2) • Requires government agencies to purchase or lease

PM 10 -efficient street sweepers for sweeping streets

Maricopa Co.,

Arizona SIP Commitment • Commitment by cities, towns, and the County to purchase

PM 10 -efficient street sweepers

• Allocation of $3.8 million in CMAQ funds to support

program

a South Coast Air Quality Management District (SCAQMD)

In reviewing the sweeping equipment utilized by public agencies in Clark County, it was determined that most of the equipment operated by public agencies already complied with the certification requirements for PM 10 - efficient street sweeping equipment. The Clark County regulatory program goes one step beyond other programs for this control measure by making the requirement applicable to private operators and equipment used on parking lots. Most Public Agency Sweeper Fleets Comply with Standard6-51 Clark County, therefore, belie ves that this is the most stringent program for th is control measure.

6.3.4.4 Control Measur es for Street Sweeping Frequency Programs for frequent street sweeping are summarized
in Table 6-20.

Table 6-20

Summary of Street Sweeping Frequency for

Paved Roads

Area Agency Sweeping Program Clark County Public Works • All classes of roads are swept every 7 to 10 days City of Henderson • High silt roads are swept once a week. Other roads are swept twice monthly City of Las Vegas • All classes of roads are swept every 2 weeks. Problem areas, such as roads around active construction sites, are swept more frequently, typically once per week City of North Las Vegas • All roads are swept twice monthly Clark County,

Nevada

State of Nevada • All freeways in Clark County are swept once a
week

• All arterials under state jurisdiction in Clark County are swept once a month Maricopa Association of
Governments • Commitment to allocate $3.8 million CMAQ funds for PM-efficient sweepers

• Funding dispersed competitively based on commitment to utilize equipment. Program designed to encourage additional sweeping efforts by local agencies City of Avondale • Conducts routine sweeping of residential streets

Town of Carefree • Program for sweeping streets as necessary

Town of Cave Creek • Sweeps streets twice a year utilizing rented

sweepers

• Also utilizes two water tr ucks to flush paved roads

as needed City of Chandler • Has increased street sweeping on residential streets to once every 30 days and arterial streets to once every 14 days

• Downtown streets are swept once a week City of El Mirage • Sweeps streets four times a year using

contractors
Town of Fountain Hills • Sweeps streets on a frequent basis

Town of Gilbert • Downtown area streets are swept once a week

• Residential streets are swept once a month Maricopa Co.,
Arizona

City of Glendale • Regularly sweeps streets using mechanical broom

sweepers6-52 Table 6-20

Summary of Street Sweeping Frequency for

Paved Roads

(continued)

Area Agency Sweeping Program City of Goodyear • Sweeps streets on a daily basis using a mechanical broom sweeper City of Mesa • Conducts periodic sweeping of residential and major arterial streets City of Paradise Valley • Initiating an enhanced street sweeping program. Program goal is to sweep every street once every six weeks. Currently, streets are swept once every 3 months City of Peoria • All streets are currently swept once a month. The City is working to increase the sweeping frequency to once every two weeks City of Phoenix • Conducts periodic sweeping of residential and major arterial streets. The City will continue to consider new PM-efficient street sweeping equipment
Town of Queen Creek • Sweeps all curb and gutter streets four times per

year City of Scottsdale • Sweeps all curbed miles of residential streets approximately once every three weeks

• Commuter streets are swept once per week

• Downtown streets are swept twice per week

• City will continue to consider new PM-efficient street sweeping equipment City of Surprise • Sweeps streets once every ten working days

• Heavily traveled arterials are swept more frequently as needed City of Tempe • Routinely sweeps all streets. Streets in the downtown are flushed after special events City of Tolleson • Pursuant to Zoning Ordinance, Article IV, the City commits to strengthen its commitment to increase the frequency of street sweeping Town of Wickenburg • Routinely sweeps all paved streets Town of Youngtown • Ongoing monthly program of sweeping public

streets Maricopa Co.,
Arizona (continued)

Arizona Department of Transportation • Provides for street sweeping on state highways through intergovernmental agreements and
contractors. These effo rts are supplemented by ad hoc sweeping performed by state personnel using state-owned equipment6-53 Based on the information contained in the Maricopa County SIP, the sweeping programs implemented in Clark County provide for mo re frequent street sweeping overall than programs implement ed in Maricopa County. When the ratio of PM-efficient street sweeping equipment is factored into this analysis, the Clark County programs provide for much greater emissions reductions than equivalent programs in Maricopa County.

6.3.4.5 Control Measures for Cleanup of Deposition from Natural Events and Spills Requirements and programs for the cleanup of deposited materials from nat ural events and spills onto paved roads are summarized in Table 6-21. Clark County Program More Stringent

Table 6- 21

Summary of Requirements a nd Programs for Cleanup of Natural Events and Spills onto Paved Roads

Area Rule # Requirements Clark County Public

Works • On average, cleanup of deposition from natural events and spills initiated within 15 to 30 minutes of the call for assistance during work hours and one hour or less after hours. Natural events such as major floods require additional time to mobilize. The magnitude of events varies widely, precluding characterization in terms of average cleanup time. Truck spills may require as little as one hour or as much as six hours for cleanup City of Henderson • When natural events result in high silt loadings, loaders and dump trucks are employed to remove the heaviest debris, followed by broom sweepers, followed by regenerative air sweepers. Truck spills are responded to within four hours and cleanup continues until the work is completed. Clark County,

Nevada

City of Las Vegas • The City of Las Vegas responds immediately to any large-scale storm event. Cleaning continues around

the clock until all storm-rela ted debris and sediment are
removed6-54 Table 6- 21

Summary of Requirements a nd Programs for Cleanup of Natural Events and Spills onto Paved Roads (continued)

Area Rule # Requirements City of North Las Vegas • The Roadway Maintenance Division begins response to storm events with sweepers and other necessary equipment immediately. All paved roadways impacted by storm events are swept within 48 hours following the event. Truck spills are responded to immediately during work hours and within one hour after hours Clark County,
Nevada (continued)
State of Nevada, Department of Transportation • Where exceptional events and spills occur, the District immediately applies all necessary manpower and equipment to mitigate the situation

Maricopa Co.,
Arizona Rule 310.01 § 306 • Cleanup of deposited material within 24 hours of discovery or prior to resumption of traffic on pavement where the pavement area has been closed to traffic

SCAQMD,
California Rule 1186(d)(1)

• Public agencies must begin removal of visible roadway accumulations on public paved roads within 72 hours
of notification

Maricopa County has adopted requirements for rapid cleanup of erosion- caused deposition of bulk materials onto paved surfaces. U nder these requirements, material cleanup must begin within 24 hours of identification or prior to reopening of a road to traffic where the road has been closed. These cleanup requirements are not limited to public roads; they apply to all paved surfaces. The SCAQMD has implemented rapid cleanup requirements under Rule 1186. The South Coast requirements ent ail initiating cleanup within 72 hours of discovery and apply only to public paved

roads.

In Clark County, all Public Works agencies have action plans or policies in place to facilitate the rapid cleanup of materials deposited on paved roads by storms and spills as summarized in T able 6-21. However major
storm events do occur t hat cause extensive damage and deposition of material on roadways. It is not technologically feasible for cleanup of major storm events to be completed withi n 24 hours in all situations due to the extent of damage experienced. Clark County Has Implemented an
Extensive Set of Requirements for
Construction Activities6-55 Clark County has also developed an extensive flood control system to minimize t he impact of natural events. As noted in Chapter 2, precip itation is limited in the Las Vegas Valley and averages only 4.13 inches per year. However, annual rainfall can vary substantially from year to year and from rainfall event to rainfall event. In general, rainfall events are infrequent but may result in intense precipitation. As a re sult, the infrastructure for handling storm water is necessarily robust to the extent that minor storms do not general ly result in significant off-site deposition of material. The flood control program for the area is directed by the Clark County Regional
Flood Control District. The District was created in 1986 and was charged with the res ponsibility of developing and implementing a comprehensive flood control master plan to alleviate flooding in Clark County. Funding has been provided through voter-approved sales taxes and General Obligation Flood C ontrol Bonds. Since 1987 the District has funded proj ects totaling over $600 million. Completed facilitie s include 45 detention basins and approximately 220 miles of channels, washes, and storm drains. Additionally, there are approximately $1.1

billion in flood control facilities identified in the Master Plan for future funding.

The natural event action plans or policies in place in Clark County and the cities of North Las Vegas, Las Vegas, and Henderson to deal with cleanup when a major storm event does occu r complement the work of
the Flood Control District. The plans entail mobilization of all available equipment from unaffected areas to the event location(s) and removal of heavy silt deposits as quickly as possible. Since completion of the flood control system to handle a 100- year storm is years out (pending an additional $1.1 billi on in funding), there is still the possibility of wi despread erosion and deposition from a major storm. The entities’ plans require quick response and focus maximum resources on the cleanup of roadways. However, ti me periods for initiating and completing cleanup of all silt deposits are not established since they may va ry significantly from storm

to storm.

The existing Clark County cleanup programs have proven effective in practice. In July 2000, a 100-year flood event which caused significant flooding and Clark County Experiences Limited Impacts from Erosion Deposition

Public Works Agencies Have Contingency Plans in
Place for Flood Events

Clark County Contingency Plans Are
Effective6-56 property damage occurred in the Las Vegas Valley. Public agencies expediti ously commenced cleanup of road debris in accordance with their response plans. During the two weeks following the event, while silt moisture was high, PM 10 concentrations declined. All storm water deposits were cleaned up before they became sufficiently dry to cause elevated PM 10 concentrations. Air quality standards were not
exceeded and monitored concen trations were normal for that time period. Therefore, Clark County believes that its programs for cleanu p of silt loading on paved roads are of equivalent st ringency to those in other

areas.

6.3.5 Unpaved Roads

The potential MSMs for paving or stabilizing unpaved
roads are identified and analyzed in the following

section.

6.3.5.1 Control Measures for Paving Or Stabilizing Unpaved Roads Requirements for paving or stabilizing unpaved roads in Maricopa County and Clark County are summarized in
Table 6-22. There were no other programs found for unpaved roads that were nearly as stringent as those implemented in these two areas.

Table 6- 22

Summary of Requirements for Pavi ng or Stabilizing Unpaved Roads

Agency Rule # Requirements

Clark County,

Nevada AQR Section 91.2.1

AQR Section 91.2.1.1

SIP Commitment

AQR Section 91.2.1.2 • Pave or apply and maintain dust palliatives to stabilize all new unpaved roads constructed after June 22, 2000

• Pave or apply and maintain dust palliatives to stabilize all

existing unpaved roads with ADT ≥ 150 by June 1, 2003

• Allocation of CMAQ funding to pave publicly owned and

maintained unpaved roads over a three-year period ending June 1, 2003

• Prohibition on construction of new unpaved roads or

alleys in public thoroughfares after June 22, 2000

City of Las Vegas • Commitment to pave all unpaved roads by the end of
20066-57 Table 6- 22

Summary of Requirements for Pavi ng or Stabilizing Unpaved Roads (continued)

Maricopa Co.,

Arizona Rule 310.01,
Section 303
SIP Commitment

SIP Commitment

SIP Commitment • Pave or apply and maintain dust palliatives to stabilize all existing unpaved roads with ADT ≥ 150 by June 10, 2004

• SIP commitment of public agencies to accept dedication

of certain privately owned unpaved roads

• Public agencies develop and implement programs to

stabilize unpaved roads

• Design standard restrictions on new unpaved roads

Both Maricopa and Clark County have developed comprehensive programs for stabilizing unpaved roads utilizing a combination of regulations and SIP commitments by the various jurisdictions to implement
control measures. There are a few distinctions between the two programs. Clark County Regulation 91 requires stabilization of all new unpav ed roads constructed after June 2000, and prohibits construction of new unpaved roads or alleys in public thoroughfares after June 2000. Maricopa Rule 310.01 does not have the new unpaved roads prohibition, but the requirement to stabilize unpaved roads with ADT great er than 150 by June 2004 would apply. Also, Maricopa depends on the jurisdictions to establish unpaved road restrictions through design standards or other locally adopted stabilization requirements which are identified in
their SIP commitments. Mo st jurisdictions have established requirements t hat limit or prevent the building of new unpaved roads, particularly roads serving new subdivisions and commercial and residential developments. Clark County Rule 91 requirements for new unpaved roads are more comprehensive as they specifically prohibit new unpaved roads and apply uniformly to all jurisdictions in

the nonattainment area.

Maricopa Rule 310.01 requires stabilization of existing unpaved roads with an ADT greater than 150 by June
2004. AQR Section 91 has the same stabilization requirement but with an earlier completion date of June 2003, and there is a SIP commitment to allocate Congestion Mitigation and Ai r Quality Improvement Program (CMAQ) funds to all jurisdictions as needed to6-58 pave publicly owned and maintai ned roads by that date. The Maricopa jurisdictions made a variety of SIP commitments ranging from the City of Phoenix commitment to pave all unpav ed roads regardless of ADT, to others like Maric opa County that committed to
meet the 2004 deadline to pave public roads with ADT greater than 150. The City of Las Vegas has made a commitment to pave all unpaved public roads regardless of ADT. Clark County also has an established Emissions Reduction Credit (ERC) program that, although not a SIP commitment, provides credits for paving roads below 150 AD T. Although it is not possible to quantify the overa ll impact of these various SIP commitments, the conclu sion is that the Clark County unpaved roads requirement is at least as stringent as Maricopa’s due to the earlier completion date established for paving roads over 150 ADT, the commitment to pave roads versus using other less efficient stabilization methods, and having programs
identified that will result in paving roads with less than
150 ADT.

Overall, the combined effects of AQR Section 91 and
the SIP commitments result in a program to reduce emissions from unpaved roads in Clark County that is at least as stringent as the program established in Maricopa County, and more stringent than any program implemented in other states.

6.4 MOST STRINGENT MEASURE SUMMARY

This Chapter provided doc umentation to satisfy the most stringent measure (MSM) requirement established by the CAAA, Section 188(e) as one of the requirements necessary to support a request for extension of the
Serious Area PM 10 attainment date beyond the established December 31, 2001 deadline.

Clark County followed U. S. EPA’s proposed policy for demonstrating the inclusi on of the most stringent measures in the SIP as pr ovided in Federal Register Notice 65 FR 19968, dated April 13, 2000. A five-step process for determining MSM, similar to that used for BACM determinations, was utilized. A complete analysis comparing the pot entially most stringent Clark County Requirements Are More Stringent than
Other States’

BACM/MSM6-59 measures that are included in the implementation plan of any state, or are achieved in practice in any state against the control measures implemented in the Las Vegas area was accomplished and fully documented. Through this analysis and comparison, it has been
demonstrated that the ma ximum degree of emission reduction that has been required or achieved from a source or source category in other SIPs or in practice in other states, and that can be feasibly implemented in the Las Vegas area, has been achieved by the implemented control measures.

The next chapter addresses the formal request for
extension of the 24-hour PM 10 NAAQS attainment date to December 31, 2006. Clark County Followed U. S. EPA’s Proposed

Policy in Evaluating
MSM7-1 

## CHAPTER 7 - REQUEST FOR EXTENSION OF THE
ATTAINMENT DATE FOR PM 10

7.1 INTRODUCTION

Clark County is requesting an extension of the
attainment date for the 24-hour PM 10 National Ambient Air Quality Standard (NAAQS). Section 188(e) of the 1990 Clean Air Act Amendments (CAAA) allows the U.S. EPA to extend the “Serious Area” attainment date up to five years upon application by the State if certain requirements are satisfied. The purpose of this chapter, in addition to formalizing the request for the extension, is to present supporting docu mentation that the extension request is warranted and CAAA requirements for granting an extension are met.

The PM 10 health standards are set at 150 micrograms per cubic meter ( μ g/m 3 ) for a 24-hour period average, and 50 μ g/m 3 for an annual average. The expected timeline for attaining these
health standards are differen t. In the case of the annual average health standard, attainment can be demonstrated by the CAAA-required date of December 31, 2001. T he 24-hour health standard is more problematic and attainment is not expected until 2006. A full five-year extension of the attainment date from 2001 to 2006 is requested for
the 24-hour health standard.

7.2 REQUIREMENTS FOR AN EXTENSION

Section 188(e) of the 1990 CAAA a llows the U.S.
EPA to extend the attainment date for a serious area for up to five years beyond 2001 if attainment by 2001 is impracticable. In addition to a formal request to the U.S. EPA for an extension, the requirements for an extension include the following:

1. Compliance with requirements and commitments applicable to the Las Vegas Valley in the State Im plementation Plan (SIP); Formal Request for
Extension of

Attainment Deadline

Extension of

Attainment Date Not Necessary for
Annual Standard

Extension of

Attainment Date to 2006 Requested for

24-Hour Standard

Clean Air Act Criteria for Granting

an Extension7-2 2. A demonstration that attainment by 2001 is impracticable;

3. Documentation that measures included in the SIP are as stringent as the Most Stringent Measures (MSM) that have been implemented by any state and/or achieved in practice in any state and are feasible for the area; and

4. A demonstration that the expected attainment date is the most expedi tious alternative date practicable.

7.3 COMPLIANCE WITH ALL REQUIREMENTS
AND COMMITMENTS

This State Implementation Plan (SIP) for the Las Vegas Valley complies wit h all requirements in sections 172 and 189 of the 1990 CAAA relating to
“serious” PM 10 nonattainment areas. Chapter 4 documents adoption and impl ementation of control measures designed to attain PM 10 National Ambient Air Quality Standards (N AAQS) at the earliest practicable date. These control measures constitute Reasonably Available Control Measures (RACM) and Best Available Control Measures (BACM) for all significant sources of PM 10 . Chapter 4 and corresponding appendices also present documentation on the publ ic hearing process, implemented control measures, and SIP

commitments.

Chapter 3 and Chapter 5, along with corresponding appendices, present emi ssions inventories, emissions projections, and attainment demonstration modeling in accordance with U.S. EPA regulations, guideline documents, and policies. A demonstration t hat attainment of the 24- hour standard by 2001 is impr acticable is presented
in the next section. The SIP Complies

with All Requirements for an

Extension7-3 7.4 ATTAINMENT OF PM 10 NAAQS BY 2001 IS
IMPRACTICABLE

Subsequent sections pr esent both quantitative and qualitative documentation that attainment of the 24-

hour PM 10 NAAQS by 2001 is impracticable. PM 10 emission estimates and projections of emissions
and concentrations for 2001 are derived from the proportional rollback approach, which was discussed at length in Chapters 3, 4, and 5. The implementation schedule for control measures and expected 24-hour concentrations in 2001 are
discussed below.

Since PM 10 in the Las Vegas Valley is dominated by geologic materials from fugitive dust area sources, the focus of this SIP has been on the
control of dust from t he following significant area sources: disturbed open areas, construction activities, paved roads, and unpaved roads. Controls on these sources are implemented through the newly adopted Se ctions 90, 91, 92, 93, and 94 of the Clark County Health District’s Air Quality Regulations. Thes e regulations are all in effect as of January 1, 2001.

The emission reductions resulting from the regulations are sufficient to achieve attainment of

the annual PM 10 Standard by the CAAA-established deadline. However, addition al time is necessary to
achieve the reductions needed to attain the 24-hour
standard as detailed below.

As described in the SIP Commitments Section of Chapter 4, the Health District has committed to hiring 15 additional staff in order to implement and enforce the new regulations. A ten-member compliance team will be formed to focus on Sections 90, 91, 92, and 93, while five new staff

members will be added to strengthen the existing construction activities programs and to implement Section 94 requirements. The process of funding, hiring, training, and utilizi ng the additional staff has already begun, and will be completed during calendar year 2001. Fugitive Dust
Sources Dominated

the PM 10 Emission Inventory

New Enforcement
Staff Will be Hired
and Trained in 20017-4 The control measure effectiveness values utilized in this SIP are predicated on this schedule. The
Overall Control Measure Reductions column in Table 4-14 reflects the significant increase in
control measure effect iveness from 2001 to 2002
that will be realized from the work activities of the
additional staff. Earlie r realization of these reductions is not practicable due to the time required to hire and train new staff to the proficiency level needed to effectively implement the additional dust control programs.

The control measure for unpaved road dust as described in Chapter 4 prohibits the construction of new unpaved roads, and a SIP commitment has been made to establish a schedule to pave all existing publicly owne d unpaved roads with an ADT of 150 or greater by June 30, 2003. Clark County and the cities of Las Vegas, North Las Vegas, and Henderson have obligated over $25 million in Congestion Mitigation and Air Quality (CMAQ) funds (including local matc h) over the next three years for the paving program. The funding commitment will support completing approximately one-third of the total pavi ng requirement each year from 2001 through 2003. The overall control reduction percentage from this control measure will increase from 22 percent in 2001 to 65 percent in
2003. The maximum benefit that will be realized at the end of 2003 cannot pr acticably be achieved earlier due to funding limitations in each year.

Chapter 5, utilizing the im plementation schedule for controls and expected emission reductions that will be achieved, provides quantitative documentation
that PM 10 emissions and corresponding concentrations are not sufficiently reduced to allow
for attainment of the 24-hour PM 10 health standard by 2001. More specifically , valley-wide proportional rollback modeling for 2001 and the resulting inventory presented in A ppendix L, Table L-21, Valley-wide 2001 24-Hour Inventory, demonstrate that the projected 24-hour PM 10 concentrations in 2001 will be 209 micrograms per cubic meter after controls are applied. Al though this represents a significant reduction from the projected design Unpaved Roads with
Greater Than 150

ADT Will be Paved by the End of 2003

The 24-Hour NAAQS
Cannot be Attained
in 20017-5 day concentration of 281 μ g/m3, it is still far short of

the 150 μ g/m3 standard. The 150 μ g/m 3 24–hour standard cannot practicabl y be achieved by the end
of 2001.

7.5 DOCUMENTATION ON INCLUSION OF MOST STRINGENT MEASURES (MSM)

Chapter 6 provides the MSM analysis in accordance with U.S. EPA’s proposed policy for satisfying the Section 188(e) requirements. Documentation was pres ented showing that the

PM 10 controls contained in this State Implementation Plan for t he Las Vegas Valley are as stringent as those in cluded in implementation plans of any state, or achieved in practice in any state, that can feasibly be implemented in the Las Vegas Valley.

Chapter 4 documented the control measure development and implementation process that
resulted in the best available control measures (BACM) being applied to control significant PM 10 sources. The process for identifying MSMs was similar to BACM except fo r one additional step that compared potential MSMs with those measures adopted for the Las Vegas Valley.

The MSM analysis in Chapter 6 demonstrated that the maximum degree of emission reduction that has been required or achieved from a source or source category in other SIPs or in practice in other states, and that can be feasibly implemented in the Las Vegas area, has been achieved by the implemented control measures.

7.6 DEMONSTRATION THAT 2006 IS THE MOST
EXPEDITIOUS ALTERNATIVE DATE
PRACTICABLE FOR ATTAINMENT OF THE 24-
HOUR PM 10 NAAQS

In order to determine if 2006 is the most expeditious alternative date for attainment of the RACM/BACM Adopted in Clark County are the Most

Stringent Control

Measures7-6 24-hour NAAQS, Chap ter 5 presented a Reasonable Further Progress (RFP) Analysis for 2003. The following sections discuss the results of the RFP analysis and pres ent the expected 24-hour concentrations in the proposed attainment year of
2006.

7.6.1 Expected 24-Hour Concentrations in 2003

In Section 7.4, information was provided to document the impracticability of attaining the 24-hour standard by 2001. It was noted that control measure effectiveness would improve significantly
after 2001 when the commitment to increase staffing at the Health Distric t’s Air Quality Division is completed. Unpaved road emissions would be reduced through the program to pave roads over a three-year period from 2001 to 2003, with the maximum reduction rate achieved by the end of 2003. An analysis of the progress towards

attainment was conduct ed for the end of 2003 to quantify the emission reductions achieved. The results of the Reasonable Further Progress Analysis are depicted in Figure 5-2 which shows projected tons of emissions for 2003 and 2006 after quantifying emission reductions which result from the implementation of the committed control

measures.

The projected 2003 emissions level of 277 tons represents a reduction of more than 70 percent from the base year 1998 em issions. Additional reductions of approximatel y 25 percent are required to reach the attainment level of 206 tons per day. The greater-than-50 percent reduction of emissions toward the attainment level by 2003 does
demonstrate reasonable furt her progress, and also illustrates the impracti cability of achieving
attainment earlier than 2006.

Appendix M further docum ents the progress toward
attainment with a detai led breakdown of the inventory projections for 2003. The overall control measure reductions applie d to the 2003 inventory are the same as applied to the 2006 emission inventory except for unimproved shoulders Reasonable Further Progress was
Demonstrated for
20037-7 on paved roads, which will not be fully implemented by 2003. These control measure reductions are
described in detail in Appendix L. SIP commitments for paving unpaved shoulders are
described in Section 4.8. Participating state and
local entities are committ ed to prepare a plan that will identify and prioritize paving requirements for unpaved shoulders as well as unpaved roads with an ADT of less than 150. Beyond fiscal year 2003, and after completion of the program to pave unpaved roads with an ADT of greater than 150, CMAQ funds will be allocated as necessary to complete each entity’s plan for stabilizing shoulders and paving unpaved roads by December 31, 2006.

Chapter 4 addresses the process that will be followed by public works agencies to develop a detailed plan for the st abilization of unimproved shoulders on paved roads. This program will be accomplished with CMAQ funds after the commitment to pave unpaved roads is completed in 2003, with the paving of t he unstable shoulders to be completed by the end of 2006.

7.6.2 Expected 24-Hour Concentrations in 2006

and the Attainment Demonstration

The expected 24-hour concentrations on a valleywide and micro-area bas is are presented in Chapter 5 for the 2006 attainment year. The proportional rollback model ing indicates that 24-hour concentrations on a valley-wide and microarea basis are below the 24-hour PM 10 NAAQS (150 micrograms per cubic meter). Combined with the need for three years of air quality monitoring data to account for year-to-year variability in meteorological condit ions, the attainment demonstration in Chapter 5 is clear documentation that 2006 is the most exp editious alternative date
for attainment of the 24-hour PM 10 standard.

7.7 SUMMARY

This chapter is a formal request for an extension of
the attainment date for the 24-hour PM 10 NAAQS. A five-year extension of t he attainment date from 2006 is the Most Expedient Date to
Attain the 24-Hour
Standard7-8 2001 to 2006 is request ed for the 24-hour PM 10 NAAQS. Section 188(e) of the 1990 Clean Air Act Amendments (CAAA) allo ws the U.S. EPA to
extend the “Serious Area” a ttainment date up to five years from 2001 upon applicat ion by the state if certain requirements are sati sfied. Documentation of the following requir ements were provided:

1. A demonstration that attainment by 2001 is impracticable;

2. Compliance with requirements and commitments applicable to the Las Vegas Valley in the SIP;

3. Documentation that the control measures
included in the SIP ar e as stringent as the most stringent measures in the implementation plan of any state and/or achieved in practice in any state that are feasible for the area; and

4. A demonstration that the 2006 attainment date is the most expe ditious alternative date practicable.

All of the issues discussed in this Chapter
underscore the need and reasonableness of a fiveyear extension of the a ttainment date for the 24-

hour PM 10 NAAQS. Formal Request for

a Five-Year
Extension of the
Attainment Date for

the 24-Hour PM 10 NAAQS