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# Assessment of Qualification for Treatment under the Arizona Natural and Exceptional

Events Policy for the High Particulate (PM 10 

# ) Concentration Events in the

Phoenix Area on March 14, 2008

Background

The Arizona Department of Environmental Quality (ADEQ)

issues Dust Control Action Forecasts as part of the Natural

Events Action Plan for the Phoenix area. On Thursday, March

13, 2008, in response to a tightening pressure gradient ahead

of a low pressure system and associated cold front

approaching Arizona from the west, ADEQ air quality

forecasters issued the Maricopa County Dust Control Action

Forecast which called for a moderate risk of wind-blown dust

for Friday, March 14 th 

## . In addition, ADEQ air quality

forecasters issued a PM 10 

## Health Watch for March 14, 2008,

due to the possibility of strong winds and blowing dust

throughout the Maricopa County area. The forecasts and

advisories satisfy the requir ement in 40 CFR 51.930(a)(1).

The forecast for March 14 th 

## called for strong winds capable of

producing wind-blown dust. This potential wind-blown dust

event equated to a moderate risk of exceeding the PM 10 

## National Ambient Air Quality Standards (NAAQS) in

Maricopa County. During the late morning / early afternoon

hours of March 14 th 

## , strong, gusty winds moved into the

Phoenix Metro area from the west. All appropriate State

Implementation Plan (SIP) control measures were in place

during the event demonstrating, per 40 CFR 50.1(j), that the

event “is not reasonably controllable or preventable.” A

discussion of commonly employ ed Best Available Control

Measures (BACM) for dust in Maricopa and Yuma counties can be found in “High Wind Exceptional Events and Control

Measures for PM 10 

## Areas” (see “References”).

Strong winds were observed th roughout portions of Maricopa

County and the Phoenix Metro area on March 14, 2008. The

initialization of the wind-blown dust event is evident in the

Phoenix visible camera images as well as the Arizona

Meteorological Network (AzM ET), Maricopa County (MC),

and National Weather Service (NWS ) monitors (see Fig. 1).

Gusty winds greater than 20 and 30 mph were reported

between the 10:00 a.m. and 5:00 p.m. hours at several

Phoenix area monitoring locati ons. In addition, Phoenix

Goodyear Airport reported redu ced visibility and a wind gust

of 43 mph during the event.

This significant event brought elevated ambient

concentrations of PM 10 

## to the Phoenix area. Due to the spatial

variability of PM sources both within and outside of the

Phoenix urban core, the PM 10 

## NAAQS was only exceeded at

the West 43 rd 

## Ave. monitor operated by Maricopa County (see

Section 2 for more detail). The fact that ambient

concentrations exceeded the NAAQS satisfies the criteria in

40 CFR 50.1(j) that the event “affects air quality.”

The following are the key PM 10 

## monitor readings for the

monitors examined in this report:

Monitor (Operator/Type) AQS ID 24-hr Avg PM 10 

### 1-hr Max PM 10 

### Max Time Flag**

PHOENIX METRO AREA

West 43 rd 

### Ave (MC/TEOM) 04-013-4009* 251 1286 1300 RJ

South Phoenix (MC/TEOM) 04-013-4003* 119 461 1300 None

Durango Complex (MC/TEOM) 04-013-9812* 92 310 1300 None

Greenwood (MC/TEOM) 04-013-3010* 71 151 1300 None

Higley (MC/TEOM) 04-013-4006* 51 140 0700 None

West Phoenix (MC/TEOM) 04-013-0019* 57 126 1300 None

Central Phoenix (MC/TEOM) 04-013-3002* 69 231 1300 None

JLG Supersite (ADEQ/TEOM) 04-013-9997* 40 62 1300 None

Coyote Lakes (MC/TEOM) 04-013-4014* 47 107 0700 None

* EPA Air Quality System Identification Number

** 24-hr PM 10 concentration influenced by natural or exceptional event to be flagged

Type Abbreviations: TEOM – Tapered Element Oscillating Microbalance Monitor (Continuous monitor)



## The preliminary findings from this analysis were presented at

stakeholders meetings on Nove mber 19, 2008, and March 19,

2009, in Phoenix, Arizona. Following the stakeholders

meetings, ADEQ supplemented and finalized the analysis and a public comment period was held from October 15, 2009

through November 13, 2009. This finalized document and

any comments received are being submitted to EPA to satisfy

the requirements in 40 CFR 50.14(c)(3)(i).HrT(F)VRDustSpdGustDir HrT(F)VRDustSpdGustDir HrT(F)VRDustSpdGustDir Hr11 0 0 0 0 N/A1 0 0 0 0 N/A1 63 10 6 6 E 126.12 0 0 0 0 N/A2 0 0 0 0 N/A2 62 10 6 6 E 228.93 0 0 0 0 N/A3 0 0 0 0 N/A3 60 10 6 6 E 322.240000N/A40000N/A4591077E428.45 0 0 0 0 N/A5 0 0 0 0 N/A5 59 10 5 5 E 564.66 0 0 0 0 N/A6 0 0 0 0 N/A6 57 10 8 8 Ewithw/o61557 0 0 0 0 N/A7 0 0 0 0 N/A7 57 10 0 0 NMonitor:Event Event71468 61 60 9 9W8 0 0 0 0 N/A8 61 10 0 0 N1-W43RD2516981349 66 40 9 9 SW9 0 0 0 0 N/A9 65 10 6 6 E 918810 70 30 7 7W10 70 20 15 23 SW10 70 10 5 5 SW1032911732066SW1173201623SW1177101120W> NAAQS< NAAQS113551282151429W1279201823W1279102129W1210521 86 10 18 34W1 81 20 20 26W1 81 10 21 30W112702 86 15 25 43W2 82 20 21 26W2 82 10 25 30W212863 84 20 14 23W3 82 20 20 25W3 82 10 23 23W33744 84 20 17 17 SW4 81 20 14 23 SW4 82 10 17 24W487582401717SW582201121W581101323W557.1wnd@3m agl/Dir correctedtotrue north681401111W681201111SW680101414W623.6HIGHLIGHTINGCol.Parameter7 75 40 6 6 *VR7 75 20 5 5W7 77 10 7 7W737.1Max Wind T(F)Temp.(Deg. F.)8 0 0 0 0 N/A8 0 0 0 0 N/A8 76 10 9 9 SW840.8> 15 mph RHRel Humidity%970201111SW90000N/A972101111SW986.4>25mphRnRain(Inches/hr)10 0 0 0 0 N/A10 0 0 0 0 N/A10 73 10 10 10W1093.1HR - Time (End) SpdAvgSpeed mph11 0 0 0 0 N/A11 0 0 0 0 N/A11 69 10 10 10W1173.4A.M. MaxMax Speed mph120000N/A120000N/A12671077W1272.9P.M.DirWind Dir.(from)Hr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir03/14/2008 - 12z 03/15/2008 - 12z 03/14/2008 - 12z 03/15/2008 - 12z1 69265 9SW1 63631 4W1 70195 12 SW2 68286 10 SW2 64663 10 SW2 68284 11 SW3662258W36643611W36722411SW4 64285 7SW4 62301 7SW4 64243 8SW5586439NE5586326E5603516EYrSea6 571545 8 E 6 56672 6 E 6 58462 5E5 87 571454 11 E 7 56682 8 E 7 56612 6E9 98 591332 6 E 8 621322 4 E 8 59821 4 SE11 119 641872 5 NE 9 71800 3 NE 9 65492 11 SW15 1310 733287 23W10 741178 20W10 70759 22 SW19 1911 7735512 24W11 769013 24W11 736612 23W29 28127910511631W12782161529W1276721128W44461 82127018 36W1 8020515 34W1 7910613 28W65 632 83128619 36W2 8131019 36W2 8112514 31W91 823 8437414 31W3 8212715 41W3 8112114 36W121 1074 848712 26W4 843213 27W4 813611 25W139 125 3/14 - 10:45AM 3/14 - 11:45AM 3/14 - 1:45PM 3/14 - 2:45PM5 835712 24W5 832812 30W5 802511 24 SW157 1346 812310 20W6 81279 19W6 80279 21W192 1947 77376 14W7 77356 14W7 78354 10W227 22087540815SW87367714W87550415SW3133139 748611 22 SW9 72929 18 SW9 73665 18 SW1072931022SW107089716W107065414W11 67736 11W11 66816 11W11 68675 13W126672511SW12628047W126766510W3/14-10:45AM3/14-11:45AM3/14-12:45PM3/14-1:45PM3/14-2:45PMHr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir Hr T(F) RH Rn Spd Max Dir Hr T(F) RH Rn Spd Max Dir1 58822 6 N 1 63433 7 E 1 63 34 -3 6 SE 1 53 49 - 5 6 SE2 57682 6 N 2 61393 6 E 2 61 35 -3 6 SE 2 54 44 - 5 7 SE3 55582 5 N 3 59412 6 E 3 60 34 -3 6 E 3 56 36 - 5 7 E4 53243 8 N 4 58424 7 E 4 60 33 -3 5 E 4 55 38 - 6 8 E5 52322 6 N 5 57362 5 E 5 58 34 -3 6 E 5 52 45 - 6 8 SE3/14 - 10:45AM 3/14 - 11:45AM 3/14 - 12:45PM 3/14 - 1:45PM 3/14 - 2:45PM6 51453 7 NE 6 56364 6 E 6 58 34 -3 6 E 6 51 48 - 5 8 E7 50502 7 N 7 56333 6 E 7 58 33 -5 7 SE 7 53 41 - 5 7 E8 541061 5 N 8 64382 6 SE 8 60 33 -4 7 SE 8 55 42 - 5 8 SE9 66771 4 NE 9 71543 6 E 9 64 29 -4 7 SE 9 60 43 - 7 10 SE10 71551 6N10 76552 17 SW10 69 27 -3 6 SE 10 67 30 - 7 10 S11 76351 10 SW11 7810512 25W11 73 22 -2 6 N 11 72 23 - 7 12 SW127922621SW12801271530W127812-918W127615-1020W1 815211 25W1 8114916 30W1 79 10 -11 21W1 78 10 - 13 20W2 826111 30W2 8223020 37W2 81 7 -13 23W2 80 9 - 13 25W3 829814 32W3 8215919 37W3 81 7 -12 23W3 80 9 - 13 21W3/14 - 10:45AM 3/14 - 11:45AM 3/14 - 12:45PM 3/14 - 1:45PM 3/14 - 2:45PM4 823112 28W4 833314 28W4 82 9 -9 18W4 80 9 - 12 20W5 821710 26W5 832813 29W5 81 11 -9 16W5 79 10 - 14 23W6 811310 21W6 813112 24W6 80 11 -8 14W6 77 11 - 12 19W7 74134 14W7 77307 16W7 78 12 -4 10W7 73 13 - 8 15W8 66410 2NW8 74476 16W8 75 12 -4 10 SW8 69 14 - 5 9W9 62440 4S9 73647 16 SW9 73 11 -5 9SW9 65 15 - 5 9W10 61320 4 NE10 71776 15W10 73 11 -4 9SW10 64 16 - 6 11W11 57330 3N11 69758 19W11 70 13 -3 9SW11 63 16 - 5 10 SW12554224N126874816W124365-37E126020-711SWPrepared by S. Kendall, A. Juniel, B. Busby and B. Paris/ ADEQ 3/19/09SUMMARY OF EVENTA low pressure system causedstrong west-southwesterlywinds on 3/14 throughoutportions of the valley. SkyHarbor Int'l Airport reportedgusts to 30 m.p.h. whileGoodyear Airport had gusts ashigh as 43 m.p.h. These gustywinds coincided with elevatedPM10 levels at West 43rd Ave.

(looking northeast)

SOUTH MOUNTAIN CAMELBACK MTN (looking south)Historical DistributionAZMET Monitoring LocationsSee http://ag.arizona.edu/azmet/Figure 1.Key Data forEvent of March14, 2008KEYPM10 &WIND PLOTECAWx IMAGERYWIND &PM10DATAHISTDISTPHX VIS.CAMERASNWS-Phx Sky Harbor

NWS-Phx Sky HarborNWS-Goodyear AirportMC - WEST PHOENIX75%2.5%

22-Queen Creek50%5%PHX METRO - MESA1.0%Column IndexMONITORS:Freq. (looking south)

NWS-Glendale Municipal Airport

NWS-Goodyear AirportNWS-Glendale Airport0.5%Min25%24-Hr. Avg PM1010%MC - COYOTE LAKESEvent Contrib. AnalysisHourly PM10Conc. (μg/m3)1-W43RDCum. Mon 1MONITORS:Pink=Event Contrib.Conclusion: Asshown above,the PM10concentration wouldhave been below theNAAQS "BUT FOR"the eventcontribution (hourshighlighted in pink).90%Max99.5% WHITE TANK MTN (looking west)

ESTRELLA MTNConclusion: Flagged Value is exceptional

MC - COYOTE LAKES MC - WEST PHOENIX127530 (112.31Wx33.67N) 16329 (112.05Wx33.46N)MC - CENTRAL PHOENIXAZMET -251in nature (ie greater than 95% of all data)

29-MesaAZMET -

MC - CENTRAL PHOENIXSOUTHEAST PHOENIX95%97.5%FlaggedValue99.0%5-Yr. Dist. of Values (μg/m3)Sea - Data for Springseason only(5-Yrs)Yr - All Data(5-Yrs)1-W43RD500 mb Analysis Charts3/14 - 12:45PM16477 (112.14Wx33.48N)NOAA - Surface Analysis Maps16659 (112.14Wx33.41N)MC - WEST FORTY THIR

MC - WEST FORTY THIR MC - DURANGO COMPLEX16375 (112.12Wx33.43N)MC - DURANGO COMPLEXWest 43rd - PM 10 vs. Wind Speed0200400600800100012001400 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:003/14/2008

PM Concentration ( μ g/m^3)051015202530354045 Wind Speed (mph)PM10Max Wind

## Assessment of March 14, 2008 event (Cont.)

- 4 - 

# Assessment under the Technical Criteria Document (TCD)

1. Properly qualify and validat e the air quality measurement

to be flagged. As this was not a filter sampling date (1-in-6

run day), only data from the continuous analyzers were

examined. The air quality monitoring data were reviewed by

the agency responsible for op eration of the monitor. All

hourly PM 10 

## readings from the West 43 rd 

## Ave. monitoring site

were valid for March 14 th 

## . Audits of the analyzers revealed

operations were within acceptable tolerance. No local sources

were reported as signi ficantly contributing to the air quality

episode. Exceed ances of the NAAQS were recorded at the

West 43 rd 

## Ave. monitoring site operated by Maricopa County.

2. Review suspected contributing sources. The NWS,

AzMET, and MC surface data for Arizona, along with the

visible camera images in Phoenix, provide a good explanation

of the meteorological conditions that were in place on March

14 th 

## . Strong westerly winds were occurring in the Phoenix

area due to a low pressure system approaching from the west

with a cold front situated west of Arizona. The plot of hourly

PM 10 

## concentration data and max winds in the upper right

corner of Figure 1 confirms the nearly identical timing of

elevated PM 10 

## and strong wind gusts at the West 43 rd 

## Ave.

monitor. The high wind event was a regional phenomenon

that affected the entire Phoenix Metro area. However, PM

sources are highly variable across space; therefore, the

locations of higher PM 10 

## concentrations (namely the Salt

River channel) are likely an indication that these locations (or

areas upwind of these locations ) contain greater sources of

PM than other locations with in the Phoenix Metropolitan

area. While no specific source allocation can be determined

for this particular day, the 2005 ADEQ revised PM 10 

## SIP for

the Salt River area (attached) contains modeled source

contributions on high wind days (see section 4.2 – Source

Categories). Results estimate that approximately 76% of

PM 10 

## concentrations can be attr ibuted to windblown dust, of

which 21% is from agricultural fields, 15% from alluvial

channels, and 21% from vacant lots. It is not clear whether

similar source alloca tions can be assumed for this March 14,

2008, high wind event.

3. Examine all air quality monitoring information. Data from

all monitors in the network we re reviewed. Monitors from

the affected areas are summarized in the table in the

Background section of this asse ssment. Pursuant to 40 CFR

50.14(c)(3)(iii)(C), the “Historical Distribution” Table in

Figure 1 has been included to demonstrate that the event is

associated with a measured concentration in excess of normal

historical fluctuations, including background (i.e.,

concentrations greater than the 95 th 

## percentile). Additionally,

the winds associated with the elevated PM 10 

## concentrations

may be characterized as unusual as described in “Impact of Exceptional Events’ ‘Unusual Winds’ on PM 10 

## Concentrations” (see “References”).

4. Examine the meteorological conditions before and during

the event. The meteorological data are summarized in Figure

1. The wind data are highlighted yellow if the max wind

speed in the hour exceeds 15 mph and orange if it exceeds 25

mph. As can be seen in Figure 1, wind speeds did not pick up

in central Arizona until approximately 10:00 or 11:00 a.m.,

when several stations reported gusty winds that approached

30 and even 40 mph at times. Th is timing corresponds to the

onset of elevated PM 10 

## concentrations recorded at the West

43 rd 

## Ave. monitoring site, which remained elevated through

the afternoon hours until the winds decreased to below 20

mph.

5. Perform a qualitative attr ibution to emission source(s). All

evidence indicates the elevated PM 10 

## concentrations in the

Phoenix area can be attributed to soil emissions that were

transported over portions of the Phoenix Metro area in

Maricopa County. No source specific emission allocation is

possible based on the data available for analysis. The hourly

concentration data do not s how any significant source other

than the wind-blown dust event occurring on March 14, 2008.

Observational reports of reduced visibility throughout

portions of Phoenix are further proof that the elevated PM 10 

## concentrations were attributed to soil emissions transported

by high winds. These reports, in addition to the visual

evidence of reduced visibility seen in the lower right portion

of Figure 1, provide proof that the elevated PM 10



## concentrations in Phoenix can be attributed to soil emissions.

6. Estimation of Contribution from Source or Event. The

primary source appears to be wind-blown dust over central

Arizona for which there is not an effective or efficient method

to estimate the relative contributions from specific sources.

The demonstration analysis contained in this report

establishes the linkage betwee n the measurements to be

flagged and the event, thus sa tisfying the requirement in 40

CFR 50.14(c)(3)(iii)(B). Pursuant to 40 CFR

50.14(c)(3)(iii)(D), the “Event Contrib. Analysis” Table in

Figure 1 has been included to demonstrate that there would

have been no exceedance or violation but for the event (i.e.,

the contribution during the event overwhelmed the 24-hour

average).

7. Determination that a Natural or Exceptional Event

Contributed To an Exceedance. Based on this analysis, the

event satisfies the requirement in 40 CFR 50.1(j) that the

elevated concentration at West 43 rd 

## Ave. was attributed to a

natural event.



# Conclusion

Transport of dust from soils by high winds . The elevated

PM 10 

## event on March 14, 2008, in Maricopa County was the

result of the transport of dust and soils from high winds that

suspended natural soils and soils from areas where Best

Available Control Measures are in place and should be

flagged for air quality planning purposes. The “high wind” (RJ) flag should be applied to the monitor readings indicated

in the table at the beginning of this report, as the monitor

would have been below the NA AQS but for the contribution

of the event.

# ATTACHMENTS AND REFERENCES

FOR EXCEPTIONAL EVENTS ANALYSIS

The following are supplemental materials helpful in understanding the exceptional

event summarized in the main report. In addition, the reader is referred to the

following references.

REFERENCES

Arizona Department of Envi ronmental Quality (ADEQ), Air Quality Exceptional and

Natural Events Policy , Policy Number 2009.002 (April 28, 1999; revised January 10,

2006 and June 22, 2007).

Arizona Department of Environmental Quality (ADEQ), Technical Criteria Document

for Determination of Natural Exceptional Events for Particulate Matter Equal to or Less

Than Ten Microns in Aerodynamic Diameter (PM 10 

# ) (May 31, 2000).

Arizona Department of Environmental Quality (ADEQ), Technical Criteria Document

for Determination of Na tural and Exceptional Events (December 12, 2005).

Arizona Department of Environmental Quality (ADEQ), Impact of Exceptional Events

‘Unusual Winds’ on PM 10 

# Concentrations (October 14, 2009).

Arizona Department of Envi ronmental Quality (ADEQ), High Wind Excep tional Events

and Control Measures for PM 10 

# Areas (October 14, 2009).

Environmental Protection Agency (EPA), The Treatment of Data Influenced by

Exceptional Events (Exceptional Event Rule) , 73 FR 70597; 40 CF R Parts 50 and 51

(November 21, 2008).

## VERY UNHEALTHY (201-300)

UNHEALTHY (151-200)

UNHEALTHY FOR SENSITIVE GROUPS (101-150)

MODERATE (51-100)

GOOD (0-50)

For more information visit:

http://www.epa.gov/airnow/aqibroch

*LINK TO EXCEEDANCE & HEALTH STATEMENT INFO FOR THE 2006-07 & 2007-08 FORECAST SEASONS* 

# AIR QUALITY FORECAST FO R FRIDAY, MARCH 14, 2008

This report is updated by 1:00 p.m. Sunday thru Friday and is valid

for areas within and bordering Maricopa County in Arizona

* O3 = Ozone CO = Carbon Monoxide PM-10 = Particles 10 microns & smaller PM-2.5 = Particles smaller than 2.5 micro ns



### *“ Ozone Health Watch ” means that the highest concentration of OZONE may approach the federal health standard.

“ PM-10 or PM-2.5 Health Watch ” means that the highest concentration of PM-10 or PM-2.5 may approach the federal health standard.

“ High Pollution Advisory ” means that the highest concentrati on of OZONE, PM-10, or PM-2.5 may exceed the federal health standard.

“ DUST ” means that short periods of high PM-10 concentrati ons caused by outflow from thunderstorms are possible. 

## FORECAST

DATE

NOTICES

(*SEE BELOW

FOR DETAILS)

AIR POLLUTANT 

# YESTERDAY

WED 03/12/2008

NONE

Highest AQI Reading/Site

(Preliminary data only) 

# TODAY

THU 03/13/2008

NONE 

# TOMORROW

FRI 03/14/2008

PM-10 HEALTH

WATCH 

# EXTENDED

SAT 03/15/2008

NONE



# O3* 42

APACHE JUNCTION 

## 51

MODERATE 

## 47

GOOD 

## 35

GOOD



# CO* 16

GREENWOOD 

## 15

GOOD 

## 11

GOOD 

## 09

GOOD



# PM-10* 58

WEST FORTY THIRD 

## 68

MODERATE 

## 94

MODERATE 

## 74

MODERATE



# PM-2.5* 38

PHOENIX SUPERSITE 

## 31

GOOD 

## 27

GOOD 

## 24

GOOD

## Health message for Thursday, Mar 13: Unusually sensitive people should consider

reducing prolonged or heavy exertion.

Health message for Friday, Mar 14: Unusually sensitive people should consider

reducing prolonged or heavy exertion.

Synopsis and Discussion

A PM-10 HEALTH WATCH HAS BEEN ISSUED FOR FRIDAY MARCH 14



## Major changes in local weather conditions are on tap the next few days as the mid-latitude storm track

migrates south over the area. Wester ly winds aloft over the Valley are a dvertised to reach 50+ mph at the

10K’ level and near 100 mph at the 18K’ level on Friday; since the predicted mixing depth is near 9K’,

some of this momentum will have an avenue for reaching the surface. Areas of blowing and suspended dust

are therefore likely as is the poten tial for transported dust from desert areas upwind of the metro area.

Since PM-10 (coarse particle) levels may approach unhealthy levels, a PM-10 Health Watch has been

issued for Friday. After a very breezy day on Saturd ay, an upper level trough and surface cold frontal

passage are forecast to occur on Sunday and will be accompanied by showers and a few thunderstorms –

along with gusty winds and much colder temperatures. -Reith

MONITORING SITE MAPS: STATIC MAP

– http://www.azdeq.gov/environ/air/monitoring/images/winter.jpg

INTERACTIVE MAPS – http://aqwww.maricopa.gov/AirMonitoring/SitePollutionMap.aspx

http://www.airnow.gov /



# POLLUTION MONITOR READINGS FOR WEDNESDAY, MARCH 12, 2008



# O3 (OZONE)

SITE NAME MAX 8-HR VALUE (PPB) MAX AQI AQI COLOR CODE

Apache Junction 54 42

Blue Point 42 33

Central Phoenix 43 34

Fountain Hills 49 38

North Phoenix 32 25

Phoenix Supersite 47 37

Pinnacle Peak 45 35

South Phoenix 50 39

South Scottsdale 43 34

West Phoenix 45 35



# CO (CARBON MONOXIDE)

SITE NAME MAX 8-HR VALUE (PPM) MAX AQI AQI COLOR CODE

Buckeye 0.3 04

Central Phoenix 0.8 09

Dysart 0.4 05

Glendale 0.6 07

Greenwood 1.4 16

Mesa 0.5 06

North Phoenix 0.6 07

Phoenix Supersite 1.2 14

South Phoenix 0.8 09

South Scottsdale 0.4 05

Tempe 0.7 08

West Chandler 0.5 06

West Indian School 1.3 15

West Phoenix 1.0 11

# PM-10 (PARTICLES)

SITE NAME MAX 24-HR VALUE (ug/m3) MAX AQI AQI COLOR CODE

Buckeye 48 44

Central Phoenix 35 32

Coyote Lakes 22 20

Durango 56 51

Greenwood 48 44

Higley 42 39

Maricopa (Pinal County) 70 58

Phoenix Supersite 31 29

Queen Creek (Pinal County) 54 50

South Phoenix 46 43

West Forty Third 70 58

West Phoenix 40 37



# PM-2.5 (PARTICLES)

(Some data derived from light-scattering equipment)

For maps go to: http://www.airnow.gov /

SITE NAME MAX 24-HR VALUE (ug/m3) MAX AQI AQI COLOR CODE

Durango 11.2 36

Dysart 3.4 11

Estrella Mountain Park 6.1 20

Phoenix Supersite 11.8 38

Vehicle Emissions Lab NOT AVBL NOT AVBL NOT AVBL

West Phoenix 11.4 37



# LOCAL AIR POLLUTANTS IN DETAIL

O3 (OZONE) :

Description – This is a secondary pollutant that is formed by the reaction of other primary

pollutants (precursors) such as VOCs (v olatile o rganic c ompounds) and NOx (N itrogen Ox ides)

in the presence of heat and sunlight.

Sources – VOCs are emitted from motor vehicles, chemical plants, refineries, factories, and

other industrial sources. NOx is emitted from motor vehicles, power plants, and other sources of

combustion.

Potential health impacts – Exposure to ozone can make people more susceptible to respiratory

infection, result in lung inflammation, and aggr avate pre-existing respiratory diseases such as

asthma. Other effects include decrease in lung fu nction, chest pain, and cough.

Unit of measurement – Parts per billion (ppb).

Averaging interval – Highest eight-hour period within a 24-hour period (midnight to midnight).

Reduction tips – Curtail daytime driving, refuel cars an d use gasoline-powered equipment as late

in the day as possible.

# CO (CARBON MONOXIDE) :

Description – A colorless, odorless, poisonous gas formed when carbon in fuels is not burned

completely.

Sources – In cities, as much as 95 percent of all CO emissions emanate from automobile exhaust.

Other sources include industrial processes, non-transportation fuel combustion, and natural

sources such as wildfires. Pe ak concentrations occur in colder winter months.

Potential health impacts – Reduces oxygen delivery to the body’s organs and tissues. The health

threat is most serious for those who suff er from cardiovascular disease.

Unit of measurement – Parts per million (ppm).

Averaging interval – Highest eight-hour period within a 24-hour period (midnight to midnight)

Reduction tips – Keep motor vehicle tuned properly and minimize nighttime driving.



# PM-10 & PM-2.5 (PARTICLES) :

Description – The term “particulate matter” (PM) includes both solid particles and liquid droplets

found in air. Many manmade and natural sources emit PM directly or emit other pollutants that

react in the atmosphere to form PM. Particles le ss than 10 micrometers in diameter tend to pose

the greatest health concern because they can be inhaled into and accumulate in the respiratory

system. Particles less than 2.5 micrometers in diameter are referred to as “fine” particles and are

responsible for many visibility degradations such as the “Valley Brown Cloud” (see

http://www.phoenixvis.net/ ). Particles with diameters between 2.5 and 10 micrometers are referred

to as “coarse”.

Sources – Fine = All types of combustion (motor vehicles, power plants, wood burning, etc.) and

some industrial processes. Coarse = crushing or grinding operations and dust from paved or

unpaved roads.

Potential health impacts – PM can increase susceptibility to respiratory infections and can

aggravate existing respiratory diseases, such as asthma and chronic bronchitis.

Units of measurement – Micrograms per cubic meter (ug/m3)

Averaging interval – 24 hours (midnight to midnight).

Reduction tips – Stabilize loose soils, slow down on dirt ro ads, carpool, and use public transit.

{ Updated 09/24/2007 

### }

# ADEQ AIR POLLUTION HEALTH WATCH

ISSUANCE NOTICE

Issuance Date and Time: Thursday, March 13, 2008 10:00 a.m.

Valid for Date(s): Friday, March 14, 2008

Pollutant: COARSE PARTICLES (PM-10)

Message: Blowing and suspended dust due to strong

and gusty winds may cause concentrations of

coarse particles to approach unhealthy levels

on Friday.

Detailed air quality forecast information is available on:

• The internet at www.azdeq.gov

• A telephone recording at 602-771-2367

Duty Forecaster: Christopher Reith 520-770-3172

Joe Paul 602-771-2363

Bryan Paris 602/771-7665

CKR 12/06/2007

# MARICOPA COUNTY

DUST CONTROL ACTION FORECAST

ISSUED THURSDAY, MARCH 13, 2008

Three-day weather outlook:

tttttttttttttttttttt

R I S K F A C T O R S

The broad low-amplitude ridge aloft curren tly over the local forecast area will give way to a strengthening and then amplifying

mid-latitude storm track on Friday and thru the weekend. A strong westerly wind event looks likely on Friday and areas of

blowing dust are possible by early afternoon; a MODERATE risk has been posted. A breezy to marginally windy day is

expected on Saturd ay ahead of a strong tr ough and cold front; showers and thunderstorm s are possible on Sunday with the frontal

trough passage. and



## WINDS STAGNATION RISK LEVEL

Day #1: Fri 03/14/2008



## + = Westerly 20-30 mph

with gusts near 40

mph. Little if any stagnation

expected.



## MODERATE

Day #2: Sat 03/15/2008 + = South to southwesterly

15-25 mph. Little if any stagnation

expected.



## LOW

Day #3: Sun 03/16/2008 + = Southwest to westerly

10-20 mph except

strong and gusty near

thunderstorms. Little if any stagnation

expected.



## MODERATE

The Maricopa County Dust Control Ac tion Forecast is issued to assist in the planning of work activities to

help reduce dust pollution. To revi ew the complete air quality forecas t for the Phoenix metropolitan area

and the health effects of air pollution, please see ADEQ's Air Quality Forecast at

http://www.azdeq.gov/environ /air/ozone/ensemble.pdf

, or call 602-771-2367 for recorded forecast

information.03/14/2008 - ADDITIONAL GRAPHSWest 43rd - PM 10 vs. Wind Speed0200400600800100012001400 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:003/14/2008

PM Concentration ( μ g/m^3)051015202530354045 Wind Speed (mph)PM10Max WindDurango - PM 10 vs. Wind Speed02004006008001000120014001600 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:003/14/2008

PM Concentration ( μ g/m^3)051015202530354045 Wind Speed (mph)PM10Max WindSouth Phoenix - PM 10 vs. Wind Speed02004006008001000120014001600 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:003/14/2008

PM Concentration ( μ g/m^3)051015202530354045 Wind Speed (mph)PM10Max WindGreenwood - PM 10 vs. Wind Speed0200400600800100012001400 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:003/14/2008

PM Concentration ( μ g/m^3)051015202530354045 Wind Speed (mph)PM10Max WindPhoenix Area PM10and Meteorological MonitorsSource: US EPA, ADEQ, & Google EarthSalt River Area PM10and Meteorological MonitorsSource: US EPA, ADEQ, & Google Earth

## 26 

# CHAPTER 4: OVERVIEW OF PM 10 

# CONTROL MEASURES

4.1 INTRODUCTION

Chapter 1.2.2 of this SIP ("Regulatory History of the Metropolitan Maricopa PM 10 

# Nonattainment

Area") notes that on July 25, 2002, EPA approved the Maricopa Serious PM 10 

# Nonattainment Area,

and granted Arizona's request, in accordance with CAA § 188(e), to extend the CAA deadline for

attainment of the annual and 24-hour PM 10 

# standards from December 31, 2001, to December 31,

2006 (67 FR 48718).

Because the attainment deadline for this plan revision is also December 31, 2006, and the

measures must be applied to all similar sources throughout the Phoenix Nonattainment Area (see

67 FR 44369, July 2, 2002), the control strategies mu st meet the "Most Stringent Measures" test, as

well as the “Best Available Control Measures/Technology” test. In its July 25, 2002, approval of the

Maricopa County Plan, EPA defined “most stringent measures” (MSMs) as the most stringent

measures included in any state implementation plan, or being implemented in any state, that are

economically and technologically feasible for the nonattainment area in question. “Best Available

Control Measures” (BACM) must be applied in serious nonattainment areas, also taking into

account the economic and technological feasibility of each measure.

This chapter details the proposed BACM and MSM that were evaluated for each significant source

category.

4.2 SOURCE CATEGORIES

The Salt River Study Area 2002 base year emissions inventory is described in Chapter 3.0 and the

TSD’s Chapter 4.0. The 2002 emissions source category contributions to ambient PM 10 

# are

depicted in Table 4.2.1. The average concentrations are derived from the modeled concentrations

outlined in the TSD, Chapter 6.

Assumptions used to calculate trackout emissions appear in Appendix K “Methodology for

Weighting Trackout Emissions” and Appendix P “Mapping Weighted Trackout Emissions into

Predicted Concentrations” of the October 2004 TSD. Calculation methodology for street sweeping

emissions reductions appears in Appendix L “Street Sweeping Reductions” of the October 2004

TSD.

Table 4.2.1 2002 Salt River Study Area Source Category Contributions to Ambient PM 10 

## Concentrations

Average Low Wind

Day Contribution Average High Wind

Day Contribution Highest

Contribution(μg/m 3 

## ) Source Category Percentage

Contribution Percentage

Contribution Low Wind

Day High Wind

Day

Industrial Sources 25.9% 8.3% 60.2 31.8

Point Emissions 2.7% 1.1% 5.3 3.0

Area Emissions 23.2% 7.2% 54.9 28.8

Construction 5.8% 0.9% 6.0 4.4

Area Sources 4.2% 0.7% 8.0 3.1

Unpaved Parking Lots 1.7% 0.2% 0.8 1.4

Unpaved Shoulders 2.5% 0.4% 7.2 1.7

## 27 Table 4.2.1 2002 Salt River Study Area Source Category Contributions to Ambient PM 10 

## Concentrations

Average Low Wind

Day Contribution Average High Wind

Day Contribution Highest

Contribution(μg/m 3 

## ) Source Category Percentage

Contribution Percentage

Contribution Low Wind

Day High Wind

Day

Roads & Trackout 63.7% 13.5% 73.6 42.7

Freeway 0.4% 0.2% 0.7 0.4

Primary Roads 43.6% 9.3% 44.8 33.3

Secondary Roads 7.5% 1.5% 6.9 1.5

Trackout 12.1% 2.5% 21.2 7.5

Agricultural Tillage 0.4% NA 0.2 NA

Windblown Dust NA 76.7% NA 290.1

Agricultural Fields NA 21.3% NA 84.9

Alluvial Channels NA 14.9% NA 79.5

Construction NA 3.5% NA 14.0

Industrial NA 7.3% NA 33.6

Disturbed Areas NA 5.2% NA 25.9

Stockpiles NA 3.6% NA 12.6

Vacant Lots NA 20.9% NA 39.6

Note: Bold concentrations exceed the 5 μg/m 3 

## threshold for significant sources.



# In Table 4.2.2, the modeled contributions for each of the source categories are given for the 2006

attainment case. These percentages are similar to the 2002 case, but with several significant

differences. For example, the windblown contribution decreases from 77% to 59% from 2002 to

2006.

Table 4.2.2 Salt River Study Area Source Category Contributions to Ambient PM 10 

## Concentrations for the 2006 Attainment Case

Average Low Wind Day

Contribution Average High Wind Day

Contribution Source Category

Percentage Contribution Percentage Contribution

Industrial Sources 29.7% 12.1%

Point Source Emissions 

## 4.4% 3.1%

Area Emissions 

## 25.2% 8.9%

Construction 5.2% 1.8 %

Area Sources 7.1% 2.1%

Unpaved Parking Lots 

## 0.5% 0.6%

Unpaved Shoulders 

## 6.6% 1.5%

Roads & Trackout 58.0% 24.7%

Freeway 

## 0.9% 0.4%

Primary Roads 

## 48.3% 21.6%

Secondary Roads 

## 6.8% 1.9%

Trackout 

## 2.0% 0.7%

Agricultural Tillage 0.1% NA

Windblown Dust NA 59.4%

Agricultural Fields 

## NA 8.9%

Alluvial Channels 

## NA 15.4%

Construction 

## NA 4.2%

Industrial 

## NA 6.7%

Disturbed Areas 

## NA 10.1%

Stockpiles 

## NA 5.9%

Vacant Lots 

## NA 8.4%