### Printed on rec y

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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 April 30, 2008

Background

The Arizona Department of Environmental Quality (ADEQ)

issues Dust Control Action Forecasts as part of the Natural

Events Action Plan for the Phoe nix area. On Tuesday, April

29, 2008, in response to a tightening pressure gradient

associated with the tail end of a trough of low pressure and

cold frontal passage through Arizona, ADEQ air quality

forecasters issued the Maricopa County Dust Control Action

Forecast calling for a moderate risk of wind-blown dust and

thus a moderate risk for unhealthy PM 10 

## levels in the Phoenix

area for Wednesday, April 30 th 

## . The Dust Control Action

Forecast called for southwesterly winds of 15 to 25 mph with

stronger gusts possible during the afternoon. In anticipation of

the high winds and blowing dust, a PM 10 

## Health Watch was

issued for April 30 th 

## (See Attachments). These

forecasts/advisories satisfy the requirement in 40 CFR

51.930(a)(1).

This regional high-wind event created the potential for a

wind-blown dust event with a moderate risk of exceeding the

PM 10 

## National Ambient Air Qua lity Standards (NAAQS) in

Maricopa County. Strong winds did occur and were observed

throughout portions of Maricopa County and much of the

Phoenix Metro area on April 30 th 

## , 2008. Beginning in the

morning and continuing until the early evening hours of April

30 th 

## , strong southwesterly winds generated blowing dust

which moved into portions of the Phoenix Metro area. All appropriate State Implementation Plan (SIP) control measures

were in place during the even t, demonstrating per 40 CFR

50.1(j), that the event “is not reasonably controllable or

preventable.” A discussion of commonly employed 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”).

The initialization of a 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 (N WS) monitors (see Fig. 1).

Strong winds gusting to 30 mph at the NWS Phoenix Sky

Harbor station and as high as 41 mph at the NWS Deer Valley

station were reported between 9:00 a.m. and 6:00 p.m., while

many other Valley monitoring lo cations measured wind gusts

over 20 mph. 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 concen trations 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* 172 1065 1100 RJ

Durango Complex (MC/TEOM) 04-013-9812* 69 220 1100 None

Greenwood (MC/TEOM) 04-013-3010* 63 121 1100 None

Higley (MC/TEOM) 04-013-4006* 63 200 0600 None

West Phoenix (MC/TEOM) 04-013-0019* 55 96 1100 None

Central Phoenix (MC/TEOM) 04-013-3002* 51 78 1200 None

JLG Supersite (ADEQ/TEOM) 04-013-9997* 46 91 1100 None

Coyote Lakes (MC/TEOM) 04-013-4014* 53 165 0600 None

South Phoenix (MC/TEOM) 04-013-4003* 88 218 1600 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) PM Spd Max Dir HrT(F)VRDustSpdGustDir HrT(F)VRDustSpdGustDir Hr11 78362 13 NW1 83 10 0 0 N 1 76 10 11 11 SW136.62 77301 9 E 2 76 10 0 0 N 2 74 10 8 8 S 230.53 75322 6 SE 3 76 10 6 6 SE 3 72 10 7 7 S 332.84763549S470101010E4681077E4355 72512 13 NE 5 70 10 8 8 E 5 68 10 6 6 E 551.46 681123 7 NE 6 69 10 11 11 SE 6 68 10 9 9 Ewithw/o61127 681093 7 NE 7 70 10 8 8 E 7 70 10 7 7 EMonitor:Event Event71098 741193 8 N 8 74 10 6 6 E 8 73 10 9 9 SE1-W43RD1726681209 78753 7 N 9 79 10 0 0 N 9 77 10 9 9 SW975.310 83855 20 SW10 82 10 8 8 SW10 79 10 11 21 SW108511874041323SW1186101623SW1182101326SW> NAAQS< NAAQS11404128910651633W1288101830W1284102134SW1210651 9035915 28W1 89 10 20 26W1 86 10 23 31 SW13602 9222213 27 SW2 91 10 18 29W2 87 10 15 41 SW22233 9320813 30 SW3 91 10 14 20 SW3 88 10 18 30W32084 9336515 27 SW4 92 10 17 26W4 89 10 18 26W43665922361528SW590102030W588102329W5236wnd@3m agl/Dir correctedtotrue north6892121325W688101723W685101525SW6212HIGHLIGHTINGCol.Parameter7 8513312 23W7 86 10 17 17W7 83 10 15 29 SW7134Max Wind T(F)Temp.(Deg. F.)8 81776 12W8 83 10 10 10W8 80 10 7 7 SW877.4> 15 mph RHRel Humidity%97962619W9821099W9771033S962.5>25mphRnRain(Inches/hr)10 80469 21 SW10 77 10 6 6 S 10 77 10 11 11 SW1046.8HR - Time (End) SpdAvgSpeed mph11 77287 14 SW11 77 10 6 6 S 11 75 10 8 8 SW1128.5A.M. MaxMax Speed mph12743039SW12741033S12721088SW1230.6P.M.DirWind Dir.(from)4/30-4:00AM4/30-10:00AM4/30-11:00AM4/30-12:00PM4/30-6:00PMHr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir1 76305 10W1 80492 11 SW1 77372 7NW2 78355 17 SW2 82362 10 SW2 75341 8 NE37731511SW3783527SW3724027E47434310S47637210E47237410E5704639NE5715727NE5684539EYrSea6 67602 8 NE 6 69722 5 E 6 66534 9E5 8 4/30 - 6:00AM 4/30 - 10:00AM 4/30 - 11:00AM 4/30 - 12:00PM 4/30 - 4:00PM7 70833 9 NE 7 701352 5 E 7 69585 12 E9 98 77892 7 N 8 76822 7 N 8 75654 7 NE11 119 81752 7 N 9 80733 9NW9 82522 9 NE15 1310 85514 18 SW10 83522 12W10 85424 12W19 1911 868311 23 SW11 861157 23W11 856211 27 SW29 2812862191530W1287163926W12861734W44461 8611215 30W1 891179 25W1 877716 32W65 632 896712 29W2 901389 27W2 895714 29W91 823 925112 33W3 91619 27W3 904113 27W121 1074 9310814 29W4 921399 24W4 915315 31W139 125 4/30 - 6:00AM 4/30 - 10:00AM 4/30 - 11:00AM 4/30 - 4:00PM5 926913 31W5 9221810 27W5 917315 35W157 1346 898514 27W6 901148 22W6 895914 27W192 1947 858212 28W7 87948 20W7 857014 27W227 22088162815W88473310W88147920W3133139 77564 10W9 80921 4SW9 78486 11W107751516SW10807429W107853716W11 75385 10W11 78402 7SW11 783810 19W12733238W12754416W127533313W4/30-6:00AM4/30-10:00AM4/30-4:00PMHr T(F) RH Spd Max Dir Hr T(F) RH Spd Max Dir Hr T(F) RH Spd Max Dir Hr T(F) PM Spd Max Dir1 71 16 1 7W1 76 11 4 11 S 1 79 10 2 11 S 1 72354 9S2 68 20 0 3 SE 2 75 11 4 11 S 2 76 12 3 6 S 2 70402 9 SE3 66 20 3 6 NE 3 74 12 5 12 S 3 73 14 4 8 E 3 64404 9E4 66 18 4 9 SE 4 71 14 5 13 S 4 71 15 5 8 E 4 62376 10 E5 66 21 3 9 SE 5 69 19 3 9 SE 5 68 17 6 10 SE 5 61395 9E4/30 - 6:00AM 4/30 - 10:00AM4/30 - 4:00PM6 63 24 2 6 E 6 66 21 3 11 E 6 67 19 4 9 SE 6 59755 10 SE7 65 25 2 8 E 7 69 23 5 13 S 7 68 23 6 11 SE 7 631995 12 SE8 71 26 2 8 SE8 72 23 7 15 S 8 72 24 7 15 S 8 74588 17 S9 76 26 5 10 S 9 76 21 6 14 S9 76 21 7 15 S 9 7710111 21 S10 84 21 2 11 SW10 80 12 9 19 SW10 80 15 6 16 SW10 816510 24 SW11 88 17 4 22 SW11 83 8 12 27 SW11 84 11 7 21 SW11 846611 26 SW1289121227W128591123SW128781326W128761922W1 90 11 13 30W1 87 8 11 27W1 87 8 14 30W1 884711 27 SW2 92 11 12 26W2 88 8 11 26W2 88 8 13 26W2 904910 27W3 93 13 13 26W3 90 10 11 27 SW3 90 10 11 26W3 92348 23W4/30 - 6:00AM 4/30 - 10:00AM4/30 - 4:00PM4 93 13 11 25W4 91 9 13 29 SW4 91 10 14 30W4 92469 23 SW5 92 12 13 29W5 90 6 15 28 SW5 90 9 13 27W5 917013 28 SW6 90 9 12 27W6 88 5 13 26 SW6 89 6 13 28W6 895412 26W7 85 10 11 23W7 86 6 12 29 SW7 86 6 12 23W7 86539 25W8 81 11 8 17W8 84 7 7 17W8 83 8 8 15W8 82446 15W9 77 12 2 7 NW9 80 8 5 11 SW9 80 9 5 11W9 78695 13 S10 74 14 2 6W10 77 13 9 22 SW10 79 12 4 14 SW10 761119 23 S11 73 18 3 12 SW11 75 16 12 26 S 11 77 15 11 23 S 11 746610 20 SW127221410S127219919S127319820SW1272471120SWPrepared by S. Kendall, A. Juniel, B. Busby and B. Paris/ ADEQ 3/19/09

MC - SOUTH SCOTTSDAL16478 (111.88Wx33.30N)MC - WEST CHANDLER

MC - WEST CHANDLER16398 (111.92Wx33.48N)MC - SOUTH SCOTTSDAL16380 (111.87Wx33.41N)MC - MESA16659 (112.14Wx33.41N)MC - WEST FORTY THIR

MC - WEST FORTY THIR MC - DURANGO COMPLEX16375 (112.12Wx33.43N)MC - DURANGO COMPLEXNWS-Deer Valley AirportFigure 1.Key Data forEvent of April30, 2008KEYPM10 &WIND PLOTWIND &PM10DATAECAHISTDISTWx IMAGERYPHX VIS.CAMERASSUMMARY OF EVENTBeginning at 11:00 am, DeerValley Airport experiencedgusts from the southwest up to41 mph. By noon, widespreaddust aloft was observed. Thevisibility at Goodyear was 7statute miles and winds valleywide were from the southwestbetween 12 to 28 mph withgusts between 18 to 41 mph.

GOES-West Satellit eSee http://ag.arizona.edu/azmet/MC - CENTRAL PHOENIX

MC - CENTRAL PHOENIX MC - MESA16505 (111.72Wx33.31N)AZMET Monitoring LocationsMinColumn Index1-WEST 43RD AVESea - Data for Springseason only(5-Yrs)Yr - All Data(5-Yrs)24-Hr. Avg PM1010%2.5%MC - HIGLEY

MC - HIGLEY50%95%97.5%0.5% WHITE TANK MTN (looking west)

SOUTH MOUNTAIN (looking south)

SUPERSTITION MTN (looking east)Pink=Event Contrib.Conclusion: Asshown above,the PM10concentration wouldhave been below theNAAQS "BUT FOR"the eventcontribution (hourshighlighted in pink).16329 (112.05Wx33.46N)5%Freq.Historical DistributionMONITORS:5-Yr. Dist. of Values (μg/m3)

NWS-Phoenix Sky HarborNWS-Phoenix Sky Harbor NWS-Deer Valley Airport16377 (112.08Wx33.40N)MC - SOUTH PHOENIX

MC - SOUTH PHOENIX90%75%Event Contrib. AnalysisHourly PM10Conc. (μg/m3)1-W43RDCum. Mon 12-Mon 23-Mon 3MONITORS:25%Max99.5%99.0%Conclusion: Flagged Value is exceptional1.0%Value172in nature (ie greater than 95% of all data) (looking northeast)

ESTRELLA MTN (looking south)

CAMELBACK MTNFlagged4/30 - 12:00PM4/30 - 11:00AM 4/30 - 12:00PM4/30-11:00AM4/30-12:00PM4/30 - 11:00AM 4/30 - 12:00PMWest 43rd - PM 10 vs. Wind Speed020040060080010001200 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 23:004/30/2008

PM Concentration ( μ g/m^3)05101520253035 Wind Speed (mph)PM10Max Wind

## Assessment of April 30, 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 a filter sampling date (1-in-6 run

day), data from both the continuous analyzers and filter based

monitors were examined. The air quality monitoring data

were reviewed by the agency responsible for operation of the

monitor. All hourly PM 10 

## readings from the West 43 rd 

## Ave.

monitoring site were valid for April 30, 2008. Audits of the

analyzers revealed operations were within acceptable

tolerance. No local sources we re reported as significantly

contributing to the air quality episode. Exceedances of the

NAAQS were recorded by the continuous monitor located 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

as to what meteorological condi tions were in place on April

30 th 

## . Strong westerly to southwesterly winds occurred in the

Phoenix area due to a low pressure system approaching from

the west. The plot of hourly PM 10 

## concentration and max

wind data in the upper right corner of Figure 1 confirms the

nearly identical timing of the elevated PM 10 

## concentrations

and the strong wind gusts recorded by the West 43 rd 

## Ave.

monitor. The high wind event was a regional phenomenon

that affected the entire Phoe nix 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 attribut ed 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 allocations can be assumed for this April 30, 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 MC and NWS 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 9:00

a.m., when several stations re ported gusty winds over 20 mph.

This 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 a

time when winds, including those reported at Sky Harbor and

Deer Valley airports, decr eased 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 April 30, 2008.

Visual evidence of reduced visibility can be seen in the

images located in the lower right portion of Figure 1. These

images, along with the graph of West 43 rd 

## wind gusts and

PM 10 

## concentrations, provide proof that the elevated PM 10



## concentrations in Phoenix were coincident with strong gusty

winds and 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 in 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 April 30, 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

NEW!!! CLICK HERE FOR UPDATED 2008 OZONE SEASON STATS NEW!!!



# AIR QUALITY FORECAST FO R WEDNESDAY, APRIL 30, 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

MON 04/28/2008

NONE

Highest AQI Reading/Site

(Preliminary data only) 

# TODAY

TUE 04/29/2008

NONE 

# TOMORROW

WED 04/30/2008

OZONE HEALTH

WATCH

PM-10 HEALTH

WATCH 

# EXTENDED

THU 05/01/2008

NONE



# O3* 90

NORTH PHOENIX 

## 84

MODERATE 

## 97

MODERATE 

## 87

MODERATE



# CO* 13

WEST INDIAN SCHOOL 

## 11

GOOD 

## 8

GOOD 

## 9

GOOD



# PM-10* 59

BUCKEYE 

## 68

MODERATE 

## 90

MODERATE 

## 57

MODERATE



# PM-2.5* 65

DURANGO 

## 58

MODERATE 

## 54

MODERATE 

## 51

MODERATE

## Health message for Tuesday, Apr 29: Unusually sensitive people should consider

reducing prolonged or heavy exertion outdoors.

Health message for Wednesday, Apr 30: Unusually sensitive people should

consider reducing prolonged or heavy exertion outdoors.

Synopsis and Discussion

*An Ozone Health Watch AND a PM10 Health has been issued for Wednesday, April 30, 2008*



## Ozone levels continue to hold in the mid to upper “Mode rate” range with little relief. It’s only going to get

worse before it gets better as a trough of low pressure moves through the western U.S. the next couple of

days. The tail end of the disturbance will impact Arizona Wednesday with winds increasing to 30 mph at

times across the deserts, even stronger in higher eleva tions of Arizona. Yuma is already indicating that

another transport situation is underway with Ozone in the upper “Moderate” range on Tuesday. That

means that today and likely tomorro w should see some high levels across the Phoenix forecast. An

increase in winds also means we could see areas of blowing dust across the dry deserts (now 65

consecutive days without measurable rain in Phoenix). As a result of this latest weather system and its

potential impact on the Valley’s air quality, we are issuing both an Ozone and PM10 Health Watch for

Wednesday . The situation will be re-evaluated tomorrow, but conditions should improve Thursday and

Friday as the system exits the region. Check back then for the latest. Have a good day! –J.Paul

MONITORING SITE MAPS: STATIC MAP

- http://www.azdeq.gov/environ/air/monitoring/images/map.jpg

INTERACTIVE MAPS - http://aqwww.maricopa.gov/AirM onitoring/SitePollutionMap.aspx

http://www.airnow.gov /



# POLLUTION MONITOR READINGS FOR MONDAY, APRIL 28, 2008



# O3 (OZONE)

For facts on new 8-hr ozone standard go to: http://www.epa.gov/air/ozonepo llution/pdfs/2008_03_aqi_changes.pdf

For maps go to: http://www.airnow.gov/index.cfm?action=airnow.currentconditions

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

Alamo Lake (La Paz County) NOT AVBL NOT AVBL NOT AVBL



### Apache Junction (Pinal County) 64 64

Blue Point 50 42

Buckeye 65 67

Casa Grande (Pinal County) 67 74

Cave Creek 71 87

Central Phoenix 66 71

Combs School (Pinal County) 62 58

Dysart 67 74

Falcon Field 61 54

Fountain Hills 64 64

Glendale 70 84

Humboldt Mountain 66 71

Maricopa (Pinal County) 65 67

North Phoenix 72 90

Phoenix Supersite NOT AVBL NOT AVBL NOT AVBL



### Pinal Air Park (Pinal County) 65 67

Pinnacle Peak 67 74

Queen Valley (Pinal County) 66 71

Rio Verde 66 71

South Phoenix 68 77

South Scottsdale 64 64

Tempe 67 74

Tonto Nat’l Mon. (Gila County) 66 71

West Chandler 65 67

West Phoenix 71 87

Yuma (Yuma County) 70 84

# CO (CARBON MONOXIDE)

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

Central Phoenix 0.8 9

Greenwood 0.9 10

Phoenix Supersite NOT AVBL NOT AVBL NOT AVBL



### West Indian School 1.1 13

West Phoenix 1.0 11



# PM-10 (PARTICLES)

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

Buckeye 72.3 59

Central Phoenix 39.9 36

Combs School 

### (Pinal County) 87.8 67

Coyote Lakes 46.0 42

Durango 59.1 53

Greenwood 58.2 53

Higley 62.0 54

Maricopa (Pinal County) 73.6 60

Phoenix Supersite 38.3 35

South Phoenix 59.2 53

West Forty Third 63.0 55

West Phoenix 48.5 44



# 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 21.3 65

Dysart 6.5 21

Estrella Mountain Park 10.5 34

Phoenix Supersite 14.6 47

Vehicle Emissions Lab 8.0 26

West Phoenix 12.6 41



# 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 08/14/2007 

### }

# ADEQ AIR POLLUTION HEALTH WATCH

ISSUANCE NOTICE

Issuance Date and Time: Tuesday, April 29, 2008 11:30 a.m.

Valid for Date(s): Wednesday, April 30, 2007

Pollutant: Course Particulates (PM-10)

Message: Elevated particulate levels combined with

breezy to windy conditions Wednesday may

lead to concentrations approaching the

health standard.

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 602-771-2360

Joe Paul 602-771-2363

CKR 01/18/2005

# MARICOPA COUNTY

DUST CONTROL ACTION FORECAST

ISSUED TUESDAY, APRIL 29, 2008

Three-day weather outlook:

A trough of low pressure will move through the western U.S. the next several days with the tail end of the disturbance impactin g

Arizona Wednesday afternoon. Winds will in crease out of southwest and west to around 30 mph at times across the deserts,

lasting into early hours of Thursday befo re decreasing. Cooler air will filter in behind the system which means afternoon dese rt

temperatures will only be in the upper 80s on Thursday. Winds will be much lighter Thursday afternoon through Friday. The

risk of exceeding the 24-hr PM10 health standard in Phoenix will be “Moderate” on Wednesday, dropping back to “Low” by

Thursday.



## R I S K F A C T O R S

WINDS STAGNATION RISK LEVEL

Day #1: Wed 04/30/2008 

## + = Southwest winds 15 to

25 mph with stronger

gusts possible at times

are expected during

the afternoon hours. Little to no stagnation

is expected.



## MODERATE

Day #2: Thu 05/01/2008 

## + = Slightly stagnant

conditions are

expected early with

improvement by the

afternoon. West winds 10 to 15

mph are expected

during the afternoon

hours. 

## LOW

Day #3: Fri 05/02/2008



## + = Somewhat stagnant

conditions are

expected early with

improvement by the

afternoon. West winds 5 to 10

mph are likely much of

the day.



## LOW

To review the complete air quality forecast for the Phoenix metropolitan area visit www.azdeq.gov or call

602-771-2367 for recorded forecast information.04/30/2008 - ADDITIONAL GRAPHSWest 43rd - PM 10 vs. Wind Speed020040060080010001200 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 23:004/30/2008

PM Concentration ( μ g/m^3)05101520253035 Wind Speed (mph)PM10Max WindSouth Phoenix - PM 10 vs. Wind Speed020040060080010001200 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 23:004/30/2008

PM Concentration ( μ g/m^3)05101520253035 Wind Speed (mph)PM10Max WindDurango - PM 10 vs. Wind Speed020040060080010001200 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 23:004/30/2008

PM Concentration ( μ g/m^3)05101520253035 Wind Speed (mph)PM10Max WindGreenwood - PM 10 vs. Wind Speed020040060080010001200 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 23:004/30/2008

PM Concentration ( μ g/m^3)05101520253035 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%