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Assessment of Qualification for Treatment under the Arizona Natural and Exceptional 

Events Policy for the High Particulate (PM10) Concentration Events in the 

Phoenix and Yuma Areas on June 4, 2008 

Background

The Arizona Department of Environmental Quality (ADEQ) 

issues Dust Control Action Forecasts for the Yuma and 

Phoenix areas as part of their Natural Events Action Plans. 

On Tuesday, June 3, 2008, in response to a deepening upper 

level trough of low pressure and an approaching dry surface 

cold front, ADEQ air quality forecasters issued the Maricopa 

County Dust Control Action Forecast calling for a moderate 

risk of wind-blown dust for Wednesday, June 4th, in Maricopa 

County. Because the tightening pressure gradient and dry 

cold front was expected to impact the Yuma area as well, 

ADEQ air quality forecasters called for a high risk of windblown dust in their Yuma and Vicinity Dust Control Action 

Forecast for Wednesday, June 4th. This potential wind event 

equated to a significant risk of exceeding the PM10 National 

Ambient Air Quality Standards (NAAQS) in both Yuma and 

Maricopa Counties. On the morning of June 4th, weather 

models predicted local wind gusts to be even stronger than the 

previous day’s model runs had anticipated, prompting ADEQ 

forecasters to issue a same day PM10 Health Watch for 

Maricopa County stating that “Blowing and suspended dust, 

contributed to by strong and gusty gradient winds, may cause 

concentrations of coarse particles to approach unhealthy 

levels this afternoon and evening”. The forecasts/advisories 

satisfy the requirement in 40 CFR 51.930(a)(1). 

While the initial forecast for June 4th for both Maricopa 

County and Yuma called for sustained winds of 15-25 mph 

with the possibility for gusts over 30 mph, subsequent 

forecasts the morning of June 4th called for even stronger 

winds which prompted the Health Watch. Beginning in the 

early afternoon and continuing throughout the evening hours, 

strong southwesterly winds in Phoenix and strong westerly 

winds in Yuma generated areas of blowing dust. A detailed 

review of Best Available Control Measures (BACM) 

inspection reports was conducted for areas in the vicinity of 

the exceeding monitors (see attachment). Aside from the 

minor exceptions noted near the West 43rd and Coyote Lakes 

monitors, 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 employed BACM for dust in Maricopa and Yuma 

counties can be found in “High Wind Exceptional Events and 

Control Measures for PM10 Areas” (see “References”). 

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

6:00-6:30 p.m. Phoenix visible camera images, as well as the 

Arizona Meteorological Network (AzMET), Maricopa 

County (MC), ADEQ, and National Weather Service (NWS) 

monitors (see Fig. 1). This significant wind event brought 

elevated ambient concentrations of PM10 to the Phoenix and 

Yuma areas that exceeded the NAAQS at the Yuma 

Courthouse, Buckeye, West 43rd Ave. and Coyote Lakes 

monitors. 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 PM10 monitor readings for the 

monitors examined in this report. 

 

Monitor (Operator/Type) AQS ID 24-hr Avg PM10 1-hr Max PM10 Max Time Flag** 

YUMA AREA 

 Yuma Courthouse (ADEQ/TEOM) 04-027-0004* 386 2341 2000 RJ 

BUCKEYE AREA 

 Buckeye (MC/TEOM) 04-013-4011* 204 772 2300 RJ 

PHOENIX METRO AREA 

 West 43rd Ave (MC/TEOM) 04-013-4009* 194 645 1400 RJ

 Coyote Lakes (MC/TEOM) 04-013-4014* 187 656 2300 RJ 

* EPA Air Quality System Identification Number 

** 24-hr PM10 concentration influenced by natural or exceptional event to be flagged. 

Type Abbreviations: BAM – Beta-Attenuation Mass Monitor (Continuous monitor) 

 TEOM – Tapered Element Oscillating Microbalance Monitor (Continuous monitor). 

The preliminary findings from this analysis were presented at 

stakeholders meetings on November 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). 
Hr T(F)

V

R Dust Spd Gust Dir Hr T(F) RH PM Spd Max Dir Hr 123

Hr 1

1 75 10 0 0 N/A 1 72 29 44 1 4N 1 44.7 52 496 1 48.7

2 80 10 8 8 S

W 2 70 32 36 0 5N 2 36.3 34 373 2 44.7

3 75 10 6 6

W 3 70 32 37 0 5 NE 3 37.2 35 402 3 44.3 4 75 10 5 5 S 4 66 40 42 2 5 NE 4 42.7 71 95.7 4 105

5 73 10 0 0 N/A 5 65 41 45 3 6 NE 5 45.4 65 80.3 5 18.46 69 10 0 0 N/A 6 66 38 67 1 6 NE with w/o 6 67.3 142 143 with w/o 6 37.57 72 10 0 0 N/A 7 70 39 116 1 4 NE Monitor: Event Event 7 117 199 190 Monitor: Event Event 7 33.2

8 75 10 -DZ 3 3 *VR 8 77 24 63 1 6 SE 1-BUCKE 204 53 8 63.4 90 74 4-YUMA C 386 55 8 46.4

9 82 10 0 0 N/A 9 83 18 44 6 19 S 2-W43RD 194 78 9 44.2 85 24.5 9 42.3

10 84 10 -DZ 11 16 S 10 86 15 19 10 20 S

W 3-COYOT 186 130 10 19 67 21.6 10 69.2

11 88 10 20 25 SW 11 89 17 27 10 18 SW > NAAQS < NAAQS 11 27.8 40 28 > NAAQS < NAAQS 11 42.112 89 10 17 26 S 12 91 18 34 14 26 SW 12 34.2 64 35.7 12 50.6

1 90 10 21 28 S

W 1 92 17 38 15 28 S

W 1 38.2 165 37.4 1 75.9

2 92 10 23 32 S

W 2 93 19 48 17 29 S

W 2 48.8 307 37.6 2 119

3 93 10 24 33 S

W 3 94 19 66 19 33

W 3 66.1 645 43 3 183

4 93 10 26 36 S

W 4 94 19 131 21 34

W 4 131 520 84.3 4 570 5 93 10 29 36 SW 5 93 19 210 24 36W 5 210 382 83.5 5 301 wnd @3m agl / Dir corrected to true north

6 92 10 28 36 SW 6 92 20 285 23 40 SW 6 285 569 96.7 6 547 HIGHLIGHTING Col. Parameter7 90 4 BLDU 25 36 S

W 7 89 22 411 21 36 S

W 7 411 266 229 7 570 Max Wind T(F) Temp. (Deg. F.)

8 86 6 DU 24 33 S

W 8 87 24 570 20 35 S

W 8 570 161 313 8 2163 > 15 mph RH Rel Humidity % 9 84 10 23 28 SW 9 84 25 515 15 29 SW 9 515 95 254 9 2341 >25 mph Rn Rain (Inches/hr)

10 82 10 21 21 S

W 10 82 27 510 14 27 S

W 10 511 84 272 10 965 HR - Time (End) Spd Avg Speed mph

11 80 9 24 24 S

W 11 80 29 759 17 28 S

W 11 760 241 417 11 523 A.M. Max Max Speed mph

12 78 6 HZ 23 23 SW 12 77 33 771 13 22 SW 12 772 283 656 12 343 P.M. Dir Wind Dir. (from)

6/04 - 5:00AM 6/04 - 1:00PM 

Hr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir

1 71 495 2 5 NE 1 80 51 3 7S

2 69 373 2 5 N 2 77 33 1 8N

W

3 68 401 1 5 N 3 76 34 0 8 NW4 66 95 1 4 N 4 72 71 3 8 E5 65 80 1 4 NE 5 71 65 4 7 NE Yr Sea Yr Sea Yr Sea Yr Sea

6 65 143 2 5 N 6 71 141 1 6E 5 14 5 16 7 10 8 13 6/04 - 2:00PM 6/04 - 6:30PM 7 72 189 2 5 NE 7 73 199 1 7 NE 7 15 9 18 7 14 12 168 83 74 1 4 SE 8 78 89 5 9E 9 15 11 18 9 17 14 169 87 24 2 6 S 9 82 85 3 9E 13 17 15 20 10 19 16 20

10 89 21 5 16 S

W 10 87 67 0 9

W 16 21 19 24 14 19 19 20

11 90 28 8 20 S

W 11 91 39 4 16 S

W 22 25 29 31 19 21 23 25

12 91 35 9 21 SW 12 95 64 7 19

W 33 34 44 40 30 31 31 34

1 92 37 10 26 S

W 1 96 165 12 24 S

W 48 49 65 61 44 46 42 43

2 94 37 11 26 S

W 2 95 306 14 27 S

W 67 68 91 82 58 62 57 62

3 94 43 12 27 S

W 3 96 644 17 30 S

W 83 86 121 102 77 77 77 85

4 96 84 14 32 S

W 4 96 520 17 36 S

W 98 101 139 127 91 102 96 102 6/04 - 2:00PM 6/04 - 6:30PM 

5 95 83 15 34 S

W 5 95 381 16 31 S

W 120 115 157 157 109 119 127 132

6 94 96 14 30 S

W 6 94 569 16 35 S

W 159 131 192 251 122 138 186 165

7 92 228 17 37 S

W 7 91 266 17 31 S

W 260 155 227 251 219 206 211 193

8 88 312 10 30 SW 8 88 161 17 30 SW 289 195 313 251 313 273 349 2249 84 254 10 26 S

W 9 86 94 14 27 S

W

10 82 271 11 25 SW 10 84 84 14 30 SW11 81 416 9 22 S

W 11 82 240 17 27 S

W

12 79 656 9 24 SW 12 79 283 16 29 SW

6/04 - 2:00PM 6/04 - 6:30PM 

Hr T(F) PM Spd Max Dir Hr T(F) PM Spd Max Dir Hr T(F) VR Dust Spd Gust Dir Hr T(F) RH Spd Max Dir

1 77 28 2 6 S 1 78 42 2 8 SE 1 77 10 3 3 S 1 75 27 2 8

W

2 75 53 1 5 NE 2 74 41 4 8 E 2 79 10 0 0 N 2 73 29 2 9 N

W

3 74 45 1 7 NE 3 72 36 4 10 E 3 75 10 3 3 S 3 69 37 4 8 S

4 72 46 2 6 E 4 71 39 4 9 E 4 76 10 3 3 N

W 4 66 44 3 7 S

5 71 50 2 6 NE 5 70 41 4 8 E 5 75 10 8 8

W 5 63 48 4 9 S 6/04 - 2:00PM 6/04 - 6:30PM 

6 70 49 4 9 E 6 70 46 4 8 E 6 74 10 5 5 N

W 6 66 38 3 5 S

7 73 55 4 11 E 7 76 52 5 9 E 7 77 10 7 7 N

W 7 69 38 2 6 S

W

8 79 55 5 10 E 8 80 36 6 12 E 8 80 10 13 13

W 8 74 32 5 12

W

9 86 49 3 9 E 9 85 36 5 10 E 9 83 10 7 7

W 9 77 25 6 11

W

10 90 46 2 9 SE 10 90 37 2 9 E 10 86 10 5 5 S

W 10 82 22 8 15

W

11 92 35 3 11 S 11 92 32 5 15 S

W 11 91 10 3 3 *VR 11 85 19 9 16 S

W

12 94 29 4 20

W 12 93 28 5 16 SW 12 95 10 15 22 SW 12 89 18 11 20 SW

1 94 53 11 25

W 1 93 34 9 24

W 1 97 10 10 10 S

W 1 92 17 12 21 S

W

2 94 77 12 27

W 2 94 64 13 28

W 2 100 10 22 28

W 2 94 15 16 28

W

3 95 189 16 32

W 3 94 163 16 34

W 3 100 6 BLDU 22 29

W 3 94 15 18 34

W 6/04 - 2:00PM 6/04 - 6:30PM 

4 96 217 15 31 S

W 4 93 204 17 33

W 4 98 10 17 28

W 4 92 15 20 33

W

5 95 166 15 33

W 5 94 141 18 34

W 5 96 6 HZ 24 37

W 5 91 16 19 32

W

6 94 154 15 33

W 6 92 166 17 37

W 6 93 10 HZ BL 23 30

W 6 88 20 15 26

W

7 91 133 14 28 S

W 7 90 180 17 34 S

W 7 88 3 HZ BL 22 33 N

W 7 85 23 18 29

W

8 87 113 12 26 S

W 8 87 135 16 31 S

W 8 81 10 HZ BL 23 36

W 8 79 29 26 38

W

9 85 79 12 25 S

W 9 85 102 17 32

W 9 77 0.50sHZs 22 39 N

W 9 75 35 25 40

W

10 83 69 12 28 S

W 10 84 76 15 28

W 10 75 10 HZ BL 20 31 N

W 10 73 37 26 40

W

11 81 210 15 28 S

W 11 81 177 15 31 S

W 11 75 5 BLDU 14 20

W 11 72 37 21 29 N

W

12 79 237 12 28 SW 12 79 303 16 33

W 12 75 10 BLDU 11 23

W 12 72 35 15 28

W

ADEQ - YUMA AGRI CEN

ADEQ - YUMA AGRI CEN

128530 (114.71Wx32.71N)

MC - COYOTE LAKES

MC - COYOTE LAKES

MC - WEST FORTY THIR

MC - WEST FORTY THIR

16329 (112.05Wx33.46N)

MC - CENTRAL PHOENIX

MC - CENTRAL PHOENIX

127530 (112.31Wx33.67N)

MC - DURANGO COMPLEX

16375 (112.12Wx33.43N)

MC - DURANGO COMPLE

X

MC - BUCKEYE

MC - BUCKEYE

21525 (112.62Wx33.37N)16659 (112.14Wx33.41N)

GOES-West Satellite

AZMET Monitoring Locations

See http://ag.arizona.edu/azmet/

F

Ke

Eve

NWS-Luke AFB

186

2-W43RD3-COYOTE

MONITORS:

Event Contrib. Analysis

24-Hr. Avg PM10

Conclusion: As shown above, the PM10 concentration would have been below the NAAQS "BUT FOR" the event contribution (hours highlighted in pink).Conclusion: Flagged Value is exceptional

NWS-Yuma MCAS

99.0%

90%

MONITORS:

1-BUCKEYE2-WEST 43RD3-COYOTE LAKES

Hourly PM10 Conc. (μg/m3

)

1-BUCKEYE

99.5%

NWS-Yuma MCAS

in nature (ie greater than 95% of all data)

NWS-Luke AFB

204 194

Mon 1 Mon 2

Flagged

10%

 5%

75%

Pink=Event Contrib.

50%

5-Yr. Dist. of Values (μg/m3

)

Column Index

Flagged

Yr - All Data (5-Yrs)

Mon 1

Pink=Event Contrib.

Conclusion: As shown above, the PM10 

concentration wouldhave been below theNAAQS "BUT FOR" the event contribution (hours highlighted in pink).

MONITORS:MONITORS:

Event Contrib. Analysis

Hourly PM10 Conc. (μg/m3

)

4-YUMA CH

 season only (5-Yrs)

Freq.

 2.5%

4-YUMA CH

24-Hr. Avg PM10

Cum.

25%

Value

Mon 3

95%

97.5%

Cum.

Historical Distribution

5-Yr. Dist. of Values (μg/m3

)

 1.0% 0.5%

Min

Column Index

Max

Yr - All Data (5-Yrs)

Sea - Data for Summer

Historical Distribution

Sea - Data for Summer

 season only (5-Yrs)

WHITE TANK MTN

(looking west)

Conclusion: Flagged Value is exceptional ESTRELLA MTN

(looking south) Value 386

Freq.

Max

99.5%99.0%

90%75%

in nature (ie greater than 95% of all data)

95%

97.5%

SOUTH MOUNTAIN

(looking south)

50%

 1.0% 0.5%

Min

25%10%

 5%

 2.5%

CAMELBACK MTN

(looking northeast)

SUPERSTITION MTN

(looking east)

WIND & 

PM10 

DATA

SUM

At 2:00 pexperiengusts up visibility dust at 3wind gusmph. By began ex25 mph wreduced 
Assessment of June 4, 2008 event (Cont.) 

- 4 - 

Assessment under the Technical Criteria Document (TCD)

1. Properly qualify and validate 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 operation of the monitor. All 

hourly PM10 readings from the Yuma Courthouse, Buckeye, 

West 43rd Ave. and Coyote Lakes monitoring sites were valid 

for June 4th. Audits of the analyzers revealed operations were 

within acceptable tolerance. 

2. Review suspected contributing sources. The NWS, 

AzMET, and MC surface data for Arizona provide a good 

explanation as to what meteorological conditions were in 

place on June 4th. Strong southwesterly winds were occurring 

in the Phoenix area due to a low pressure system approaching 

from the northwest with a cold front passing over Arizona. 

PM10 concentrations were elevated throughout much of the 

Phoenix Metro area as evidenced by the PM10 and wind speed 

plots (see attachments). PM10 concentrations also spiked at 

Yuma Courthouse during the afternoon and evening hours as 

winds increased out of the west and northwest in Yuma. The 

plot of hourly PM10 concentration data in the upper right 

corner of Figure 1 confirm the nearly identical timing of the 

elevated PM10 concentrations recorded at West 43rd Ave., 

Coyote Lakes, Buckeye, and Yuma. Phoenix visibility 

camera images show the reduced visibility associated with 

this high wind event. These images indicate that reduced 

visibilities due to blowing dust were widespread throughout 

the entire Valley. While this visual evidence is not possible 

for the Yuma area, Yuma radar data show the transport of 

blowing dust from southeastern California into southwestern 

Arizona (see attachment for more detail). 

3. Examine all air quality monitoring information. Data from 

all monitors in the network were reviewed. Monitors from 

the affected areas are summarized in the table in the 

Background section of this assessment. 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 95th percentile). Additionally, 

the winds associated with the elevated PM10 concentrations 

may be characterized as ‘unusual’ as described in “Impact of 

Exceptional Events’ ‘Unusual Winds’ on PM10

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 and southern Arizona until approximately noon, 

when several stations began reporting wind gusts of 20 mph 

or greater. As winds continued to increase through the 

afternoon, the onset of elevated PM10 concentrations began at 

the four flagged monitoring sites, each of which continued to 

show higher PM10 values as winds increased throughout the 

day. Apart from a two hour lull in PM10 concentrations at 

West 43rd Ave. around 9:00 p.m., elevated concentrations at 

each flagged monitoring site continued throughout the 

evening. 

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

evidence indicates the elevated PM10 concentrations in the 

Phoenix and Yuma areas can be attributed to soil emissions 

that were transported over portions of Maricopa County and 

Yuma County. No source specific emission allocation is 

possible based on the data available for analysis. Visual 

evidence of reduced visibility during the 6:00 p.m. hour can 

be seen in the images located in the lower right portion of 

Figure 1. These images provide proof that the elevated PM10

concentrations in and round Phoenix were coincident with 

strong, gusty winds and can be attributed to soil emissions. In 

addition, visibility was reduced to 0.5 miles with haze and 

blowing dust reported by trained weather spotters at the Yuma 

MCAS during the afternoon and evening hours of June 4. 

These observations provide further evidence that the elevated 

PM10 concentrations recorded at Yuma Courthouse were the 

result of a wind-blown dust event. 

6. Estimation of Contribution from Source or Event. The 

primary source appears to be wind-blown dust over central 

and southern 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 between the measurements to be 

flagged and the event, thus satisfying 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 exceedances or violations but for the event (i.e., 

the contribution during the event overwhelmed the 24-hour 

averages). 

 

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 concentrations at Yuma Courthouse, Buckeye, West 

43rd Ave., and Coyote Lakes were attributed to a natural 

event. 

Conclusion

Transport of dust from soils by high winds. The region wide 

elevated PM10 event on June 4, 2008, in Yuma and Maricopa 

Counties was the result of transported dust and soils from 

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 NAAQS 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 Environmental 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 (PM10) (May 31, 2000). 

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

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

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

‘Unusual Winds’ on PM10 Concentrations (October 14, 2009). 

Arizona Department of Environmental Quality (ADEQ), High Wind Exceptional Events 

and Control Measures for PM10 Areas (October 14, 2009). 

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

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

(November 21, 2008). 
ADEQ AIR POLLUTION HEALTH WATCH

ISSUANCE NOTICE 

Issuance Date and Time: Wednesday, June 04, 2008 6:15 a.m. 

Valid for Date(s): Wednesday June 04, 2008 

Pollutant: COARSE PARTICLES (PM-10) 

Message: Blowing and suspended dust, contributed to 

by strong and gusty gradient winds, may 

cause concentrations of coarse particles to 

approach unhealthy levels this afternoon and 

evening. 

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 05/01/2007 
MARICOPA COUNTY 

DUST CONTROL ACTION FORECAST

ISSUED TUESDAY, JUNE 02, 2008

Three-day weather outlook:

 

tttttttttttttttttttt 

R I S K F A C T O R S

On Wednesday an upper level trough in the mid-latitude storm track will deepen over the western U.S. including Arizona. 

Increasing afternoon winds are therefore expected on Wednesday when gradients will be the strongest. There will be an 

increased risk for areas of blowing dust after the noon hour lasting into the evening hours. 

 

 WINDS STAGNATION RISK LEVEL

Day #1: Wed 06/04/2008

+ =

 

 

Southwest to westerly 

15-25 mph with gusts

Rather stagnant during 

the morning hours 

with improvement by 

afternoon. 

 

 MODERA

over 30 mph by 

afternoon. TE 

 

Day #2: Thu 06/05/2008 + = 

West to northwesterly 

10-20 mph. 

Rather stagnant during 

the morning hours 

with improvement by 

afternoon. 

 LOW 

 

 

Day #3: Fri 06/06/2008 + = 

Rather stagnant during 

the morning hours 

with improvement by 

afternoon. 

 

 LOW 

Southwesterly 5-15 

mph by afternoon.

 

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

help reduce dust pollution. To review the complete air quality forecast 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. 
 YUMA AND VICINITY 

DUST CONTROL ACTION FORECAST

 ISSUED TUESDAY, JUNE 03, 2008

Three-day weather outlook:

tttttttttttttttttttt 

 

 

On Wednesday an upper level trough in the mid-latitude storm track will deepen over the western U.S. including Arizona. 

Increasing afternoon winds are therefore expected the next few days – but especially on Wednesday – when gradients will be the 

strongest. There will be a HIGH risk for localized (not widespread) blowing dust after the noon hour lasting into the evening 

hours. 

 WINDS WIND-BLOWN DUST RISK 

 

Day #1: Wed 06/04/2008 

 

Westerly 15-25 mph 

with gusts to 30 mph 

by afternoon. 

 HIGH 

 

 

 

 

Day #2: Thu 06/05/2008 

Northwest to northerly 

10-20 mph with a few 

higher gusts, 

decreasing by 

afternoon. 

 

 

 MODERATE 

 

Day #3: Fri 06/06/2008 

No significant winds 

expected. 

 LOW 

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 

less 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 (brown cloud). 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, minimize travel on dirt roads, utilize tarps on haul trucks, limit use of leaf-blowers, 

and on high-wind days reduce outdoor activities. 

 CKR 05/09/2005
06/04/2008 - ADDITIONAL GRAPHS 1

West 43rd - PM 10 vs. Wind Speed

0

100200300400500600700800900

1000

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

23:00

6/4/2008

PM Concentration (μg/m^3)

0510152025303540

Wind Speed (mph)

PM10Max Wind

Coyote Lakes - PM 10 vs. W

0

100200300400500600700800900

1000

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

6/4/2008

PM Concentration (μg/m^3)

PM10Max Wind

Buckeye - PM 10 vs. Wind Speed

0

100200300400500600700800900

1000

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

23:00

6/4/2008

PM Concentration (μg/m^3)

051015202530354045

Wind Speed (mph)

PM10Max Wind

Yuma Courthouse - PM 10 vs. 

0

500

1000150020002500

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

6/4/2008

PM Concentration (μg/m^3)

PM10Max Wind
06/04/2008 - ADDITIONAL GRAPHS 2

Durango - PM 10 vs. Wind Speed

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100150200250300350

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6/4/2008

PM Concentration (μg/m^3)

0510152025303540

Wind Speed (mph)

PM10Max mph

Central Phoenix - PM 10 vs. 

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100150200250300350

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6/4/2008

PM Concentration (μg/m^3)

PM10Max mph

Greenwood - PM 10 vs. Wind Speed

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100150200250300350

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6/4/2008

PM Concentration (μg/m^3)

0510152025303540

Wind Speed (mph)

PM10Max mph

West Phoenix - PM 10 vs. W

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100150200250300350

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6/4/2008

PM Concentration (μg/m^3)

PM10Max mph
Phoenix Area PM10 and Meteorological Monitors 

Source: US EPA, ADEQ, & Google Earth 
Salt River Area PM10 and Meteorological Monitors 

Source: US EPA, ADEQ, & Google Earth 
Yuma Area PM10 and Meteorological Monitors 

Source: US EPA, ADEQ, & Google Earth 
June 4th 2008 Radar and Satellite Data 

Radar data obtained from the National Oceanic and Atmospheric Administration’s 

National Climatic Data Center in conjunction with MODIS satellite photography 

obtained from NASA’s Rapid Response System allows for a visual reassessment of the 

event. These data were downloaded as KMZ files and displayed using Google Earth 

software. The overlay of the products clearly shows that much of the suspended dust 

originated in southeastern California and was transported to the east. It can be seen that 

large sources of dust appear to come from the Imperial Sand Dunes of southern 

California (also known as the Algodones Dunes) and other similar dunes or open desert 

areas to the southwest of the Salton Sea. Another common source of blowing dust 

appears to be an area of open desert to the south / southeast of Yuma. While some of the 

radar images are obscured by noise, the dust sources are still clearly visible. 

Figure 1 - Radar data and MODIS satellite imagery show a major source of blowing dust located to 

the southwest of the Salton Sea. 

 
Figure 2 – Just prior to the time of highest PM10 concentrations in the Yuma area, radar data show 

what are likely high concentrations of blowing dust to the west / northwest of Yuma. These returns 

(shown as white colors) are likely indicative of blowing dust originating from the Imperial Sand 

Dunes. 
The MODIS satellite data are from the Terra satellite with 250 meter resolution and use 

bands 7, 2, and 1 to accentuate vegetation. Lighter tan areas are indicative of open desert 

while darker brown areas indicate areas of higher elevation or differing soil type 

(compared to that of the open desert). The suspected PM sources are outlined in the 

image below. 

Figure 3 - Image courtesy of MODIS Rapid Response Project at NASA/GSFC displayed using 

Google Earth software. 
PM10 Control Measures Reporting Form 

High Wind Exceptional Event Demonstration

Date of Flagged Event ___June 4, 2008____________________________________

PM10 Planning Area __ Maricopa County PM10 Nonattainment Area__________

Exceeding Monitor(s) ___Buckeye, Coyote Lakes, and West 43rd Monitors_______

AQI/High Wind/Dust Forecast (rolling three day forecast) Issued? 

 

 Yes No 

Type: _____PM10 Health Watch (issued between 10 am and noon, same day)________

In the spaces below, please provide information about the 72-hour period preceding the event, the 

day of the event, and the 72-hour period following the event. For a list of control measures for the 

planning area, see back of this form. Account for minimum 2 mile area around exceeding 

monitor(s). Please attach additional information if necessary. 

Complaints: 

No complaints for agricultural activities for all three areas during time frame, and two 

fields within radius of West 43rd and Durango monitors were not in crop production; no 

County complaints for Buckeye area; June 4th County complaint inspection of vacant lot 

for Coyote Lakes area; June 4th County complaint inspection_ of a dust control permit 

for West 43rd area. 

Inspections: 

June 4th four inspections of dust control permits under Rule 310 BACM measures for 

Buckeye area (no violations); June 2nd one inspection of Rule 316 point source for Rule 

316 BACM measures for Coyote Lakes area (no violations); June 3rd three inspections of 

dust control permits for Rule 310 BACM measures, June 5th two inspections – one for a 

dust control permit for Rule 310 BACM measures and one for Rule 316 source (no 

violations), June 6th five inspections of dust control permits for Rule 310 BACM 

measures (no violations) all for West 43rd area. 

Notices or Enforcement Actions: 

None for Buckeye area; one 60-day letter for unstable vacant lot under Rule 310.01 for 

Coyote Lakes area; one NOV issued on June 4th for trackout under Rule 310 and one 

NOV issued on June 5th for failure to install a wheel washer under Rule 316 both for 

West 43rd area.

X 
Regulating Agency(s) ADEQ (Agriculture); Maricopa County

Information Supplied By Emily Bonanni, ADEQ Planning Division, Compliance

 Section; Jo Crumbaker, Maricopa County Air Quality

 Department 

Date Completed October 14, 2009

FOR INTERNAL PURPOSES ONLY 

Reviewed by / date: _______________________________________________

Measures included in the Maricopa County PM10 5 Percent Plan 

(25 committed measures in parentheses) 

1. Extensive dust control training program (2). 

2. Dust managers/Coordinators at earthmoving sites < than or equal to 5 acres (3,16). 

3. Increase proactive Rule 310 and 316 inspections (9, 10, 44). 

4. Strengthen Rule 310 to promote continuous compliance (36 thru 38, 28). 

5. Conduct nighttime and weekend inspections (8). 

6. Ban leaf blowers from blowing debris into streets (21). 

7. Prohibit use of leaf blowers on unstabilized surfaces (45). 

8. Implement a leaf blower outreach program (22). 

9. Ban ATV use on high pollution advisory days (23). 

10. Pave or stabilize existing unpaved parking lots (25). 

11. Pave or stabilize unpaved road shoulders (28). 

12. Strengthen and increase enforcement of Rule 310.01 for vacant lots (31, 32) 

13. Recover costs for stabilizing vacant lots (33). 

14. Restrict and enforce vehicle use/parking on vacant lots (31, 32). 

15. Increase fines for open burning (34). 

16. Restrict use of outdoor fireplaces/pits/ambience fireplaces (35). 

17. Other wood burning restrictions in SB 1552 (47, 48). 

18. Repave or overlay paved roads with rubberized asphalt (53). 

Various additional SIP measures or sources: 

1. Agriculture – Agricultural Best Management Practices (AgBMP) Program 

2. Point sources – Permit Conditions (stack, fugitive, and area source emissions) 

3. Rule 310 and 310.01; sand and gravel – Rule 316 

4. Windblown, area sources – mobile, roadway, vacant lots, fires, et al. 

5. Maintenance of micro-scale Salt River stabilization/improvement 

6. Pave and stabilize public dirt roads and alleys 

7. Covered loads 

8. Registered subcontractors