Michael Flagg

USEPA Region 09 Mail Code: AIR 7

75 Hawthorne Street

San Francisco, CA 94105

RE: Relocation of the Pinnacle Peak and Mesa sites

Mr. Flagg:

The purpose of this letter is to inform you that the Maricopa County Air Quality Department (MCAQD) proposes to shut down the Mesa site (04-013-1003) as of January 31, 2012 and move the PM10 and PM25 monitors to the Tempe site (04-013- 4005). These two new monitors will be continuous. The Tempe site is the best location for the monitors because of the relative short distance between the sites and similarities

in pollution sources and population (see attached report). Additionally, both monitors will be established in EPA AQS database as special purpose monitors and will be evaluated after one year of data has been collected. The start date for the new monitors

will be February 24, 2012.

Additionally, MCAQD shut down the Pinnacle Peak site (04-013-2005) on November 18, 2011 after receiving a letter from the land owner to remove the site (see attached). MCAQD is currently in negotiations with the same land owner to reestablish the site

within a mile of the original location. The start date for the new Pinnacle Peak site is

August 2012.

Regards,

Ben Davis

Air Monitoring Manager

Enc.

cc: William Wiley MCAQD

Eric C. Massey ADEQ

Lindy Bauer MAG

Protecting our most vital, natural resource; air. FWcIEllvED

www.maricopa.gov/ag FEB 13 2012 —
Background:

The Maricopa County Air Quality Department’s (MCAQD) Mesa air pollution monitoring site,

AQS# 04-013-1003, is located at 310 S. Brooks Avenue in Mesa, AZ. This location is a City of

Mesa property housing the Brooks Reservoir, an underground water storage site. The City of

Mesa provides us a small room within their maintenance buildings in addition to space on the

roof to run our equipment (Figure 1). This monitoring site has been continually operating at

this location since 1978 and currently monitors PM1O, and PM2.5. The CO monitor iscontinuous, but both the PM1O and PM2.5 monitors are filter-based Federal Reference Methods

operating on a 1-in-6 and 1-in-3 day operating schedule, respectively. There are alsometeorological monitors on site, including wind speed and direction.

Figure 1. Maintenance building at the City of Mesa Brooks Reservoir housing the Mesa monitoring site.

The pollution design values at the Mesa site are relatively low compared with the rest of the

network; the 2005-2009 average design value for the three parameters is listed in Table 1. The

last time that there was an exceedance at the Mesa site of the CO standard was in 1980. The

only exceedance of the PM1O standard occurred in 2003, while the only exceedance of the

PM2.5 standard occurred on July 5, 2011, during a summer dust storm.

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value (2005-2009) being highest design value)

CO 3.02 PPM #10 out of 13 monitoring sites

PM1O 85.8 ig/m 3 #13 out of 15 monitoring sites

PM2.5 17.8 ig/m 3 #4 out of 4 monitoring sites

Construction:In August 2011, MCAQD was notified by the City of Mesa of pending major construction to

upgrade the pumping infrastructure at the Brooks Reservoir site. All electrical power to the site

will be cut while construction is underway, which is scheduled to begin in February 2012 and

could be underway for over six months. Following completion of the construction and

resumption of power at the site, MCAQD will construct a new site close to the original location.

This is expected to take up to two months. Figure 2 shows construction equipment being

gathered at the Brooks Reservoir.

Figure 2. Construction material being gathered at the Brooks Reservoir site in January 2012.

Construction is expected to commence on February 1, 2012.

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Figure 3. Tempe Monitoring Site, the proposed temporary location of the Mesa PM1O and PM2.5

monitors.

MCAQD proposes that Tempe is an appropriate substitute for Mesa not only because it is

closest, but also because many source characteristics and population demographics are similar.

Table 2 shows data from the 2008 MCAQD emissions inventory, with spatial data taken from

the 2010 MCAQD Network Assessment. A four-mile buffer was drawn around each site and

known PM1O and PM2.5 emission sources were summed and averaged for their annual

emissions. Tempe is similar to Mesa in PM1O emission, but PM2.5 emissions are more than

three times greater. South Scottsdale has far fewer PM1O and PM2.5 emissions.

Table 2. Data from the 2008 MAQD Emissions Inventory on PM1O and PM2.5 sources within a four

mile radius of monitoring site.

Site Average Sum of PM1O Average Sum of PM2.5

Annual PM1O Annual PM2.5 Annual Annual

Emissions Emissions Emissions Emissions

Mesa 1,397 lbs 96,418 lbs 797 lbs 55,008 lbs

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p

uth Scottsdale.

Table 3-Traffic Counts (from 2007) within a four-mile radius of monitoring site.

Site Arterial Road AWT Freeway AWT Average Traffic

Mesa 27,782 167,141 97,462

Tempe 28,599 161,609 95,104

South Scottsdale 20,972 154,993 87,983

Table 4 displays the sum and density of population within a four-mile radius of the monitoringsites. Mesa represents significantly more population than the other sites, but Tempe is the most

similar among nearby sites.

Table 4-Population data (from the 2000 Census) within a four-mile radius of monitoring site.

Site Sum of Population Population Density

(within Census Blocks) (population per km2)

Mesa 263,948 2,615

Tempe 210,610 2,605

South Scottsdale 131,772 2,113

Conclusion:

MCAQD proposes to move the Mesa PM1O and PM2.5 filter based monitors to the Tempe site.

These two new monitor will be continuous. The Tempe site is the best option for the monitors

because of the relative short distance between the sites and similarities in pollution sources and

population.

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Maricopa County Air Quality Department

2145 South 11th Ave.

Suite 170

Phoenix,AZ 85007

Attention: Ben Davis, Air Monitoring Manager

RE: Equipment located at 25000 N. Windy Walk Dr.

Mr. Davis,

Troon Country Club would like to discontinue its cooperative with the.county to host the air quality equipment. Please have the equipment removed at your earliest convenience.

Thank you,

Jo iA. ewell

Co Her

OCX 1J.. Windy Wk Dvu b Sco Ari 5255 ‘(40 5-43iti F)) 83-5233

www.trooncc.com