Mr. Jared Blumenfeld, Regional Administrator

U.S. Environmental Protection Agency, Region IXMail Code ORA-1

75 Hawthorne Street

San Francisco, CA 94105

Re: Support Documentation Regarding Air Quality Designation for the Revised National Ambient

Air Quality Standard for Lead

Dear Mr. Blumenfeld:On September 25, 2013, the Honorable Janice K. Brewer, Governor of Arizona, submitted a letter to the

U.S. Environmental Protection Agency (EPA) recommending that the Hayden, Arizona area not be re

designated as nonattainment for the Revised National Ambient Air Quality Standard (NAAQS) for lead.

The Arizona Department of Environmental Quality (ADEQ) is submitting the enclosed Technical Support

Document (TSD) in support of that recommendation. The purpose of the TSD is to describe the

relationship between sulfur dioxide (S02) and lead concentrations and demonstrate the effectiveness of

control technology in reducing lead emissions within the ASARCO Hayden Copper Smelter.

In June 2012, ASARCO completed the installation of additional controls at the facility. ADEQ reviewed

the data collected since the installation and determined that lead concentrations at the ADEQ Globe

Highway monitoring site have decreased by approximately 40 percent. In addition, there have been no

violations of the lead standard since June 2012. The decrease in lead concentrations supports ADEQ’s

assertion that the area not be re-designated as nonattainment for the lead NAAQS. Please see the attached

TSD for a detailed analysis.

ADEQ respectfully submits the enclosed TSD as supplemental information to the Governor’s

recommendation that the Hayden area not be re-designated as nonattainment for the lead NAAQS. If you have any questions, please contact Steve Calderon, State Implementation Plan Section Manager, at (602)

771-2352.

:7

SncereIy7

Eric C/Massey

Dir tor, Air Quality

Enclosure

cc: Colleen McKaughan, EPA Region IX, w/enclosure

Southern Regional Office

400 West Congress Street • Suite 433 • Tucson, AZ 85701

(520) 628—6733

Printed on recycled paper

Relationship Between Ambient

Sulfur Dioxide and Lead

Concentrations

Hayden, Arizona

Arizona Department ofEnvironmental Quality

August23, 2013
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1 - Globe Highway Pb concentrations, expressed as 3-month rolling averages, from January,

2011 through June, 2013. The red dashed line represents the Pb NAAQS of 0.15 jig/rn 3.April, May,

and June data from 2013 are considered preliminary at this point due to incomplete quality

assurance procedures.Previous, unpublished work conducted by the Arizona Department of Environmental

Quality has shown that Pb and Sulfur Dioxide (SO 2)concentrations measured at the

Globe Highway site in Hayden, AZ have a strong, direct relationship. This relationship

was analyzed in greater detail in an attempt to determine whether control devices

installed at the ASARCO facility in July, 2012, have resulted in reductions in Pb

concentrations measured at the Globe Highway site. If the reductions in ambient Pb

concentrations are a result ofthe installation of control technologies that were intended to

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maximum was below that ofthe Pb NAAQS (0.15 IgIm 3). This information is displayed

graphically below in Figure 1. Based on the maximum 3-month average for each

calendar year, ambient Pb concentrations measured at the Globe Highway site have

decreased by approximately 56% between 2011 and 2013. Since the installation of

additional controls in July, 2012, ambient Pb concentrations at the Globe Highway site

have decreased by approximately 40%.

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Globe Highway Pb Concentrations: 3.month Rolling Averages

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concentrations measured at the Globe Highway station in Hayden, AZ between January

15th, 2011 and June 30th, 2013. It is apparent that there is a strong, direct relationship

between SO2and Pb concentrations as both pollutants rise and fall together. Thecorrelation coefficient between the SO2and Pb data is 0.78, confirming the very strongrelationship between the two pollutants. While the correlation between the Pb and SO2data is high, Figure 2 indicates a change in the relationship occurring around July, 2012,

as the separation between the SO2concentrations (yellow line) and Pb concentrations

(blue line) appears to increase.

Figure 2 - Pb and S02 data from the Globe Highway monitors in Hayden, Arizona for the period

January 15, 2011 to June 30,2013

This relationship was examined further by examining the ratio of SO2concentrations to

Pb concentrations over time. Figure 3 shows the change in this relationship much clearer.

Given the relatively large SO2concentrations compared to that of Pb concentrations, the

ratio is quite high, with SO2concentrations being approximately 263 times that of Pbconcentrations during the first period ofthe data series (Jan 15, 2011 — June 30, 2012).However, one can see a very abrupt change in the ratio, beginning around July, 2012.

The average SO2/Pb ratio increased sharply during the second period of the time series(July 1, 2012 — June 30, 2013) with an average ratio of approximately 719. Thissignificant change in the ratio between the two indicates a substantial change in the

relationship between Pb and SO2concentrations measured at the Globe Highway site.The timing ofthe abrupt change in the SO2to Pb ratio coincides with the installation of

Globe Highway Lead vs S02

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installed control devices were effective in reducing ambient Pb concentrations in Hayden,

AZ, additional data would be needed to verify that the Globe Highway Pb monitor

continues to attain the Pb NAAQS.

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Figure 3 -Temporal variation of the relationship between SO2and Pb as measured by calculating the

ratio between SO2and Pb concentrations. An abrupt change in the relationship between SO2and Pb

concentrations can be seen beginning around July, 2012, when control devices were installed.

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Globe Highway S02! Pb Ratio

(excludes low S02 days < 5 ug!m3)

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