From: "Shawn B. Kendall" <Kendall.Shawn@azdeq.gov>

To: Gwen Yoshimura/R9/USEPA/US@EPA, "Steven E. Peplau" <Peplau.Steven@azdeq.gov>

Cc: Scott Bohning/R9/USEPA/US@EPA, Meredith Kurpius/R9/USEPA/US@EPA, MichaelA Flagg/R9/USEPA/US@EPA

Date: 04/01/2010 04:11 PM

Subject: Re: ASARCO PB site language

Excellent summary. And I would concur if a second site is chosen it should be west of the facility. 

From: Yoshimura.Gwen@epamail.epa.gov <Yoshimura.Gwen@epamail.epa.gov>

To: Shawn B. Kendall; Steven E. Peplau 

Cc: Bohning.Scott@epamail.epa.gov <Bohning.Scott@epamail.epa.gov>;

Kurpius.Meredith@epamail.epa.gov <Kurpius.Meredith@epamail.epa.gov>; flagg.michaela@epa.gov

<flagg.michaela@epa.gov>

Sent: Thu Apr 01 16:06:44 2010

Subject: Re: ASARCO PB site language 

Hi Shawn,

See what you think of the following. Much thanks to Scott for the write up!

Thanks,

Gwen

ASARCO Hayden Pb monitor: Rationale for siting ASARCO Hayden Pb monitor at Globe Highway 

Station based on discussion with Shawn Kendall, ADEQ, 2010-03-31

Source-oriented lead (Pb) monitoring is required for the ASARCO copper smelter in Hayden, Arizona. 

ADEQ chose the Globe Highway Station site after an analysis that considered source emission 

characteristics, past monitoring, and the topography and meteorology of the facility location. 

A 1987 source apportionment study using the Chemical Mass Balance model concluded that 80% of the 

PM10 Pb came from process fugitive emissions within the smelter ("Source Apportionment of Suspended 

Particles and Toxic Elements in Hayden, Arizona, Final Report", NEA Inc., April 15, 1987). Direct 

observation by ADEQ staff confirmed that particulate plume emanates principally from the smelter 

building itself, rather than from other sources such as ore handling facilities or re-entrained dust from 

storage piles. Because of the high temperatures involved in the smelting process, this plume is buoyant 

and has substantial vertical velocity, reaching to 100 feet or more above ground level. Unlike for nonbuoyant ground level plumes, the highest ground level concentrations from such a buoyant plume would 

not be expected to occur immediately adjacent to the facility.
Because the bulk of SO2 emissions are also thought to be emitted as buoyant fugitives from the smelter 

building, 1970's monitoring of SO2 is relevant for Pb. (Since the stack is 1000 feet tall, SO2 impacts from 

stack emissions occur farther away and are diluted by the time stack plume reaches the ground.) At that 

time SO2 monitoring was conducted at twelve different monitor locations; Globe Highway Station was 

found to have the highest concentrations. Because of the similar emission characteristics of SO2 and Pb 

fugitives, this suggests Globe Highway may also have the highest concentrations for Pb.

The ASARCO Hayden smelter is located in very complex terrain, with the Gila River making a winding 

semi-circle east to south of the facility, and intersected by the San Pedro River valley from the south. The 

facility itself is elevated relative to the valleys; there is a 200 foot hill just south of the facility, and 

mountains rising toward the north/northeast. The varied terrain causes complex wind flow. Within and 

adjacent to the river valleys, drainage winds tend to dominate at night under stable conditions, toward the 

west on the south and west of the facility, and toward the south on the east of the facility. However, given 

the buoyancy of the smelter building fugitive plume, and the facility's elevated location, emissions typically 

rise above these surface flows and would not be expected to result in high Pb concentrations. During the 

day under convective conditions, good vertical mixing causes polluted air to reach the ground. The 

vertical mixing also causes the flow to be coupled with winds aloft, which generally flow toward the east. 

As was the case for SO2, these are the conditions expected to lead to high Pb concentrations and that 

also carry the plume east, toward the Globe Highway Station.

Should placement of another Pb-TSP monitor be possible, EPA supports placement west of the smelter 

building, to capture winds moving east to west over the smelter area.

________________________________________ 

Gwen M. Yoshimura 

Air Quality Analysis Office 

Environmental Protection Agency, Region 9 

Phone: 415.947.4134 

Email: yoshimura.gwen@epa.gov

mailing address: 

U.S. Environmental Protection Agency 

Air Quality Analysis Office (AIR-7) 

75 Hawthorne Street 

San Francisco, CA 94105