SIERRA 

CLUB 

I· 0 U N D E 0 I 8 92 

September 15'h, 2015 

Scott Mathias 

1\ssociate Director 

Air Quality Policy Division 

U.S. Environmental Protection Agency 

Research Triangle Park, NC 27711 

Re: Air Dispersion Modeling of Illinois Sulfur Dioxide Pollutio n 

Dear Associate Director Iathias, 

Sierra Club urges the U.S. Environmental Protection Agency to designate the areas 

surrounding the Newton, Joppa, and Manon coal-fired power plants as nonattainment under the 

sulfur dioxide ("S02") National Ambient rill Quality Standard ("NAAQS"). Air dispersion 

modeling recently conducted by Wingra Engineering, S.C. on behalf of Sierra Club demonstrates 

that ambient air concentrations in these areas exceed the NAr\Q , which is the maximum 

concentration of air pollution allowed to protect public health. 

("7irst, air dispersion modeling demonstrates that S02 emissions from the Marion Generating 

Station in Illinois have caused downwind S02 ambient air concentrations to exceed the 75 parts per 

billion, o r 196 micrograms per cubic meter, NAAQS. In particular, the modeling of actual 

emissions from this facility alone shows peak concentrations as high as 288.8 micrograms per cubic 

meter. Accordingly, the U.S. Environmental Protectio n Agency should designate the area 

surrounding the l\fario n coal-fired power plant as nonattainmcnt under the NAJ\QS. 

Second, air dispersion modeling demo nstrates that actual 0 2 emissions from the Joppa 

coal-fired power plant in Illinois have caused downwind peak S02 ambient air concentrations as 

high as 222 micrograms per cubic meter. When the acrual emissions o n two other sources of S02 

that arc located within 50 kilometers of the Joppa Steam Electric ration are included, the peak 

concentration is as high as 250.4 micrograms per cubic meter. Therefore, the U.S. Environmental 

Protection Agency should also designate the area surrounding the Joppa coal-fired power plant as 

nonattainmcnt under tl1e NAAQS. 
Letter to Associate Director .i\tfathias 

September 15, 2015 

Page 2 

Finally, air dispersion modeling demonstrates that S02 emissions from the Newton Power 

Station, along with actual emissions from another large S02 source that is within 50 kilometers of 

the plant, also have caused downwind S02 ambient air concentrations to exceed the NAAQS. 

Specifically, the modeling shows cumulative peak concentrations for Newton Power Station as high 

as 535.8 micrograms per cubic meter. Accordingly, the U.S. Environmental Protection Agency 

should designate the area surrounding the Newton coal-fired power plant as nonattainment under 

the NAAQS. 

Enclosed, please find the results of the modeling analyses, along wid1 the corresponding 

modeling input and output files. 

Sierra Club urges the U.S. Environmental Protection Agency to consider this information as 

it W1dertakes area designations in Illinois for the 2010 revised prin1ary so2 NAAQS. Tlus 

information is also being provided to both EPA Region 5 and to appropriate personnel at the 

Illinois Environmental Protection Agency. In the meantime, please let us know if we can provide 

any additional information. 

Thank you for your attention to and consideration of this matter, and please do not hesitate 

to contact us if you would like to discuss further. 

Sincerely, 

Kristin A. Henry 

Sierra Club 

85 Second Street, 2"d Floor 

San Francisco, CA 94105 

415-977-5716 

kristin.henry@sierraclub.org 
Letter to Associate Director Mathias 

September 15, 2015 

Page 3 

Greg Wannier 

Sierra Club 

85 Second Street, 2"d Floor 

San Francisco, CA 94105 

415-977-5646 

greg.wannier@sierraclub.org 

Faith E. Bugcl 

Attorney at Law 

1004 Mohawk 

Wilmette, IL 60091 

312-282-9119 

fbugel@gmail.com