# SIERRA CLUB I · 0 U N D E 0 I 8 92 September 

### 15 'h, 2015 Scott Mathias 1 \ ssociate Director Air Quality P o licy Division U.S. E nv ironmental Protection Agency Re searc h Triangle Park, NC 

### 27711 Re : 

### Air Dispersion Modeling of Illinois Sulfur Dioxide P o lluti o n Dear Assoc iate Director

**Iathias,** S ierra Club urges the U .S. Environmental Protecti o n Age nc y to de signate the areas surroundin g the Newto n , Joppa, and Manon coal-fired p o wer plants a s n o nattainment under the sulfu r dioxide ("S0 2 ") National Ambient r ill Quality Standard ("NAAQS") . Air dispersion m o deling recently conducted by Wingra Engineering, S.C. o n behalf o f 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. ( "7irs t, air dispers ion modeling demonstrates that S0 2 emis sions from the Marion Generating S tati o n in I llin o is have caused downwind S0 2 ambient air conce ntrati ons to exceed the 75 parts per billi o n, o r 

### 196 microg rams per cubic meter, NAAQS. In particu l ar, the modeling of actual emissions from thi s facility alone shows peak concentrati o n s a s hig h as 288.8 micrograms per cubic meter. According l y, the U . S . Environmental Pro tecti o n Agency s ho uld de signate the area su rrou nding the l\ fari o n coal-fired power plant as nonattainmcnt under the NAJ\ QS. Second, air dispersion modeling demo n stra te s that actual 0 2 emissions from the J o ppa coal

- fired p ower plant in Illino is have cau sed d ownwind peak S0 2 ambient air concentration s as high as 

### 222 micrograms per cubic meter. When the acrual e mi ss io n s o n t wo o ther sources of S0 2 that arc l ocated within 

### 50 kilo meters of the Joppa Stea m E lectric ratio n are included, the peak concentration is as high as 

### 250.4 micrograms per cubic m eter. Therefore, the U.S. Environmental Pro te ctio n Age nc y sh o uld al so de signate the area surroundin g the J o ppa coal

- fired power plant as nonattainmc nt under tl1e NAAQS .

### Letter to Associate Director .i\t fathias 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 S0 2 

### 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 corre sponding 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 Re gion 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 yo ur attention to and consideration of this matter, and please do not hesitate to contact us if you would like to discus s further
. Sincerely,

Kristin A. Henry Sierra Club 85 Second Street, 2"d Floor San Francisco, CA 94105 415

-977

- 5716 kristin.henry @s ierraclub.orgLetter to Associate Director Mathias September 15, 2015 Page 3 Greg Wannier Sierra C lub 85 Seco nd Stree t, 2"d Floor San Fran cisco, CA 94105 415-9 77- 5646 greg.wannier @s ierraclub. o r g Faith E. Bugcl Attorney at Law 1004 Mohawk Wilmette, IL 60091 312 - 282 - 9119 fbugel @ gmail.com