Ms. Susan Hedman 

Regional Administrator 

U.S. Environmental Protection Agency Region V 

77 West Jackson Boulevard 

Chicago, IL 60604-3950 

Dear Ms. Hedman: 

Re: Designations under the 2012 National 

Ambient Air Quality Standard for Particulate 

Matter (PM2.s) 

The Indiana Department of Environmental Management (IDEM) has prepared this 

letter in response to United States Environmental Protection Agency's (U.S. EPA) August 

19, 2014, letter concerning proposed designations for the 2012 National Ambient Air 

Quality Standard (NAAQS) for particulate matter (PM2.5 ) . IDEM greatly appreciates the 

opportunity to provide comment on the proposed designations and would like to thank 

U.S. EPA for taking our recommendations into account when proposing these 

designations. 

U.S. EPA proposed to designate both Clark and Floyd Counties in the Louisville, 

KY-IN area as nonattainment because one of the monitors located in Clark County 

(180190006-Jeffersonville Walnut St.) measured a 2011 -2013 design value of 12.1 

I-Jg/m3, 0.1 I-Jg/m3 above the annual standard of 12.0 I-Jg/m3. IDEM is confident that this 

monitor will attain the PM2.s standard at the close of 2014. Through the third quarter of 

2014, the 2012-2014 design value for the Jeffersonville Walnut St. monitor is 11.9 

1-Jg/m3. A calculation of the fourth quarter critical value determined that a monitored value 

of 14.5 IJQ/m3 is needed in order for the monitor to be in violation of the standard at the 

close of 2014. A trend analysis of historical data (fourth quarters of 2009-2013) from the 

Walnut St. monitor indicates that a value of 10.8 I-Jg/m3 should be expected for the fourth 

quarter of 2014. This would result in the Walnut St. monitor attaining the standard. 

Figure 1 below shows that the fourth quarter average has been decreasing for the past 

five years and the 2014 projection is. well below the critical value needed for the monitor 

to violate the standard. It is also worth noting that the Walnut St. monitor has not 

recorded a fourth quarter of 14.5 I-Jg/m3 or higher within the past five years. 

Recycled Paper @ An Equal Opportunity Employer Please Recycle O 
-4 

- Linear (Average (llg/m3)) 

2009 2010 2011 2012 2013 2014 

IDEM will certify and submit the monitoring data as early as possible after the 

close of 2014, but certainly no later than January 30, 2015. This will provide U.S. EPA 

with the most current data in order to reconsider the classification for Clark and Floyd 

Counties prior to designation becoming effective. It is our understanding that if the 2012-

2014 design value for the Jeffersonville Walnut St. monitor is below the standard that 

U.S. EPA intends to designate both Clark and Floyd Counties as "unclassifiable" due to 

uncertainties with monitoring data collected by the Louisville Air Pollution Control District. 

Indiana agrees that this would be the most appropriate designation/classification for 

those counties. 

With regard to U.S. EPA's recommendation that both Lake and Porter Counties in 

Northwest Indiana be designated "unclassifiable" due to uncertainties with monitoring 

data within the Chicago-area monitoring network, IDEM understands U.S. EPA's 

rationale. However, the certified data collected by Indiana's network within Lake and 

Porter Counties should be sufficient for U.S. EPA to classify Lake and Porter Counties as 

attainment. 

I would like to thank you for the opportunity to provide additional feedback to U.S. 

EPA regarding the proposed designations for the 2012 PM2.s NAAQS. We look forward 

to working with your staff as U.S. EPA moves forward with future designations. If you 

have any questions regarding IDEM's response, please feel free to contact me at (317) 

232-8611 or Keith Baugues, Assistant Commissioner, Office of Air Quality, at (317) 232-

8222. 
TE/kb 

cc: John Summerhays, U.S. EPA 

Doug Aburano, U.S. EPA 

Keith Baugues, IDEM 

Sean Alteri, KDAQ