May 2013: The Status of Air Quality in Indiana

This is the sixth article in a series about air quality in general and how it applies to Indiana. I am planning to publish an article every two weeks to cover air pollution topics. This article will discuss the status of air quality in Indiana.

So how clean, or dirty, is Indiana’s air? This is the question that started this series and I thought it was time that I provided an answer. The appropriate question is how does Indiana’s air quality compare to the national ambient air quality standards (NAAQS). An inappropriate question is how does the air quality in Indiana compare to that of other states. I will address that issue in another column.

The data period that I will use to answer this question is the most current three years of data (2010 – 2012). During this period, Indiana had six carbon monoxide (CO) monitoring sites operating. Each site was meeting the 1- and 8-hour NAAQS for CO. Levels are related to automobile emissions and are expected to continue dropping over time.

During this period, Indiana had ten lead monitoring sites operating. One site in Muncie has levels that are above the NAAQS. We believe the area impacted is very small with at most 600 people living within the area above the NAAQS. Levels of lead continue to decrease. Controls that are being installed at the nearby secondary lead smelter are expected to bring air quality levels below the standard within a year or two.

During this period, Indiana had four nitrogen dioxide (NO2) sites operating. All sites are well below the 1-hour NAAQS. Future levels are expected to decrease due to cleaner automobiles or reductions in emissions at utilities.

During this period, Indiana had 40 ozone monitoring sites operating. Of these, five sites had design values that exceeded the current NAAQS. This is the first year in several where design values have exceeded the NAAQS. These are believed to be related to a large number of hot summer days in 2012. The counties with design values above the standard are Clark, Floyd, Greene, LaPorte and Perry.

During this period, Indiana had 33 PM-2.5 sites operating. All sites met both the 24-hour and annual PM-2.5 NAAQS. Levels in the future are expected to decrease due to emission reductions being made at utilities. The U.S. Environmental Protection Agency (U.S. EPA) has lowered the annual PM-2.5 standard. It is possible that a few counties may exceed the new standard in 2015 when nonattainment designations are finalized.

During this period, Indiana had 20 sulfur dioxide (SO2) monitoring sites operating. All sites met the annual NAAQS. Six sites did not meet the 1-hour NAAQS. These included sites in Daviess, Marion, Morgan, Pike and Vigo counties. Future levels are expected to drop below the NAAQS. IDEM will be working with utilities in these counties to reduce sulfur dioxide emissions enough so that air quality levels are met.

Below is a score card for the standards and monitors involved. Overall Indiana meets the NAAQS at most all monitors for most pollutants. Our current challenges are for ozone and sulfur dioxide in a few counties.

Indiana Air Quality Summary (2010 – 2012 Data)
Pollutant Standard Number of Sites Number of Sites
Meeting the Standard
CO 1-hour 6 6
CO 8-hour 6 6
Lead Quarterly 10 9
NO2 1-hour 4 4
Ozone 8-hour 40 35
PM-2.5 Annual 33 33
PM-2.5 24-hour 33 33
SO2 Annual 20 20
SO2 1-hour 20 14

Keith Baugues

Air Quality 101 articles March 13: Criteria Pollutants and National Ambient Air Quality Standards and April 13: Ambient Monitoring in Indiana provide an introduction to the pollutants discussed in this article, the National Ambient Air Quality Standards (NAAQS), and ambient