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Air Quality in Indiana

Air Quality in Indiana > Air Quality 101 Air Quality 101

April 15, 2015: How We Know Indiana’s Air Quality Is Good

Hoosiers need to understand that air quality in Indiana is good. This is true even when comparing our state with other areas with lower pollution levels. Regardless how we rank with other states, we know Indiana has good air quality by looking at the National Ambient Air Quality Standards.

Also referred to as NAAQS, the National Ambient Air Quality Standards are set by U.S. EPA. NAAQS standards set limits for six criteria air pollutants in the ambient air that the public breathes. The NAAQS standards include a margin of safety to protect all groups, including sensitive groups, from exposure to harmful levels of air pollution. Sensitive groups include the young, the elderly and those with health problems.

Just as air quality varies among various communities within our state, it will vary from state to state. Factors include geography, climate, population density, traffic, and business and industrial activities. Pollution that is carried here on the wind from distant sources—known as regional transport—also affects Indiana’s air quality. Just as Ohio should not and does not establish its clean air goals using Indiana air quality data—Indiana should not and does not use Ohio’s clean air data to establish clean air goals for the Hoosier state. However, Both Indiana and Ohio should and do establish their clean air goals based on the NAAQS standards.

Unfortunately, we often see independent reports that draw comparisons between states and mislead the public into believing Indiana’s air quality is unhealthy. To ensure the public receives all of the facts, I have used the NAAQS data to devise a grading system for air quality and have compiled an annual air quality report for all 50 states. My approach of assigning grades is similar to the American Lung Association.

Under my grading system, areas with air quality that is at least 20% better than the NAAQS receive an A. Areas between 10 and 20% better receive a B; areas that meet the standard or are up to 10% better receive a C; areas that exceed the standard by up to 10% receive a D; and areas that exceed the standard by more than 10% receive an F.

The States View of the Air (2015) report looks at 2011 through 2013 data for all states. 2014 data was not available for all states when I compiled the report. For this column, I was able to look at how Indiana fared during the latest three year period. Following are summaries for Indiana using data from 2012 to 2014. The table at the bottom of the column contains values to go along with the summaries.

Carbon Monoxide: Carbon monoxide (CO) has two standards, a 1-hour standard and an 8-hour standard. In the counties where CO is measured, all citizens see a level more than 20% better than the standard. In fact the 1-hour average is only 12.6 % of the standard, while the 8-hour average is 25.6% of the standard. As such, the air for CO should be rated as A.

Lead: While Indiana has one very small area in Muncie where the lead air quality standard is exceeded, nearly 90% of people live in areas where the lead values are more than 20% better than the standard. Another 10% live in areas that are better than the standard, but between 0 and 10%. The grade for lead should also be an A.

Nitrogen Dioxide (NO2): There are two standards for NO2, an annual standard and a one-hour standard. For people living in areas where NO2 is measured, the levels are more than 20% better than the standard. As such the pollutant should be rated as an A.

Ozone: Approximately 50% of people living in counties where ozone is measured breath air that is rated as B. Another 47% live in areas rated as C. Nearly 2% live in areas rated as A, while 1% live in areas rated as D. Based on this data, I would suggest that the pollutant should be rated as a C.

PM-2.5: There are two standards for PM-2.5, an annual standard and a 24-hour standard. For the annual standard, 55% of Hoosiers live in areas where PM-2.5 is rated as B, while 47% live in areas rated as C. Nearly 4% live in areas rated as A. Based on this information I would suggest a grade of B. For the 24-hour standard, 89% of Hoosiers live in areas rated as A, while the remainder live in areas rated as B. I would suggest that this rates an A.

Sulfur Dioxide (SO2): Over 75% of Hoosiers live in areas rated as A for SO2. Another 10% live in areas where the air is rated as C. About 3% live in areas where the air quality is rated as D. Another 12% live in areas rated as F. Based on this data, I would suggest a grade of C. More needs to be done to bring five areas into attainment and efforts are underway to make this happen.

If a state is meeting NAAQS standards, then it is doing a good job in protecting its citizens from harmful levels of air pollution. The true assessment of a state’s air quality is done by comparing it to the NAAQS. All measured air in Indiana met the six NAAQS standards in 2009, and air quality has continued to improve since then. When compared with the appropriate standards, it is obvious that Indiana’s overall air quality is good. In most cases, the air in Indiana is much better than the health based standards. There are still challenges with lead, ozone and sulfur dioxide as new limits have been adopted and additional revisions are anticipated. Indiana is committed to clean air for all Hoosiers and we believe that progress will continue under regulations and controls currently in place.

For a timely and accurate snapshot of air quality across our country, please read The States’ View of the Air (2015) report.

Grading Scale and Percent of Monitored Counties Achieving the Grade (2012-2014)
Pollutant A B C D F Indiana’s Overall Grade Average Population Weighted Average Percent of NAAQS
Current NAAQS Standard Air Quality Better than NAAQS by At Least 20% Air Quality Better than NAAQS by 10 to 20% Air Quality Meets NAAQS or 10% Better Air Quality Worse than NAAQS by Up to 10% Air Quality Worse than NAAQS by More than 10%
CO 1-hr (35 parts per million [ppm]) 100 0 0 0 0 A 4.4 12.6
8-hr (9 ppm) 100 0 0 0 0 A 2.3 25.6
Lead (1.5 micrograms per cubic meter [µg/m3]) 89.6 0 10.3 0 0 A 0.05 33.3
NO2 1-hr (100 parts per billion) 100 0 0 0 0 A 44 44
Annual (53 ppb) 100 0 0 0 0 A 10 18.9
Ozone (0.075 ppm) 1.7 50.3 46.8 1.3 0 C 0.067 89.3
PM Annual (12 µg/m3) 3.7 55.4 40.9 0 0 B 10.6 88.3
24-hour (35 µg/m3) 89.4 11.5 0 0 0 A 24.9 71.1
SO2 (75 ppb) 75.1 0 10.0 2.9 11.9 C 44 58.7

Comments can be sent to me at kbaugues@idem.in.gov.

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