Processed on 2024-03-04 13:07:56 PST.


Disclaimer: Data presented here come from a variety of sources and do not represent official EPA measurements. Please visit AirNow for official measurements.


Cumulative exposure to smoke is an important public health metric. This report summarizes the cumulative number of days air quality monitors in Indiana spent in each AQI category during the the month of April.

The tables below include only permanent monitors measuring PM2.5 and show cumulative exposure under existing NAAQS (National Ambient Air Quality Standards) and under the 2024 revised standards for PM2.5.

In the tables and plots below, ‘Old’ designates cumulative days calculated using the 2023 PM2.5 NAAQS while ‘New’ is calculated using the 2024 revised PM2.5 NAAQS. The impact of the NAAQS revision is quite clear.

April in Indiana

April 2014 – 12 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 214 97 0 0 0 0 30
New 136 175 0 0 0 0 30

April 2015 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 253 43 0 0 0 0 76
New 208 88 0 0 0 0 76

April 2016 – 27 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 311 60 0 0 0 0 32
New 236 135 0 0 0 0 32

April 2017 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 362 16 0 0 0 0 25
New 301 77 0 0 0 0 25

April 2018 – 27 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 336 32 0 0 0 0 35
New 284 84 0 0 0 0 35

April 2019 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 345 28 0 0 0 0 30
New 300 73 0 0 0 0 30

April 2020 – 27 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 270 86 0 0 0 0 47
New 193 163 0 0 0 0 47

April 2021 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 290 79 1 0 0 0 33
New 228 141 1 0 0 0 33

April 2022 – 13 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 161 19 0 0 0 0 6
New 115 65 0 0 0 0 6

April 2023 – 24 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 359 91 0 0 0 0 15
New 253 197 0 0 0 0 15