Processed on 2024-03-04 13:55:52 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 Pennsylvania 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 Pennsylvania

April 2014 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 46 14 0 0 0 0 2
New 27 33 0 0 0 0 2

April 2015 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 54 6 0 0 0 0 2
New 45 15 0 0 0 0 2

April 2016 – 31 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 47 12 0 0 0 0 3
New 36 23 0 0 0 0 3

April 2017 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 78 10 0 0 0 0 5
New 65 23 0 0 0 0 5

April 2018 – 52 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 77 13 0 0 0 0 3
New 56 34 0 0 0 0 3

April 2019 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 456 60 0 0 0 0 73
New 390 126 0 0 0 0 73

April 2020 – 75 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 854 39 0 0 0 0 130
New 724 169 0 0 0 0 130

April 2021 – 42 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 840 152 1 0 0 0 278
New 626 366 1 0 0 0 278

April 2022 – 45 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1084 84 1 0 0 0 102
New 940 228 1 0 0 0 102

April 2023 – 46 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 860 196 1 0 0 0 59
New 602 454 1 0 0 0 59