Processed on 2024-03-04 13:56:38 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 September.

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.

September in Pennsylvania

September 2014 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 41 19 0 0 0 0 2
New 26 34 0 0 0 0 2

September 2015 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 24 29 1 0 0 0 8
New 22 29 3 0 0 0 8

September 2016 – 31 permanent monitors

Processing error: Unable to calculate tables.

September 2017 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 49 41 0 0 0 0 3
New 37 53 0 0 0 0 3

September 2018 – 52 permanent monitors

Processing error: Unable to calculate tables.

September 2019 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 641 78 0 0 0 0 87
New 513 206 0 0 0 0 87

September 2020 – 75 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 113 7 0 0 0 0 4
New 106 14 0 0 0 0 4

September 2021 – 42 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1082 143 0 0 0 0 77
New 876 349 0 0 0 0 77

September 2022 – 45 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1061 113 0 0 0 0 97
New 920 254 0 0 0 0 97

September 2023 – 46 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1208 90 0 0 0 0 66
New 1017 281 0 0 0 0 66