Processed on 2024-03-04 13:57:10 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 December.

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.

December in Pennsylvania

December 2014 – 2 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 44 18 0 0 0 0 0
New 29 33 0 0 0 0 0

December 2015 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 18 12 2 1 0 0 29
New 15 15 2 1 0 0 29

December 2016 – 31 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 73 20 0 0 0 0 0
New 48 45 0 0 0 0 0

December 2017 – 3 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 63 27 2 1 0 0 0
New 41 49 2 1 0 0 0

December 2018 – 52 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 268 192 4 0 0 0 63
New 178 281 5 0 0 0 63

December 2019 – 28 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 517 282 14 1 0 0 54
New 379 420 14 1 0 0 54

December 2020 – 75 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 887 282 12 0 0 0 59
New 683 485 13 0 0 0 59

December 2021 – 42 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 770 448 1 0 0 0 52
New 516 702 1 0 0 0 52

December 2022 – 45 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 770 268 13 0 0 0 65
New 555 483 13 0 0 0 65

December 2023 – 46 permanent monitors

Good Moderate USG Unhealthy Very Unhealthy Hazardous Missing
Old 1033 301 3 0 0 0 13
New 817 517 3 0 0 0 13