Rochester Air Quality in 2021

In 2021, Rochester's air quality (Rochester, NY area) had a median daily AQI of 44 (Good) across 365 monitored days. 0 days (0.0%) reached Unhealthy for Sensitive Groups or worse, 239 were Good, and the year's peak AQI was 100 (Moderate). Fine particulate matter (PM2.5) set the daily AQI on 224 of those days. The cleanest month of 2021 was September (median AQI 35, 0 days above 100) and the worst was December (median 52, 0 days above 100, peak 64).

44
Median AQI
Good
0
Days above AQI 100
0.0% of 365 days
61
90th percentile AQI
worst 1 day in 10
100
Peak AQI
Moderate
PM2.5
Main pollutant
224 of 365 days
239
Good days
65.5% of days
  • Good: 65.5%
  • Moderate: 34.5%
  • Unhealthy for Sensitive Groups: 0.0%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How was Rochester's air quality in 2021?

Good on a typical day: median AQI 44, with 0 days above AQI 100 out of 365 monitored — the 4th cleanest of 7 years on record for the area.

  • Peak AQI in 2021: 100 (Moderate).
  • Fine particulate matter (PM2.5) was the main pollutant on 224 days.
  • Cleanest month: September; worst: December.

Frequently asked questions

What was the average AQI in Rochester in 2021?

EPA's Air Quality System puts Rochester's (Rochester, NY) median daily AQI for 2021 at 44, which is Good. 0 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 100.

Which month had the worst air quality in Rochester in 2021?

The cleanest month of 2021 was September (median AQI 35, 0 days above 100) and the worst was December (median 52, 0 days above 100, peak 64).

Was 2021 a good or bad year for Rochester's air?

Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100. 2021's median of 44 is in line with the area's typical annual median of 42.

Rochester month by month in 2021

Rochester air quality month by month, 2021 (Rochester, NY, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
January3149080PM2.5
February2852060PM2.5
March3141065O3
April3042074O3
May31390100O3
June3048097O3
July3146092PM2.5
August3152067PM2.5
Septembercleanest3035057O3
October3137055PM2.5
November3038061PM2.5
Decemberworst3152064PM2.5

How 2021 compares

Among the 7 years EPA has published for the area (2019–2025), 2021 ranks 4th cleanest by days above AQI 100.

2021's median of 44 is in line with the area's typical annual median of 42.

Activity-specific thresholds: running, cycling, kids' sports.

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Rochester, NY), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.