Worcester Air Quality in 2024

In 2024, Worcester's air quality (Worcester, MA-CT area) had a median daily AQI of 37 (Good) across 366 monitored days. 2 days (0.5%) reached Unhealthy for Sensitive Groups or worse, 317 were Good, and the year's peak AQI was 122 (Unhealthy for Sensitive Groups). Ground-level ozone set the daily AQI on 279 of those days. The cleanest month of 2024 was January (median AQI 33, 0 days above 100) and the worst was June (median 44, 2 days above 100, peak 122).

37
Median AQI
Good
2
Days above AQI 100
0.5% of 366 days
54
90th percentile AQI
worst 1 day in 10
122
Peak AQI
Unhealthy for Sensitive Groups
O3
Main pollutant
279 of 366 days
317
Good days
86.6% of days
  • Good: 86.6%
  • Moderate: 12.8%
  • Unhealthy for Sensitive Groups: 0.5%
  • Unhealthy or worse: 0.0%

Reduce Indoor Ozone in Worcester

Today's main pollutant in Worcester is ground-level ozone (AQI 32). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.

Recommended: Levoit Core 300True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft

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QUICK ANSWER

How was Worcester's air quality in 2024?

Good on a typical day: median AQI 37, with 2 days above AQI 100 out of 366 monitored — the 5th cleanest of 7 years on record for the area.

  • Peak AQI in 2024: 122 (Unhealthy for Sensitive Groups).
  • Ground-level ozone was the main pollutant on 279 days.
  • Cleanest month: January; worst: June.

Frequently asked questions

What was the average AQI in Worcester in 2024?

EPA's Air Quality System puts Worcester's (Worcester, MA-CT) median daily AQI for 2024 at 37, which is Good. 2 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 122.

Which month had the worst air quality in Worcester in 2024?

The cleanest month of 2024 was January (median AQI 33, 0 days above 100) and the worst was June (median 44, 2 days above 100, peak 122).

Was 2024 a good or bad year for Worcester's air?

Among the 7 years EPA has published for the area (2019–2025), 2024 ranks 5th cleanest by days above AQI 100. 2024's median of 37 is below the area's typical annual median of 43.

Worcester month by month in 2024

Worcester air quality month by month, 2024 (Worcester, MA-CT, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
Januarycleanest3133058O3
February2939058O3
March3137049O3
April3040058O3
May3138080O3
Juneworst30442122O3
July3144084O3
August3144074PM2.5
September3035058O3
October3133067O3
November3033041O3
December3134063O3

How 2024 compares

Among the 7 years EPA has published for the area (2019–2025), 2024 ranks 5th cleanest by days above AQI 100.

2024's median of 37 is below the area's typical annual median of 43.

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

Right now in Worcester

The latest EPA AirNow observation puts Worcester's AQI at 32 (O3). The figures above are multi-year annual statistics, not today's reading.

View current Worcester air quality →

Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Worcester, MA-CT), 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.