Worcester Air Quality in April
Across 2019–2025, Worcester's April air quality had a median AQI of 44 (Good) over 210 monitored days in the Worcester, MA-CT area. 0.5% of April days (1 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 71.9% of days. The cleanest April on record here was 2024 (median AQI 40, 0 days above 100) and the worst was 2023 (median 47, 1 day above 100, peak AQI 112).
- Good: 81.0%
- Moderate: 18.6%
- 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 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Worcester in April?
Good on a typical day: median AQI 44 across 2019–2025, with 0.5% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓81.0% of April days were Good (AQI 0–50), 18.6% Moderate (51–100).
- ✓1 day of 210 reached AQI 101+; the April peak was 112.
- ✓Best April: 2024; worst April: 2023.
Frequently asked questions
What is the air quality like in Worcester in April?▾
Across 2019–2025, the median daily AQI in Worcester in April was 44 (Good). 81.0% of days were Good, 18.6% Moderate, and 0.5% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Worcester?▾
A typical April day in Worcester sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
Which pollutant causes Worcester's April air quality problems?▾
Ground-level ozone set the daily AQI on 71.9% of April days in Worcester. The highest April AQI recorded in 2019–2025 was 112 (Unhealthy for Sensitive Groups), in 2023.
Worcester April air quality, year by year
Worcester April air quality by year (Worcester, MA-CT, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 44 | 0 | 58 | O3 |
| 2020 | 30 | 44 | 0 | 55 | O3 |
| 2021 | 30 | 46 | 0 | 74 | O3 |
| 2022 | 30 | 44 | 0 | 55 | PM2.5 |
| 2023worst | 30 | 47 | 1 | 112 | O3 |
| 2024cleanest | 30 | 40 | 0 | 58 | O3 |
| 2025 | 30 | 45 | 0 | 87 | O3 |
What April air means in Worcester
A typical April day in Worcester sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
April's median AQI of 44 is in line with Worcester's whole-year median of 43, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Worcester runs in line with the national April norm; 0.5% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Worcester's spring season (March, April, May); the spring page pools all three months.
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 month 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.