Worcester, Massachusetts Air Quality
Worcester County, Massachusetts (MA)
→ Stableover 10 years
10-Year AQI Trend
The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days).
Air Quality Day Breakdown
Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).
Year-by-Year Data
| Year | Median AQI | 90th Pct | Max AQI | Good Days | Moderate | Unhealthy+ | Pollutant |
|---|---|---|---|---|---|---|---|
| 2023 | 39 | 58 | 148 | 268 | 93 | 4 | Ozone |
| 2022 | 45 | 59 | 100 | 228 | 137 | 0 | PM2.5 |
| 2021 | 45 | 59 | 125 | 218 | 144 | 3 | PM2.5 |
| 2020 | 43 | 58 | 90 | 257 | 109 | 0 | PM2.5 |
| 2019 | 45 | 59 | 93 | 238 | 127 | 0 | PM2.5 |
| 2018 | 40 | 61 | 129 | 265 | 96 | 4 | Ozone |
| 2017 | 40 | 56 | 143 | 288 | 74 | 3 | Ozone |
| 2016 | 41 | 60 | 143 | 285 | 77 | 4 | Ozone |
| 2015 | 40 | 61 | 93 | 266 | 99 | 0 | Ozone |
| 2014 | 43 | 62 | 115 | 242 | 122 | 1 | Ozone |
What This Means for Worcester County Residents
Worcester, Massachusetts has received an Air Quality Grade of C (62/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 39 falls in the "Good" range.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 1 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity. The American Lung Association's State of the Air report provides additional context on long-term health risks from air pollution exposure.
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Frequently Asked Questions
Worcester, Massachusetts has a current median AQI of 39, which falls in the "Good" range. The area has received an Air Quality Grade of C (62/100) based on 10 years of EPA monitoring data.
Air quality in Worcester, Massachusetts is stable over the past decade. The median AQI has changed by -4 points from 2014 to 2023.
Worcester, Massachusetts averages 1 unhealthy air quality days per year over the past 5 years. On these days, sensitive groups including children, the elderly, and those with respiratory conditions should limit outdoor activity.
The primary pollutant affecting Worcester, Massachusetts is Ground-Level Ozone. This is the dominant contributor to elevated AQI readings in the Worcester County area.
Worcester, Massachusetts averages 1 unhealthy air days per year. This is relatively low, making it a reasonable choice for asthma sufferers. The primary pollutant is Ground-Level Ozone, which is a known asthma trigger.
With a median AQI of 39 (Good), outdoor exercise in Worcester, Massachusetts is generally safe year-round. Worcester, Massachusetts averages 1 days per year when athletes should move workouts indoors.