Metro area air quality · 2024
Hartford-West Hartford-East Hartford, CT
Median AQI 40 (Good). 75.4% of monitored days rated Good across this metro's EPA monitoring network.
- 40
- Median AQI
- 75.4%
- Good-air days
- 1
- Unhealthy days
- 53%
- Cleaner than US metros
Aggregated from EPA Air Quality System (2024), 366 monitored days. EPA AQS → · NOAA →
Insights: Hartford-West Hartford-East Hartford, CT metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 40 over 366 measured days in 2024, which corresponds to a Good band and a Good metro-wide health grade. The monitored-day split lands at 276 Good days (75%), 81 Moderate (22%), and 8 Unhealthy-for-Sensitive-Groups (2%). The 90th-percentile AQI finished at 64 while the highest single-day reading hit 185 (Unhealthy). Metro residents averaged roughly 22.6 clean-air days per 30-day window across the reporting year.
Across the 2020–2024 trend window, good days shifted by +31 and the median AQI moved -3 points, which classifies the multi-year trajectory as improving. The metro recorded 1 unhealthy-or-worse days combined, on those days the EPA recommends that sensitive groups limit prolonged outdoor exertion, and many schools and athletic programs adjust outdoor activity accordingly. Metros with comparable AQI profiles include Bismarck, ND (73.0% good, AQI 40); Cambridge, MD (80.3% good, AQI 40); Charleston, WV (77.8% good, AQI 40).
Air Quality Summary
Median AQI
40
Good
Good Days
75.4%
276 of 366 days
Max AQI
185
Unhealthy
Health Grade
Good
90th pct: 64
AQI Day Breakdown (2024)
Distribution of 366 monitored days across EPA AQI categories.
Good
276
75%
Moderate
81
22%
USG
8
2%
Unhealthy
1
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Health Impact Assessment
The Hartford-West Hartford-East Hartford, CT metro area's air quality is rated Good based on 75.4% good air days. There were 1 unhealthy days in 2024 when outdoor activity should be limited.
Air quality is acceptable most days, but 8 days reached "Unhealthy for Sensitive Groups" and peak AQI reached 185. Sensitive groups should monitor real-time conditions at AirNow.gov.
How does the Hartford-West Hartford-East Hartford, CT metro compare?
How Hartford-West Hartford-East Hartford, CT compares
5-Year Air Quality Trend
Air quality is improving in the Hartford-West Hartford-East Hartford, CT metro. Best year: 2024 (276 good days).
| Year | Good | Moderate | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|
| 2020 | 245 | 119 | 0 | 43 | 129 |
| 2021 | 243 | 107 | 1 | 43 | 151 |
| 2022 | 251 | 107 | 0 | 43 | 147 |
| 2023 | 223 | 133 | 4 | 44 | 166 |
| 2024 | 276 | 81 | 1 | 40 | 185 |
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Frequently Asked Questions
What is the air quality in the Hartford-West Hartford-East Hartford, CT metro area? ▼
How many unhealthy air days does Hartford-West Hartford-East Hartford, CT have? ▼
Is air quality in Hartford-West Hartford-East Hartford, CT getting better or worse? ▼
What does AQI 40 mean for health? ▼
What is the 90th percentile AQI for Hartford-West Hartford-East Hartford, CT? ▼
How does Hartford-West Hartford-East Hartford, CT compare to other metro areas? ▼
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by CBSA dataset, 2020–2024. The AQS collects ambient air monitoring data from state, local, and tribal monitoring agencies across the United States.
Metrics: Air Quality Index (AQI) is calculated using EPA-standard breakpoints for six criteria pollutants: PM2.5, PM10, Ozone, NO2, CO, and SO2. Median AQI, max AQI, and 90th percentile AQI are computed from daily measurements. Good days percentage reflects days with AQI 0–50.
Coverage: 501 metro areas (Core Based Statistical Areas). Only metros with active monitoring stations are included. Unmonitored areas are not represented.
Read our methodology , how this data is sourced, computed, and verified.
Source: U.S. EPA, AirNow / AQS Air Quality Index readings and pollutant concentrations · 2025