Middlesex, Connecticut Air Quality
Middlesex County, Connecticut (CT)
→ 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 | 43 | 64 | 140 | 170 | 35 | 4 | Ozone |
| 2022 | 40 | 67 | 147 | 173 | 33 | 6 | Ozone |
| 2021 | 39 | 80 | 151 | 171 | 25 | 11 | Ozone |
| 2020 | 39 | 54 | 129 | 182 | 24 | 2 | Ozone |
| 2019 | 41 | 61 | 154 | 175 | 23 | 7 | Ozone |
| 2018 | 40 | 67 | 126 | 168 | 32 | 8 | Ozone |
| 2017 | 40 | 61 | 151 | 171 | 28 | 8 | Ozone |
| 2016 | 44 | 97 | 187 | 125 | 36 | 13 | Ozone |
| 2015 | 43 | 90 | 147 | 134 | 37 | 12 | Ozone |
| 2014 | 43 | 80 | 151 | 140 | 31 | 11 | Ozone |
What This Means for Middlesex County Residents
Middlesex, Connecticut has received an Air Quality Grade of B (65/100) based on a decade of monitoring data from the EPA's air quality monitoring program. The current median AQI of 43 falls in the "Good" range.
The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 6 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.
Frequently Asked Questions
Middlesex, Connecticut has a current median AQI of 43, which falls in the "Good" range. The area has received an Air Quality Grade of B (65/100) based on 10 years of EPA monitoring data.
Air quality in Middlesex, Connecticut is stable over the past decade. The median AQI has changed by 0 points from 2014 to 2023.
Middlesex, Connecticut averages 6 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 Middlesex, Connecticut is Ground-Level Ozone. This is the dominant contributor to elevated AQI readings in the Middlesex County area.
Middlesex, Connecticut averages 6 unhealthy air days per year. Asthma patients should monitor daily AQI readings and limit outdoor activity when AQI exceeds 100. The primary pollutant is Ground-Level Ozone, which is a known asthma trigger.
With a median AQI of 43 (Good), outdoor exercise in Middlesex, Connecticut is generally safe year-round. Middlesex, Connecticut averages 6 days per year when athletes should move workouts indoors.