Stay updated with real-time air quality in Colchester, Connecticut featuring accurate data on AQI, PM2.5, PM10, O3, NO2, SO2, and CO levels. Use our interactive map and detailed forecasts to monitor pollution trends, manage health risks, and plan your daily activities with confidence.
Live AQI (Air Quality Index)
33
Good
Colchester, Connecticut
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
5.51 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
15.54 μg/m³
0
55
155
255
425
605+
26.94 ppb
0
55
71
86
201
201+
0.18 ppb
0
36
76
186
605
1005+
4.38 ppb
0
54
101
361
1250
2050+
0.21 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Colchester, Connecticut
Colchester, Connecticut
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AQI 33
Good
6.08μg/m³
PM2.5
15.05μg/m³
PM10
28.70ppb
O3
0.34ppb
SO2
4.50ppb
NO2
0.21ppm
CO
AQI 33
Good
5.93μg/m³
PM2.5
13.10μg/m³
PM10
27.37ppb
O3
0.33ppb
SO2
5.44ppb
NO2
0.22ppm
CO
AQI 27
Good
4.57μg/m³
PM2.5
16.14μg/m³
PM10
23.02ppb
O3
0.32ppb
SO2
3.56ppb
NO2
0.22ppm
CO
AQI 38
Good
7.12μg/m³
PM2.5
16.67μg/m³
PM10
25.33ppb
O3
0.46ppb
SO2
5.11ppb
NO2
0.21ppm
CO
AQI 27
Good
4.82μg/m³
PM2.5
16.20μg/m³
PM10
22.77ppb
O3
0.32ppb
SO2
5.81ppb
NO2
0.23ppm
CO
AQI 33
Good
5.82μg/m³
PM2.5
16.54μg/m³
PM10
26.49ppb
O3
0.32ppb
SO2
3.82ppb
NO2
0.22ppm
CO
Air quality measurements for Connecticut, USA meet strict US EPA standards. These measurements are collected from reliable sources, including satellites and ground-based monitoring systems. Advanced algorithms and machine learning techniques are applied to the data, factoring in variables such as traffic and population density, to ensure precision and reliability.
Source: Ambee Data Sources
Air quality data for Colchester, Connecticut is updated on an hourly basis.
The worst air quality in Colchester, Connecticut was recorded at 03:00:00 on 2026-08-14.
The best air quality in Colchester, Connecticut was recorded at 04:00:00 on 2026-08-14.
The real-time air quality index in Colchester, Connecticut is 33, currently categorized as Good.
The most common pollutant in Colchester, Connecticut is PM2.5.
If the air quality in Colchester, Connecticut is poor, limit outdoor activities and use a mask to safeguard your health.
The measured PM2.5 levels in Colchester, Connecticut at present are 5.507 μg/m3.
The current PM10 levels in Colchester, Connecticut are 15.54 μg/m3.
The current carbon monoxide (CO) level in Colchester, Connecticut is 0.213 ppm.
The current sulfur dioxide (SO2) levels in Colchester, Connecticut are 0.179 ppb.
The current ozone (O3) levels at Colchester, Connecticut is 26.941 ppm.
The current nitrogen dioxide (NO2) levels at Colchester, Connecticut is 4.385 ppb.
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