Stay updated with real-time air quality in Greenwich, 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)
29
Good
Greenwich, Connecticut
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
4.50 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
18.28 μg/m³
0
55
155
255
425
605+
31.20 ppb
0
55
71
86
201
201+
0.40 ppb
0
36
76
186
605
1005+
11.37 ppb
0
54
101
361
1250
2050+
0.27 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Greenwich, Connecticut
Greenwich, Connecticut
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AQI 44
Good
7.73μg/m³
PM2.5
34.34μg/m³
PM10
12.24ppb
O3
0.47ppb
SO2
20.36ppb
NO2
0.29ppm
CO
AQI 49
Good
8.92μg/m³
PM2.5
38.55μg/m³
PM10
9.76ppb
O3
0.58ppb
SO2
23.08ppb
NO2
0.30ppm
CO
AQI 49
Good
8.76μg/m³
PM2.5
29.75μg/m³
PM10
15.86ppb
O3
0.35ppb
SO2
23.36ppb
NO2
0.28ppm
CO
AQI 49
Good
8.91μg/m³
PM2.5
38.54μg/m³
PM10
9.52ppb
O3
0.58ppb
SO2
23.06ppb
NO2
0.30ppm
CO
AQI 49
Good
8.92μg/m³
PM2.5
39.05μg/m³
PM10
6.15ppb
O3
0.50ppb
SO2
22.84ppb
NO2
0.29ppm
CO
AQI 49
Good
8.92μg/m³
PM2.5
38.38μg/m³
PM10
10.51ppb
O3
0.60ppb
SO2
23.13ppb
NO2
0.30ppm
CO
Air quality data and pollutant measurements for Connecticut, USA adhere to strict US EPA standards. The data is collected from multiple reliable sources, including satellites and ground-based monitoring stations. This data is further analyzed and enhanced using machine learning and advanced algorithms that factor in elements such as traffic and population density, ensuring accurate and reliable results.
Source: Ambee Data Sources
The air quality for Greenwich, Connecticut is updated every hour.
The worst air quality in Greenwich, Connecticut in the last 24 hours was observed at 03:00:00 on 2025-11-03.
In the last 24 hrs, the best air quality in Greenwich, Connecticut was observed at 04:00:00 on 2025-11-02.
The current air quality in Greenwich, Connecticut is 54, categorized as Moderate based on real-time data.
The most common pollutant in Greenwich, Connecticut is PM2.5.
If the air quality in Greenwich, Connecticut is poor, consider staying indoors and wearing a mask to protect yourself.
The current PM2.5 concentration at Greenwich, Connecticut is 10.948 μg/m3.
The current PM10 concentration at Greenwich, Connecticut is 29.76 μg/m3.
The current carbon monoxide (CO) concentration at Greenwich, Connecticut is 0.31 ppm.
The current sulfur dioxide (SO2) concentration at Greenwich, Connecticut is 0.179 ppb.
The current ozone (O3) concentration at Greenwich, Connecticut is 14.907 ppm.
The current nitrogen dioxide (NO2) concentration at Greenwich, Connecticut is 21.073 ppb.
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