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)
30
Good
Greenwich, Connecticut
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
2.75 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
11.88 μg/m³
0
55
155
255
425
605+
31.87 ppb
0
55
71
86
201
201+
0.60 ppb
0
36
76
186
605
1005+
3.19 ppb
0
54
101
361
1250
2050+
0.32 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Greenwich, Connecticut
Greenwich, Connecticut
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AQI 28
Good
1.77μg/m³
PM2.5
7.16μg/m³
PM10
29.73ppb
O3
0.34ppb
SO2
2.42ppb
NO2
0.32ppm
CO
AQI 24
Good
1.89μg/m³
PM2.5
7.71μg/m³
PM10
25.77ppb
O3
0.35ppb
SO2
2.75ppb
NO2
0.32ppm
CO
AQI 29
Good
1.74μg/m³
PM2.5
6.77μg/m³
PM10
31.47ppb
O3
0.34ppb
SO2
2.36ppb
NO2
0.32ppm
CO
AQI 22
Good
1.94μg/m³
PM2.5
7.95μg/m³
PM10
23.99ppb
O3
0.35ppb
SO2
2.84ppb
NO2
0.32ppm
CO
AQI 19
Good
1.79μg/m³
PM2.5
7.49μg/m³
PM10
20.21ppb
O3
0.35ppb
SO2
2.09ppb
NO2
0.32ppm
CO
AQI 22
Good
2.02μg/m³
PM2.5
8.26μg/m³
PM10
23.82ppb
O3
0.36ppb
SO2
3.14ppb
NO2
0.32ppm
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 11:00:00 on 2026-09-12.
In the last 24 hrs, the best air quality in Greenwich, Connecticut was observed at 03:00:00 on 2026-09-13.
The current air quality in Greenwich, Connecticut is 30, categorized as Good based on real-time data.
The most common pollutant in Greenwich, Connecticut is O3.
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 2.748 μg/m3.
The current PM10 concentration at Greenwich, Connecticut is 11.876 μg/m3.
The current carbon monoxide (CO) concentration at Greenwich, Connecticut is 0.318 ppm.
The current sulfur dioxide (SO2) concentration at Greenwich, Connecticut is 0.597 ppb.
The current ozone (O3) concentration at Greenwich, Connecticut is 31.871 ppm.
The current nitrogen dioxide (NO2) concentration at Greenwich, Connecticut is 3.188 ppb.
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