Stay updated with real-time air quality in Welwyn Garden City, Hertfordshire 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)
26
Good
Welwyn Garden City, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
2.94 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
9.45 μg/m³
0
55
155
255
425
605+
27.93 ppb
0
55
71
86
201
201+
0.34 ppb
0
36
76
186
605
1005+
2.44 ppb
0
54
101
361
1250
2050+
0.02 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Welwyn Garden City, Hertfordshire
Welwyn Garden City, Hertfordshire
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AQI 26
Good
3.23μg/m³
PM2.5
12.54μg/m³
PM10
28.26ppb
O3
0.34ppb
SO2
2.94ppb
NO2
0.01ppm
CO
AQI 27
Good
2.90μg/m³
PM2.5
11.47μg/m³
PM10
29.43ppb
O3
0.18ppb
SO2
2.92ppb
NO2
0.01ppm
CO
AQI 26
Good
2.96μg/m³
PM2.5
9.47μg/m³
PM10
27.76ppb
O3
0.26ppb
SO2
7.48ppb
NO2
0.02ppm
CO
AQI 26
Good
3.16μg/m³
PM2.5
12.24μg/m³
PM10
28.15ppb
O3
0.34ppb
SO2
7.41ppb
NO2
0.02ppm
CO
AQI 26
Good
2.94μg/m³
PM2.5
18.24μg/m³
PM10
27.65ppb
O3
0.34ppb
SO2
2.65ppb
NO2
0.02ppm
CO
AQI 28
Good
3.70μg/m³
PM2.5
7.11μg/m³
PM10
30.46ppb
O3
0.39ppb
SO2
13.99ppb
NO2
0.01ppm
CO
Air quality data and pollutant measurements for Hertfordshire, UK 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 Welwyn Garden City, Hertfordshire is updated every hour.
The worst air quality in Welwyn Garden City, Hertfordshire in the last 24 hours was observed at 11:00:00 on 2025-12-27.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 12:00:00 on 2025-12-28.
The current air quality in Welwyn Garden City, Hertfordshire is 26, categorized as Good based on real-time data.
The most common pollutant in Welwyn Garden City, Hertfordshire is O3.
If the air quality in Welwyn Garden City, Hertfordshire is poor, consider staying indoors and wearing a mask to protect yourself.
The current PM2.5 concentration at Welwyn Garden City, Hertfordshire is 2.942 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 9.451 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.019 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 0.339 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 27.933 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 2.439 ppb.
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