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)
44
Good
Welwyn Garden City, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
7.93 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
15.99 μg/m³
0
55
155
255
425
605+
5.49 ppb
0
55
71
86
201
201+
0.76 ppb
0
36
76
186
605
1005+
17.76 ppb
0
54
101
361
1250
2050+
0.28 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
High
Welwyn Garden City, Hertfordshire
Welwyn Garden City, Hertfordshire
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AQI 49
Good
9.41μg/m³
PM2.5
15.62μg/m³
PM10
6.46ppb
O3
0.68ppb
SO2
20.82ppb
NO2
0.28ppm
CO
AQI 49
Good
9.09μg/m³
PM2.5
15.97μg/m³
PM10
9.85ppb
O3
0.52ppb
SO2
18.23ppb
NO2
0.28ppm
CO
AQI 27
Good
5.09μg/m³
PM2.5
14.34μg/m³
PM10
6.62ppb
O3
0.68ppb
SO2
23.73ppb
NO2
0.28ppm
CO
AQI 38
Good
6.95μg/m³
PM2.5
16.36μg/m³
PM10
6.04ppb
O3
0.72ppb
SO2
17.05ppb
NO2
0.28ppm
CO
AQI 27
Good
4.83μg/m³
PM2.5
17.84μg/m³
PM10
4.24ppb
O3
0.68ppb
SO2
15.77ppb
NO2
0.28ppm
CO
AQI 49
Good
8.60μg/m³
PM2.5
16.82μg/m³
PM10
5.33ppb
O3
0.72ppb
SO2
19.34ppb
NO2
0.28ppm
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 02:00:00 on 2026-10-07.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 08:00:00 on 2026-10-06.
The current air quality in Welwyn Garden City, Hertfordshire is 27, categorized as Good based on real-time data.
The most common pollutant in Welwyn Garden City, Hertfordshire is PM2.5.
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 5.372 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 17.5 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.285 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 0.675 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 3.92 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 15.968 ppb.
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