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)
38
Good
Welwyn Garden City, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
7.44 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
15.66 μg/m³
0
55
155
255
425
605+
19.22 ppb
0
55
71
86
201
201+
0.86 ppb
0
36
76
186
605
1005+
14.34 ppb
0
54
101
361
1250
2050+
0.80 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Welwyn Garden City, Hertfordshire
Welwyn Garden City, Hertfordshire
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AQI 49
Good
9.17μg/m³
PM2.5
10.32μg/m³
PM10
23.77ppb
O3
0.93ppb
SO2
22.64ppb
NO2
1.01ppm
CO
AQI 49
Good
9.06μg/m³
PM2.5
21.94μg/m³
PM10
24.14ppb
O3
0.96ppb
SO2
22.60ppb
NO2
1.01ppm
CO
AQI 44
Good
8.49μg/m³
PM2.5
23.14μg/m³
PM10
26.93ppb
O3
0.95ppb
SO2
23.18ppb
NO2
1.01ppm
CO
AQI 33
Good
5.95μg/m³
PM2.5
18.99μg/m³
PM10
25.58ppb
O3
0.87ppb
SO2
21.68ppb
NO2
1.01ppm
CO
AQI 44
Good
8.13μg/m³
PM2.5
13.68μg/m³
PM10
19.33ppb
O3
0.95ppb
SO2
22.80ppb
NO2
1.01ppm
CO
AQI 44
Good
7.95μg/m³
PM2.5
17.05μg/m³
PM10
23.08ppb
O3
0.94ppb
SO2
17.82ppb
NO2
1.01ppm
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 12:00:00 on 2026-02-12.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 11:00:00 on 2026-02-11.
The current air quality in Welwyn Garden City, Hertfordshire is 38, 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 7.442 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 15.657 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.803 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 0.864 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 19.224 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 14.342 ppb.
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