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
6.66 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
21.75 μg/m³
0
55
155
255
425
605+
33.24 ppb
0
55
71
86
201
201+
0.48 ppb
0
36
76
186
605
1005+
2.59 ppb
0
54
101
361
1250
2050+
0.12 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 38
Good
6.60μg/m³
PM2.5
15.40μg/m³
PM10
34.88ppb
O3
0.46ppb
SO2
2.36ppb
NO2
0.12ppm
CO
AQI 33
Good
5.70μg/m³
PM2.5
19.68μg/m³
PM10
34.76ppb
O3
0.49ppb
SO2
2.38ppb
NO2
0.12ppm
CO
AQI 38
Good
6.67μg/m³
PM2.5
24.17μg/m³
PM10
33.18ppb
O3
0.48ppb
SO2
2.86ppb
NO2
0.12ppm
CO
AQI 33
Good
6.19μg/m³
PM2.5
18.80μg/m³
PM10
33.74ppb
O3
0.43ppb
SO2
1.50ppb
NO2
0.12ppm
CO
AQI 38
Good
6.68μg/m³
PM2.5
22.76μg/m³
PM10
35.37ppb
O3
0.50ppb
SO2
2.65ppb
NO2
0.12ppm
CO
AQI 38
Good
6.84μg/m³
PM2.5
16.59μg/m³
PM10
33.35ppb
O3
0.43ppb
SO2
2.17ppb
NO2
0.12ppm
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 05:00:00 on 2026-07-13.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 11:00:00 on 2026-07-12.
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 6.661 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 21.747 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.118 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 0.484 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 33.239 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 2.59 ppb.
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