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)
23
Good
Welwyn Garden City, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
1.40 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
5.67 μg/m³
0
55
155
255
425
605+
25.43 ppb
0
55
71
86
201
201+
1.84 ppb
0
36
76
186
605
1005+
2.74 ppb
0
54
101
361
1250
2050+
0.02 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 22
Good
3.80μg/m³
PM2.5
18.08μg/m³
PM10
22.57ppb
O3
1.32ppb
SO2
4.17ppb
NO2
0.30ppm
CO
AQI 33
Good
6.42μg/m³
PM2.5
11.93μg/m³
PM10
19.60ppb
O3
1.48ppb
SO2
4.63ppb
NO2
0.30ppm
CO
AQI 32
Good
5.33μg/m³
PM2.5
35.30μg/m³
PM10
21.62ppb
O3
1.53ppb
SO2
4.74ppb
NO2
0.30ppm
CO
AQI 33
Good
6.01μg/m³
PM2.5
14.77μg/m³
PM10
21.82ppb
O3
0.89ppb
SO2
9.11ppb
NO2
0.30ppm
CO
AQI 38
Good
7.05μg/m³
PM2.5
32.40μg/m³
PM10
21.84ppb
O3
1.79ppb
SO2
4.47ppb
NO2
0.30ppm
CO
AQI 38
Good
7.27μg/m³
PM2.5
13.14μg/m³
PM10
19.24ppb
O3
0.96ppb
SO2
7.98ppb
NO2
0.30ppm
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 07:00:00 on 2025-11-07.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 03:00:00 on 2025-11-08.
The current air quality in Welwyn Garden City, Hertfordshire is 33, 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 5.64 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 29.231 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.296 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 1.58 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 21.898 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 3.949 ppb.
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