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)
30
Good
Welwyn Garden City, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
4.76 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
19.20 μg/m³
0
55
155
255
425
605+
32.35 ppb
0
55
71
86
201
201+
0.33 ppb
0
36
76
186
605
1005+
3.09 ppb
0
54
101
361
1250
2050+
0.01 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
High
Welwyn Garden City, Hertfordshire
Welwyn Garden City, Hertfordshire
Scroll To Air Quality MapLoading...
AQI 32
Good
4.16μg/m³
PM2.5
17.85μg/m³
PM10
35.00ppb
O3
0.40ppb
SO2
3.62ppb
NO2
0.01ppm
CO
AQI 34
Good
4.68μg/m³
PM2.5
19.29μg/m³
PM10
36.73ppb
O3
0.41ppb
SO2
3.53ppb
NO2
0.01ppm
CO
AQI 29
Good
5.39μg/m³
PM2.5
12.93μg/m³
PM10
31.26ppb
O3
0.40ppb
SO2
4.53ppb
NO2
0.01ppm
CO
AQI 30
Good
5.44μg/m³
PM2.5
11.00μg/m³
PM10
32.12ppb
O3
0.38ppb
SO2
5.74ppb
NO2
0.01ppm
CO
AQI 32
Good
5.13μg/m³
PM2.5
12.41μg/m³
PM10
34.63ppb
O3
0.40ppb
SO2
2.84ppb
NO2
0.02ppm
CO
AQI 31
Good
4.81μg/m³
PM2.5
8.99μg/m³
PM10
33.17ppb
O3
0.42ppb
SO2
5.58ppb
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 2026-03-28.
In the last 24 hrs, the best air quality in Welwyn Garden City, Hertfordshire was observed at 11:00:00 on 2026-03-29.
The current air quality in Welwyn Garden City, Hertfordshire is 32, 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 5.147 μg/m3.
The current PM10 concentration at Welwyn Garden City, Hertfordshire is 17.911 μg/m3.
The current carbon monoxide (CO) concentration at Welwyn Garden City, Hertfordshire is 0.014 ppm.
The current sulfur dioxide (SO2) concentration at Welwyn Garden City, Hertfordshire is 0.401 ppb.
The current ozone (O3) concentration at Welwyn Garden City, Hertfordshire is 34.589 ppm.
The current nitrogen dioxide (NO2) concentration at Welwyn Garden City, Hertfordshire is 2.566 ppb.
All Rights Reserved © Ambee Inc. 2025