Stay updated with real-time air quality in Watford, 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
Watford, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
7.13 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
9.87 μg/m³
0
55
155
255
425
605+
22.36 ppb
0
55
71
86
201
201+
0.90 ppb
0
36
76
186
605
1005+
5.83 ppb
0
54
101
361
1250
2050+
0.53 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Watford, Hertfordshire
Watford, Hertfordshire
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AQI 38
Good
7.50μg/m³
PM2.5
12.75μg/m³
PM10
26.74ppb
O3
1.01ppb
SO2
18.63ppb
NO2
0.63ppm
CO
AQI 54
Moderate
10.52μg/m³
PM2.5
15.40μg/m³
PM10
23.38ppb
O3
0.79ppb
SO2
7.72ppb
NO2
0.63ppm
CO
AQI 52
Moderate
10.37μg/m³
PM2.5
25.44μg/m³
PM10
21.17ppb
O3
0.81ppb
SO2
10.26ppb
NO2
0.63ppm
CO
AQI 52
Moderate
10.37μg/m³
PM2.5
25.44μg/m³
PM10
21.17ppb
O3
0.81ppb
SO2
10.26ppb
NO2
0.63ppm
CO
AQI 33
Good
6.01μg/m³
PM2.5
9.20μg/m³
PM10
24.68ppb
O3
0.87ppb
SO2
11.36ppb
NO2
0.63ppm
CO
AQI 38
Good
7.21μg/m³
PM2.5
13.69μg/m³
PM10
25.17ppb
O3
0.93ppb
SO2
15.30ppb
NO2
0.63ppm
CO
Air quality measurements for Hertfordshire, UK meet strict US EPA standards. These measurements are collected from reliable sources, including satellites and ground-based monitoring systems. Advanced algorithms and machine learning techniques are applied to the data, factoring in variables such as traffic and population density, to ensure precision and reliability.
Source: Ambee Data Sources
Air quality data for Watford, Hertfordshire is updated on an hourly basis.
The worst air quality in Watford, Hertfordshire was recorded at 02:00:00 on 2026-02-12.
The best air quality in Watford, Hertfordshire was recorded at 11:00:00 on 2026-02-11.
The real-time air quality index in Watford, Hertfordshire is 38, currently categorized as Good.
The most common pollutant in Watford, Hertfordshire is PM2.5.
If the air quality in Watford, Hertfordshire is poor, limit outdoor activities and use a mask to safeguard your health.
The measured PM2.5 levels in Watford, Hertfordshire at present are 7.129 μg/m3.
The current PM10 levels in Watford, Hertfordshire are 9.87 μg/m3.
The current carbon monoxide (CO) level in Watford, Hertfordshire is 0.531 ppm.
The current sulfur dioxide (SO2) levels in Watford, Hertfordshire are 0.902 ppb.
The current ozone (O3) levels at Watford, Hertfordshire is 22.357 ppm.
The current nitrogen dioxide (NO2) levels at Watford, Hertfordshire is 5.831 ppb.
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