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)
49
Good
Watford, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
8.62 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
22.48 μg/m³
0
55
155
255
425
605+
44.47 ppb
0
55
71
86
201
201+
0.65 ppb
0
36
76
186
605
1005+
20.39 ppb
0
54
101
361
1250
2050+
0.01 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Watford, Hertfordshire
Watford, Hertfordshire
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AQI 54
Moderate
11.15μg/m³
PM2.5
31.62μg/m³
PM10
51.05ppb
O3
0.64ppb
SO2
19.34ppb
NO2
0.00ppm
CO
AQI 44
Good
8.01μg/m³
PM2.5
27.63μg/m³
PM10
45.54ppb
O3
0.65ppb
SO2
12.69ppb
NO2
0.01ppm
CO
AQI 44
Good
7.70μg/m³
PM2.5
24.32μg/m³
PM10
45.54ppb
O3
0.65ppb
SO2
8.42ppb
NO2
0.01ppm
CO
AQI 44
Good
7.70μg/m³
PM2.5
24.32μg/m³
PM10
45.54ppb
O3
0.65ppb
SO2
8.42ppb
NO2
0.01ppm
CO
AQI 47
Good
8.03μg/m³
PM2.5
22.51μg/m³
PM10
50.59ppb
O3
0.64ppb
SO2
10.37ppb
NO2
0.00ppm
CO
AQI 52
Moderate
9.74μg/m³
PM2.5
27.64μg/m³
PM10
50.47ppb
O3
0.64ppb
SO2
17.52ppb
NO2
0.00ppm
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 09:00:00 on 2026-08-13.
The best air quality in Watford, Hertfordshire was recorded at 10:00:00 on 2026-08-13.
The real-time air quality index in Watford, Hertfordshire is 44, 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 7.548 μg/m3.
The current PM10 levels in Watford, Hertfordshire are 22.75 μg/m3.
The current carbon monoxide (CO) level in Watford, Hertfordshire is 0.004 ppm.
The current sulfur dioxide (SO2) levels in Watford, Hertfordshire are 0.646 ppb.
The current ozone (O3) levels at Watford, Hertfordshire is 44.699 ppm.
The current nitrogen dioxide (NO2) levels at Watford, Hertfordshire is 22.116 ppb.
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