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)
27
Good
Watford, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
3.50 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
8.30 μg/m³
0
55
155
255
425
605+
28.77 ppb
0
55
71
86
201
201+
0.89 ppb
0
36
76
186
605
1005+
4.69 ppb
0
54
101
361
1250
2050+
0.11 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Watford, Hertfordshire
Watford, Hertfordshire
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AQI 26
Good
3.21μg/m³
PM2.5
7.53μg/m³
PM10
27.72ppb
O3
0.86ppb
SO2
2.58ppb
NO2
0.12ppm
CO
AQI 24
Good
3.57μg/m³
PM2.5
7.95μg/m³
PM10
26.46ppb
O3
0.94ppb
SO2
5.80ppb
NO2
0.12ppm
CO
AQI 24
Good
3.23μg/m³
PM2.5
14.22μg/m³
PM10
26.38ppb
O3
0.93ppb
SO2
7.51ppb
NO2
0.12ppm
CO
AQI 24
Good
3.23μg/m³
PM2.5
14.22μg/m³
PM10
26.38ppb
O3
0.93ppb
SO2
7.51ppb
NO2
0.12ppm
CO
AQI 26
Good
3.18μg/m³
PM2.5
5.75μg/m³
PM10
27.59ppb
O3
0.91ppb
SO2
2.15ppb
NO2
0.12ppm
CO
AQI 26
Good
3.78μg/m³
PM2.5
9.86μg/m³
PM10
27.52ppb
O3
0.89ppb
SO2
4.86ppb
NO2
0.12ppm
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 01:00:00 on 2026-05-13.
The best air quality in Watford, Hertfordshire was recorded at 08:00:00 on 2026-05-14.
The real-time air quality index in Watford, Hertfordshire is 27, currently categorized as Good.
The most common pollutant in Watford, Hertfordshire is O3.
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 3.495 μg/m3.
The current PM10 levels in Watford, Hertfordshire are 8.298 μg/m3.
The current carbon monoxide (CO) level in Watford, Hertfordshire is 0.108 ppm.
The current sulfur dioxide (SO2) levels in Watford, Hertfordshire are 0.887 ppb.
The current ozone (O3) levels at Watford, Hertfordshire is 28.77 ppm.
The current nitrogen dioxide (NO2) levels at Watford, Hertfordshire is 4.694 ppb.
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