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
6.58 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
12.00 μg/m³
0
55
155
255
425
605+
21.27 ppb
0
55
71
86
201
201+
0.67 ppb
0
36
76
186
605
1005+
15.00 ppb
0
54
101
361
1250
2050+
0.76 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Watford, Hertfordshire
Watford, Hertfordshire
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AQI 33
Good
6.14μg/m³
PM2.5
14.71μg/m³
PM10
22.25ppb
O3
0.72ppb
SO2
14.62ppb
NO2
0.76ppm
CO
AQI 44
Good
7.97μg/m³
PM2.5
35.69μg/m³
PM10
21.68ppb
O3
0.67ppb
SO2
13.11ppb
NO2
0.76ppm
CO
AQI 44
Good
7.93μg/m³
PM2.5
12.40μg/m³
PM10
20.12ppb
O3
0.67ppb
SO2
8.53ppb
NO2
0.76ppm
CO
AQI 44
Good
7.93μg/m³
PM2.5
12.40μg/m³
PM10
20.12ppb
O3
0.67ppb
SO2
8.53ppb
NO2
0.76ppm
CO
AQI 38
Good
7.15μg/m³
PM2.5
12.04μg/m³
PM10
20.65ppb
O3
0.67ppb
SO2
15.03ppb
NO2
0.76ppm
CO
AQI 38
Good
7.31μg/m³
PM2.5
21.07μg/m³
PM10
21.80ppb
O3
0.70ppb
SO2
16.91ppb
NO2
0.76ppm
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 07:00:00 on 2026-11-12.
The best air quality in Watford, Hertfordshire was recorded at 10:00:00 on 2026-11-12.
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 6.575 μg/m3.
The current PM10 levels in Watford, Hertfordshire are 12.001 μg/m3.
The current carbon monoxide (CO) level in Watford, Hertfordshire is 0.761 ppm.
The current sulfur dioxide (SO2) levels in Watford, Hertfordshire are 0.668 ppb.
The current ozone (O3) levels at Watford, Hertfordshire is 21.266 ppm.
The current nitrogen dioxide (NO2) levels at Watford, Hertfordshire is 14.998 ppb.
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