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

Good
Fine
Moderate
Poor
Very poor
Hazardous
7.36 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
17.14 μg/m³
0
55
155
255
425
605+
20.29 ppb
0
55
71
86
201
201+
0.86 ppb
0
36
76
186
605
1005+
14.69 ppb
0
54
101
361
1250
2050+
0.80 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Harpenden, Hertfordshire
Harpenden, Hertfordshire
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AQI 33
Good
5.95μg/m³
PM2.5
18.99μg/m³
PM10
25.58ppb
O3
0.87ppb
SO2
21.68ppb
NO2
1.01ppm
CO
AQI 52
Moderate
9.64μg/m³
PM2.5
26.22μg/m³
PM10
28.82ppb
O3
0.94ppb
SO2
25.99ppb
NO2
1.01ppm
CO
AQI 49
Good
9.48μg/m³
PM2.5
22.30μg/m³
PM10
27.28ppb
O3
0.95ppb
SO2
22.27ppb
NO2
1.01ppm
CO
AQI 49
Good
9.17μg/m³
PM2.5
10.32μg/m³
PM10
23.77ppb
O3
0.93ppb
SO2
22.64ppb
NO2
1.01ppm
CO
AQI 52
Moderate
9.64μg/m³
PM2.5
26.22μg/m³
PM10
28.82ppb
O3
0.94ppb
SO2
25.99ppb
NO2
1.01ppm
CO
AQI 33
Good
5.97μg/m³
PM2.5
25.67μg/m³
PM10
27.16ppb
O3
0.94ppb
SO2
30.32ppb
NO2
1.01ppm
CO
Air quality and pollutant data for Hertfordshire, UK are sourced from ground-based monitors and satellites, adhering to US EPA standards. Machine learning and advanced algorithms enhance the data by incorporating local variables like traffic and population density, ensuring high accuracy and dependability.
Source: Ambee Data Sources
The air quality information for Harpenden, Hertfordshire is updated every hour for accuracy.
In the past 24 hours, the air quality in Harpenden, Hertfordshire was at its worst at 12:00:00 on 2026-02-12.
In the last 24 hours, the best air quality in Harpenden, Hertfordshire was observed at 02:00:00 on 2026-02-11.
As of now, the AQI in Harpenden, Hertfordshire is 38, indicating Good conditions.
Harpenden, Hertfordshire air has the highest levels of PM2.5.
Poor air quality in Harpenden, Hertfordshire means it's advisable to stay indoors and wear a mask for your protection.
PM2.5 levels in Harpenden, Hertfordshire are currently 7.362 μg/m3.
The PM10 concentration in Harpenden, Hertfordshire is 17.143 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Harpenden, Hertfordshire is 0.803 ppm.
Currently, Harpenden, Hertfordshire has a sulfur dioxide (SO2) concentration of 0.864 ppb.
The current ozone (O3) level in Harpenden, Hertfordshire at the moment is 20.289 ppm.
Nitrogen dioxide (NO2) level in Harpenden, Hertfordshire at the moment is 14.686 ppb.
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