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)
25
Good
Harpenden, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
3.12 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
18.24 μg/m³
0
55
155
255
425
605+
26.64 ppb
0
55
71
86
201
201+
0.34 ppb
0
36
76
186
605
1005+
7.63 ppb
0
54
101
361
1250
2050+
0.02 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Low
Harpenden, Hertfordshire
Harpenden, Hertfordshire
Scroll To Air Quality MapLoading...
AQI 26
Good
3.16μg/m³
PM2.5
12.24μg/m³
PM10
28.15ppb
O3
0.34ppb
SO2
7.41ppb
NO2
0.02ppm
CO
AQI 27
Good
4.43μg/m³
PM2.5
8.70μg/m³
PM10
29.03ppb
O3
0.34ppb
SO2
7.51ppb
NO2
0.02ppm
CO
AQI 26
Good
2.94μg/m³
PM2.5
9.45μg/m³
PM10
27.93ppb
O3
0.34ppb
SO2
2.44ppb
NO2
0.02ppm
CO
AQI 26
Good
3.23μg/m³
PM2.5
12.54μg/m³
PM10
28.26ppb
O3
0.34ppb
SO2
2.94ppb
NO2
0.01ppm
CO
AQI 27
Good
4.43μg/m³
PM2.5
8.70μg/m³
PM10
29.03ppb
O3
0.34ppb
SO2
7.51ppb
NO2
0.02ppm
CO
AQI 25
Good
2.95μg/m³
PM2.5
9.44μg/m³
PM10
26.61ppb
O3
0.34ppb
SO2
2.43ppb
NO2
0.03ppm
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 11:00:00 on 2025-12-27.
In the last 24 hours, the best air quality in Harpenden, Hertfordshire was observed at 12:00:00 on 2025-12-28.
As of now, the AQI in Harpenden, Hertfordshire is 26, indicating Good conditions.
Harpenden, Hertfordshire air has the highest levels of O3.
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 2.962 μg/m3.
The PM10 concentration in Harpenden, Hertfordshire is 9.468 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Harpenden, Hertfordshire is 0.021 ppm.
Currently, Harpenden, Hertfordshire has a sulfur dioxide (SO2) concentration of 0.261 ppb.
The current ozone (O3) level in Harpenden, Hertfordshire at the moment is 27.757 ppm.
Nitrogen dioxide (NO2) level in Harpenden, Hertfordshire at the moment is 7.48 ppb.
All Rights Reserved © Ambee Inc. 2025