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)
52
Moderate
Harpenden, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
9.74 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
36.45 μg/m³
0
55
155
255
425
605+
23.12 ppb
0
55
71
86
201
201+
0.91 ppb
0
36
76
186
605
1005+
7.69 ppb
0
54
101
361
1250
2050+
0.01 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Harpenden, Hertfordshire
Harpenden, Hertfordshire
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AQI 49
Good
8.84μg/m³
PM2.5
17.90μg/m³
PM10
19.72ppb
O3
0.84ppb
SO2
16.98ppb
NO2
0.01ppm
CO
AQI 44
Good
8.28μg/m³
PM2.5
19.05μg/m³
PM10
16.99ppb
O3
0.91ppb
SO2
11.26ppb
NO2
0.01ppm
CO
AQI 38
Good
6.92μg/m³
PM2.5
29.81μg/m³
PM10
16.68ppb
O3
0.91ppb
SO2
6.37ppb
NO2
0.01ppm
CO
AQI 52
Moderate
9.98μg/m³
PM2.5
20.90μg/m³
PM10
21.49ppb
O3
0.92ppb
SO2
13.38ppb
NO2
0.01ppm
CO
AQI 44
Good
8.28μg/m³
PM2.5
19.05μg/m³
PM10
16.99ppb
O3
0.91ppb
SO2
11.26ppb
NO2
0.01ppm
CO
AQI 54
Moderate
10.73μg/m³
PM2.5
45.58μg/m³
PM10
16.83ppb
O3
0.90ppb
SO2
23.13ppb
NO2
0.01ppm
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 01:00:00 on 2026-02-10.
In the last 24 hours, the best air quality in Harpenden, Hertfordshire was observed at 05:00:00 on 2026-02-10.
As of now, the AQI in Harpenden, Hertfordshire is 52, indicating Moderate 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 9.742 μg/m3.
The PM10 concentration in Harpenden, Hertfordshire is 36.447 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Harpenden, Hertfordshire is 0.014 ppm.
Currently, Harpenden, Hertfordshire has a sulfur dioxide (SO2) concentration of 0.907 ppb.
The current ozone (O3) level in Harpenden, Hertfordshire at the moment is 23.118 ppm.
Nitrogen dioxide (NO2) level in Harpenden, Hertfordshire at the moment is 7.691 ppb.
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