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)
29
Good
Harpenden, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
5.39 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
12.93 μg/m³
0
55
155
255
425
605+
31.26 ppb
0
55
71
86
201
201+
0.40 ppb
0
36
76
186
605
1005+
4.53 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 30
Good
5.44μg/m³
PM2.5
11.00μg/m³
PM10
32.12ppb
O3
0.38ppb
SO2
5.74ppb
NO2
0.01ppm
CO
AQI 32
Good
5.06μg/m³
PM2.5
12.53μg/m³
PM10
34.84ppb
O3
0.40ppb
SO2
3.27ppb
NO2
0.01ppm
CO
AQI 32
Good
5.15μg/m³
PM2.5
17.91μg/m³
PM10
34.59ppb
O3
0.40ppb
SO2
2.57ppb
NO2
0.01ppm
CO
AQI 32
Good
4.16μg/m³
PM2.5
17.85μg/m³
PM10
35.00ppb
O3
0.40ppb
SO2
3.62ppb
NO2
0.01ppm
CO
AQI 32
Good
5.06μg/m³
PM2.5
12.53μg/m³
PM10
34.84ppb
O3
0.40ppb
SO2
3.27ppb
NO2
0.01ppm
CO
AQI 30
Good
4.16μg/m³
PM2.5
17.27μg/m³
PM10
32.34ppb
O3
0.40ppb
SO2
2.23ppb
NO2
0.02ppm
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 2026-03-29.
In the last 24 hours, the best air quality in Harpenden, Hertfordshire was observed at 09:00:00 on 2026-03-29.
As of now, the AQI in Harpenden, Hertfordshire is 29, 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 5.394 μg/m3.
The PM10 concentration in Harpenden, Hertfordshire is 12.926 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Harpenden, Hertfordshire is 0.015 ppm.
Currently, Harpenden, Hertfordshire has a sulfur dioxide (SO2) concentration of 0.4 ppb.
The current ozone (O3) level in Harpenden, Hertfordshire at the moment is 31.261 ppm.
Nitrogen dioxide (NO2) level in Harpenden, Hertfordshire at the moment is 4.526 ppb.
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