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)
26
Good
Harpenden, Hertfordshire
Last updated: ... (Local time)

Good
Fine
Moderate
Poor
Very poor
Hazardous
4.25 μg/m³
0
12.1
35.5
55.5
250.5
500.5+
7.99 μg/m³
0
55
155
255
425
605+
28.32 ppb
0
55
71
86
201
201+
0.90 ppb
0
36
76
186
605
1005+
5.46 ppb
0
54
101
361
1250
2050+
0.11 ppm
0
4.5
9.5
12.5
230.5
50.5+
Pollen Level
Moderate
Harpenden, Hertfordshire
Harpenden, Hertfordshire
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AQI 26
Good
3.78μg/m³
PM2.5
9.86μg/m³
PM10
27.52ppb
O3
0.89ppb
SO2
4.86ppb
NO2
0.12ppm
CO
AQI 24
Good
3.57μg/m³
PM2.5
7.95μg/m³
PM10
26.46ppb
O3
0.94ppb
SO2
5.80ppb
NO2
0.12ppm
CO
AQI 25
Good
4.31μg/m³
PM2.5
14.62μg/m³
PM10
26.96ppb
O3
0.95ppb
SO2
5.71ppb
NO2
0.12ppm
CO
AQI 24
Good
4.13μg/m³
PM2.5
5.63μg/m³
PM10
26.44ppb
O3
0.94ppb
SO2
7.23ppb
NO2
0.12ppm
CO
AQI 24
Good
3.57μg/m³
PM2.5
7.95μg/m³
PM10
26.46ppb
O3
0.94ppb
SO2
5.80ppb
NO2
0.12ppm
CO
AQI 25
Good
3.93μg/m³
PM2.5
17.12μg/m³
PM10
26.53ppb
O3
0.94ppb
SO2
9.95ppb
NO2
0.12ppm
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 05:00:00 on 2026-05-13.
In the last 24 hours, the best air quality in Harpenden, Hertfordshire was observed at 08:00:00 on 2026-05-14.
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 4.245 μg/m3.
The PM10 concentration in Harpenden, Hertfordshire is 7.994 μg/m3 at the moment.
The current carbon monoxide (CO) concentration in Harpenden, Hertfordshire is 0.108 ppm.
Currently, Harpenden, Hertfordshire has a sulfur dioxide (SO2) concentration of 0.899 ppb.
The current ozone (O3) level in Harpenden, Hertfordshire at the moment is 28.319 ppm.
Nitrogen dioxide (NO2) level in Harpenden, Hertfordshire at the moment is 5.46 ppb.
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