AURN Monitoring Site Monitoring Data

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London Westminster (HORS, an AURN site)

Latitude: 51.494670
Longitude: -0.131931
Date Started: 17/07/2001
Altitude: 5 metres
Environment: Urban Background

Latest Data

This monitoring site data was last updated: 06/12/2025 04:00

Parameter Pollution Band Concentration Period
Ozone (O3) Low (Index 2) 63 µg/m3 8 Hour mean
Nitrogen dioxide (NO2) Low (Index 1) 7 µg/m3 hourly mean
PM2.5 particulate matter (Hourly measured)   No Data 24 Hour mean
Nitric oxide (NO) not applicable 0 µg/m3 hourly mean
Nitrogen oxides as nitrogen dioxide (NOx as NO2) not applicable 8 µg/m3 hourly mean

Note: Values are based on provisional data. Data are GMT hour ending.
PM10 is measured as a running 24 hour mean, up to the current hour, and the band/index is calculated accordingly.

Map showing the location of the London Westminster monitoring site