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Latest air quality summary

Number of monitoring sites in each pollution band

Heathrow Airwatch was last updated at 12:00 on Tuesday 28th September 2021

  • Low22
  • Moderate0
  • High0
  • Very High0
  • No Data3
  • 25

    Total monitoring sites

Green Low (1-3) Orange Moderate (4-6) Red High (7-9) Purple Very High (10)
Grey Offline | Find out more about the air pollution index and bandings

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London Hillingdon Harmondsworth Os

Maximum pollution level at this monitoring site is Index 1
Parameter Pollution Band Concentration Period
PM2.5 Particulate matter (PM2.5)
Updated: 28/09/2021 05:00 		Low (Index 1) 4 µg/m3 (Osiris) 24 Hour mean
PM10 Particulate matter (PM10)
Updated: 28/09/2021 05:00 		Low (Index 1) 10 µg/m3 (INDIC GRAV) 24 Hour mean

Note: These results are based on provisional data. The data are presented in graphical form based on the highest pollutant measured at each site.