Heathrow Airwatch uses cookies to make the site simpler. Find out more about this

Latest air quality summary

Number of monitoring sites in each pollution band

Heathrow Airwatch was last updated at 04:00 on Thursday 23rd January 2020

  • Low21
  • Moderate2
  • High0
  • Very High0
  • No Data4
  • 27

    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

« Return to site summary list

Hounslow 4 - Chiswick High Road

Maximum pollution level at this monitoring site is Index 3
Parameter Pollution Band Concentration Period
PM2.5 Particulate matter (PM2.5)
Updated: 21/01/2020 08:00
  No Data 24 Hour mean
PM10 Particulate matter (PM10)
Updated: 23/01/2020 02:00
Low (Index 3) 35 µg/m3 (VCM) 24 Hour mean
Oxides of Nitrogen (NOXasNO2)
Updated: 23/01/2020 01:00
not applicable 66 µg/m3 hourly mean
Nitrogen dioxide (NO2)
Updated: 23/01/2020 01:00
Low (Index 1) 48 µg/m3 hourly mean
Nitric Oxide (NO)
Updated: 23/01/2020 01:00
not applicable 12 µg/m3 hourly 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.