Our environment

Air quality monitoring

Air quality monitoring is undertaken across the borough, the data collected is used to assess and improve air quality within the borough.

We monitor a number of pollutants. These are:

  • nitrogen dioxide (NO2) 
  • sulphur dioxide (SO2)
  • particulates (PM10)
  • benzene

and assess in regular reviews:

  • ozone
  • carbon dioxide

There are two techniques used to monitor air quality:

Diffusion tubes located around the borough sampling for Nitrogen Dioxide and Benzene.  These use a passive method, which means they do not use a pump to pull air through the sampler, instead air 'diffuses' into the sampler over the sampling period. The tubes are then collected and sent to a laboratory for analysis.  Diffusion tubes are a simple way of monitoring air pollution and allow a greater number of sites to be monitored.

Automatic monitoring stations consist of a permanent housing, such as a portacabin, which contains a number of sophisticated electronic instruments. Air is continuously pumped into each analyser, these report concentrations of Nitrogen Dioxide, Sulphur Dioxide and PM10 particulate matter automatically every hour. Automatic monitors are especially useful for providing near real-time public information and used to warn if air pollution is currently high.

Harrow has two automatic monitoring stations:

Harrow 1 is located in Stanmore - background - (Lat N51:37:03 Long W0:17:48, OS co-ordinates X 518033 : Y 192328, Land Ranger series TQ 180923).

Harrow 1 monitoring station

Harrow 2 is located next to Pinner Road, North Harrow -roadside - (Lat N51:35:13 Long W0:21:45, OS co-ordinates X 513543 : Y 188836, Land Ranger series TQ135888).

Harrow 2 monitoring station

Air quality monitoring data from both automatic and non-automatic methods is an important element of the air quality review and assessment process and provides a basis on which it is regularly appraised and taken forward. The action plan can be seen at: HarrowAir Quality Action Plan.

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