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Diffusion tube monitoring data

This page contains links to our data for our nitrogen dioxide passive diffusion tube monitoring.

The National Air Quality Objective for Nitrogen Dioxide is

  • annual average of 40ug/m3
  • or a 1 hour mean of 200ug/m3, not to be exceeded more than 18 times a year.

Please note this data may vary from that in our Annual Status Reports as in some instances no bias correction has been applied to the data. The bias correction is calculated every year through co-location studies. Each manufacturer of passive diffusion tubes locate their diffusion tubes on a few of the Government's Automatic Urban and Rural (AURN) monitoring sites. This is a national network of air quality monitoring sites covering the whole of the UK. Based on this study a correction factor is produced for each type of diffusion tube. We then use this co-efficient to correct our data based on the diffusion tubes we use.

Our tubes are Gradko 20% triethylamine (TEA) in water.

2022 Nitrogen dioxide diffusion tube data

2021 Diffusion tube monitoring data

2020 Nitrogen dioxide tube data

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