Local bias adjustment factors

Many Local Authorities are now carrying out diffusion tube co-location studies. A spreadsheet has been developed to assist diffusion tube users in calculating the precision and accuracy of their results, in co-location studies where diffusion tubes are compared with automatic analysers. It can be used to calculate a bias adjustment factor (with a 95% confidence interval as an estimate of the uncertainty on the bias adjustment factor), and then to apply the bias adjustment factor to annual mean results from other NO2 diffusion tube sites. Download a copy of this spreadsheet (XLS 1.5Mb).

Please ensure that the tubes are located and used in accordance with current guidance.