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Due to the large number of diffusion tube sites in Scotland, this diffusion tube map has been design using a cluster system. This system groups multiple sites found in a specific area into one point with the number of sites within that area stated within the point. Once that point is selected or the user zooms in the cluster point ungroups showing individual sites or smaller clusters. Site data can be found within the individual site point.

Diffusive samplers (as described in paragraphs 7.179 - 7.199 of the Technical Guidance LAQM.TG(16) ) are widely used for indicative monitoring of ambient nitrogen dioxide (NO2) in the context of Review and Assessment.

Diffusion tubes are particularly useful:

  • When simple, indicative techniques will suffice;
  • To give an indication of longer-term average NO2 concentrations;
  • For highlighting areas of high NO2 concentration
  • Where installation of an automatic analyser is not feasible

They are useful for identifying areas of high NO2 concentration, particularly when dealing with sources such as traffic emissions, which do not change much from day to day.