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This section of the website allows you to choose a type of monitoring site, and then details for individual sites. Once you have chosen a site, its location will appear on the map above.

Choose a different type of monitoring site:
Hydocarbon Diffusion Tube sitesHydocarbon Diffusion Tube sites (8 Sites)
NO2 Diffusion Tube sitesNO2 Diffusion Tube sites (1010 Sites)
O3 Diffusion Tube sitesO3 Diffusion Tube sites (6 Sites)
SO2 Diffusion Tube sitesSO2 Diffusion Tube sites (9 Sites)

Non-Automatic Monitoring Sites in Wales

NO2 Diffusion Tube sites
in 2015


Nitrogen dioxide

Date NO2 Units
04/02/2015  65 ugm-3
04/03/2015  60 ugm-3
01/04/2015  53 ugm-3
29/04/2015  58 ugm-3
27/05/2015  40 ugm-3
01/07/2015  38 ugm-3
29/07/2015  39 ugm-3
26/08/2015  43 ugm-3
30/09/2015  46 ugm-3
28/10/2015  59 ugm-3

Ratification Status:
» Red* - Provisional
» Green - Ratified

Further data and graphs may be downloaded here.

For more information on this monitoring data please contact this local authority at