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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 2016

2015 2016

Nitrogen dioxide

Date NO2 Units
06/01/2016  6 ugm-3
03/02/2016  21 ugm-3
02/03/2016  26 ugm-3
30/03/2016  21 ugm-3
27/04/2016  25 ugm-3
25/05/2016  22 ugm-3
29/06/2016  18 ugm-3
27/07/2016  15 ugm-3
24/08/2016  14* ugm-3
28/09/2016  19* 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