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Twynrodyn Hill Twynrodyn Hill

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 (988 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

Twynrodyn Hill

NO2 Diffusion Tube sites
Twynrodyn Hill in 2012

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Nitrogen dioxide

Date NO2 Units
06/01/2012  79 ugm-3
09/02/2012  24 ugm-3
29/02/2012  69 ugm-3
30/03/2012  69 ugm-3
25/04/2012  47* ugm-3

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

Use the buttons above to view data for years between 2002 and 2012

Further data and graphs may be downloaded here.

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