* FoE's findings for Llangollen.
Traffic pollution levels in parts of Llangollen are comparable to those found in major cities, according to environmental champions.
In one location pollution is close to the legal limit, potentially putting at risk the health of residents, claims Friends of Earth's local group.
In January this year the group deployed five Nitrogen Dioxide measuring kits to measure this pollution for three weeks and they say the results were surprising.
The European Union has set a legal average annual limit for NO2 at 40µg/m3 (micrograms per cubic metre). But even at low levels, short term and long term exposure to NO2 can have significant negative health effects.
FoE says one of the measurement sites was found to be very close to the 40µg/m3 limit and that the levels displayed in Llangollen, especially those on the A539 Mill Street and by the A5/Castle Street traffic lights are comparable to those found in certain locations in major cities, such as Chester, the outskirts of Liverpool, Walsall and the dockland area of Cardiff.
* The table of results.
Group member Warren Davies said: "These readings were taken during January and February when the traffic is pretty quiet. If the rest of the year was taken into account, the average values could be much higher.
"There is a lot of talk about reducing emissions in London and in cities, but localised air pollution in our towns can be just as unhealthy.”
Nationally, outdoor air pollution is responsible for 40,000 premature deaths a year in the UK, according to the Royal College of Physicians (RCP) and Royal College of Paediatrics and Child Health.
NO2 is associated with vehicle traffic. Nationally Friends of the Earth is calling for restrictions of the dirtiest vehicles.
Locally, Llangollen & District Friends of the Earth are calling on local decision makers to consider their findings and to invest in schemes locally to reduce emissions by encouraging walking and cycling, and discouraging traffic-generating developments.