An environmental campaign group has warned south Bucks to not be “complacent” about pollution levels on a busy High Wycombe road – despite figures falling under the national limit.

A number of congested areas in Wycombe and Marlow – including Chapel Street - are either close to or exceed the national limit of 40 micrograms of nitrogen dioxide per cubic metre and action needs to be taken to address the issue, according to Wycombe Friends of the Earth.

In 2015 the yearly average of nitrogen dioxide levels in the London Road was 38.1 micrograms/m3, compared with 40.1 in 2011 – showing a drop of two micrograms/m3.

However the campaign group says these figures "are not levels that one should be complacent about" as they do not taken into account other traffic pollutants.

A representative said: “A Report produced last year by the Royal College of Physicians and Royal College of Paediatrics and Child Health titled “Every Breath We Take: The Lifelong Impact of Air Pollution”, estimated that around 40,000 premature deaths in the UK per year are attributable to outdoor air pollution, mostly from traffic.

“The 40 micrograms per cubic metre of nitrogen dioxide equivalent is the level set by law at a European level, and is to some extent arbitrary.

“Levels close to but below 40 won't be much less harmful than levels just above.

“There are also other pollutants from traffic fumes, for example particulates, which are not monitored, and whose impacts are less well understood.”

Wycombe District Council confirmed it is investigating the air quality in High Wycombe town centre, as well as other busy roads in the town, and will present the findings this year.

Spokesman for Wycombe District Council, Catherine Spalton, said: “We've commissioned some air quality modelling reports for High Wycombe town centre (including arterial roads such as London Road), Marlow town centre and the M40 corridor.

“The findings will form the basis of a report to Cabinet later this year, which may include recommendations to declare Local Air Quality Management Areas. Should an area be designated, we would of course prepare an appropriate action plan.”