POLLUTION in some parts of Old Town street are almost twice the legal limit.

Cricklade Street resident Becky Cox discovered the potential harm to health after placing a monitor outside her home.

The monitoring kit, provided by charity Friends of the Earth, measured levels of dangerous nitrogen dioxide in the air over a two-week period.

When the charity’s scientists analysed the results, they found that the monitor picked up an average of 73.5 micrograms per cubic metre of nitrogen dioxide. The annual legal limit is for an average of 40mcg/m3.

Becky, 29, is now calling on the council to do more to try and reduce busy through traffic.

She also wants the council to encourage more sustainable alternatives to driving, such as walking and cycling.

“I frequently find myself coughing and trying to avoid breathing deeply as I walk along the road,” said Becky.

The transport consultant, who has lived in Cricklade Street for three years, said the pollution has also affected her collie-cross dog, Daisy, causing her to sneeze.

She said the high pollution reading had shocked her.

“I had a look at the thousands of other results from air quality monitors across the UK. I struggled to find such a high reading elsewhere, even in Bristol and London,” said Becky, who wrote to the council’s air quality team and South Swindon MP Robert Buckland to report the reading.

She says she wants the council to tackle the use of Old Town as a traffic through-route.

“Walking and cycling links need to be improved along with better public transport services so that people don’t need to rely on their cars to travel through and to the area,” she said.

Becky, who is married, said: “We can’t really afford to move at the moment. Even if we did move it would make it better for us but it doesn’t make the situation better for others.”

Sion Williams, Friends of the Earth South West campaigner, has warned that air pollution is a silent killer, contributing to heart disease, lung cancer and asthma.

“Because you can’t often see it or smell it, people generally don’t realise how bad it is,” she said.

Swindon Borough Council, which measures air pollution at 23 hotspots, said that Becky’s figures should be treated with caution.

According to data shared by the Department for the Environment, Food and Rural Affairs, the concentration of nitrogen dioxide in the air in Swindon did not come near to breaching legal limits in 2015 – the latest year for which data is available.

A spokesman said: “The length of exposure, the types of tubes used, the transportation of the tubes and the analysis used to process the tubes can all have a huge impact on results.

“The short-term limit value for nitrogen dioxide, which represents concentrations on the pavement where people may be exposed for up to an hour, is in fact 200mcg/m3 and this needs to be exceeded 18 times a year before formally breaching EU limits. Weather, time of day and the seasons could also affect NO2 levels.

“We monitor air quality in areas across Swindon by exposing diffusion tubes for month-long periods and then aggregate the data over a year.

"Although a single year’s data is persuasive, we do prefer to see a series of whole years to come to a considered view of air quality at a particular location.”