Revealed: The most polluted street in Britain – Yorkshire Post special report

Read more plus background reports in Saturday's Yorkshire Post

The high levels of a gas linked to respiratory problems are amongst the worst in the country and can be revealed as figures also show Bradford is home to Britain's most polluted street.

A Yorkshire Post study of air quality across the region found levels of the pollutant on the remote North York Moors breached permitted levels on 40 separate occasions last year.

The gas - ground-level ozone - can cause eye, nose, throat and chest irritation, coughs and headaches, with sufferers of bronchitis, respiratory allergies and asthma particularly at risk.

The levels recorded at High Muffles, a secluded moorland hamlet mid-way between Pickering and the 'Heartbreat' village of Goathland, were the second-worst in Britain last year.

Experts blame polluting gases which have blown into the National Park from across England and mainland Europe reacting with sunlight during spells of good weather to create high levels of ozone.

Our study also discovered serious air quality problems in urban areas across Yorkshire, with dozens of locations from small market towns to large metropolitan cities breaching acceptable levels of Nitrogen Dioxide (NO2), the main pollutant found in vehicle exhaust fumes.

It follows a report last week by a group of MPs which warned air pollution is responsible for the early deaths of up to 50,000 people in Britain each year - more than passive smoking, road accidents or obesity.

Yorkshire's two most toxic roads are both located in Bradford, where Shipley Airedale Road can today be named as Britain's most polluted street after higher average levels of NO2 were recorded there than on any other street in the country.

Its annual average level of 108 micrograms per cubic metre of air was nearly treble the Government's permitted limit. Council officials described the figure as "raw data" and said investigations were underway as to why levels appear to be so high.

High levels of pollution were also found in York. Four of the region's six highest recorded levels of NO2 were taken within the medieval city, with levels more than double the permitted limit.

York's famously narrow streets, coupled with significant amounts of through-traffic, have been blamed for the problem.

But it is the pollution issues high up on the isolated North York Moors which will come as the greatest shock.

Health campaigners last night voiced their concerns and warned that a hot summer could cause further problems, as ground-level ozone only forms during particualrly sunny spells.

Mikis Euripides, director of policy at Asthma UK, said: "These findings are very concerning, as we know air pollution has a severe impact on the health and the quality of life of people with asthma. If air pollution is left unchecked in Yorkshire it could have a serious impact on the health of the 450,000 people with asthma in the region."

Park authorities, council officers and officials from the Department for the Environment, Food and Rural Affairs (Defra) are all aware of the issue on the Moors, but say the only way to combat it is by reducing underlying pollution levels across the UK and Europe.

Steven Richmond, health and environment manager at Ryedale District Council, said: "Ozone is a trans-boundary pollutant - a lot of it drifts over from Europe, so we have no control over it here. It's something the Government is aware of and people are trying to do something about in the long term. We obviously can't and wouldn't want to reduce levels of sunshine, so the way to do it is to minimise the Nitrogen oxides - and you do that through regulations across the EU.

"You would expect when you're up in the forests of Ryedale that the air is clean and free from pollutants, but that's not always the case. But if I had the choice of where I was going to spend my recreation time, I would rather spend it up there than in a town centre where you're getting direct pollution."

Rachel McIntosh of the North York Moors National Park Authority said the data was from just one monitoring site, so could not be taken as representative of the whole of the North York Moors.

"The number of days when the levels exceed the standard represent less than 13 per cent of the total year so people certainly shouldn't be put off coming here," she said.

"Rises in ozone levels are largely down to weather patterns and are therefore out of our control, and we certainly weren't the only place where levels went up."