Prosecutor Michael Smith said Mr Shaw, 37, was breathalysed at the scene and gave a reading of 83 microgrammes per 100 millilitres.

BBC: Leeds & West Yorkshire

However, a recent review of evidence carried out by WHO found there were now concerns about a health impact at levels much lower than 10 microgrammes per cubic metre.

BBC: Dust from recycling plants 'puts residents at risk'

Xinhua says that readings in Beijing for the tiniest pollution particles - called PM2.5 - reached more than 400 microgrammes per cubic metre on Thursday, which is considered "dangerous".

BBC: Smog and sandstorm engulf China's capital

One study by the American Cancer Society found that death rates from lung cancer increased 6% for every additional 10 microgrammes of fine particles in a cubic metre of air.

BBC: Traffic

Its guidelines say average concentrations of the tiniest pollution particles - called PM2.5 - should be no more than 10 microgrammes per cubic metre but UK standards allow up to 25.

BBC: Dust from recycling plants 'puts residents at risk'

Levels found by the Health Protection Agency in the vicinity of the Plevins plant were recorded at 8.2 microgrammes per cubic metre while levels outside Armstrongs were 8.8 - both well within the acceptable levels.

BBC: Dust from recycling plants 'puts residents at risk'