The average levels of poisonous nitrogen dioxide in the air broke the legal limits at 28 different monitoring sites across Bristol, the latest figures reveal.
Nitrogen dioxide emissions from petrol and diesel engines are one of the biggest causes of deaths from pollution in the UK, so the widespread illegally-bad air quality is what has forced the city council to introduce a Clean Air Zone for the most polluting vehicles.
The council set up air quality monitoring stations across the city, and the latest figures for a yearly average show that nitrogen dioxide levels exceeded the legal limit of 40 μg/m3.
