Central London has a particular problem with potentially deadly air pollution caused by nitrogen dioxide, but it is not all the fault of drivers with diesel cars. Buses and buildings are also playing a significant part.
Transport is the largest single factor in the production of harmful NO2 and the finger is often pointed at cars with diesel engines. These type of vehicles make up 50% of all new sales in the UK and the switch away from petrol, encouraged by the Government, has had some benefit for other types of emissions.
But data analysis by the think tank Policy Exchange on the sources of NO2 in London shows that diesel cars are only part of the story and the figures for Central London are different to that for Greater London as a whole.
Nearly every borough is failing to meet the legal limit for levels of NO2. Long term exposure to high levels can lead to respiratory disease and a recent study by Kings College London, reported by Urbs, estimated that it may be killing 5,800 people a year.
Transport is responsible for 45% of NO2 emission across Greater London. Diesel vehicles including cars, taxis, buses and HGVs account for most of this, with 11% attriibuted to diesel cars, the same as HGVs.
The figures for Central London reveal a similar rate of NO2 from transport, but the nature of traffic in the centre of the city means that busess account for 3 times the amount of NO2 produced by diesel cars.
The other significantly different factor in Central London is the NO2 emission rate from non-domestic burning of gas, ie powering the offices, shops and businesses. This accounts for a third of NO2 emissions in Central London compared to 8% for Greater London.
The recent Volkswagen emission test scandal has led to renewed concern about the real level of diesel car pollution. But this data shows that while cleaner cars are needed the capital also needs a greener bus service and more energy efficient buidlings to tackle the problem of NO2 more widely.