What does air pollution do to our bodies?

The countdown has begun to the launch of one of the world's boldest attempts to tackle air pollution. From next Monday, thousands of drivers face paying a new charge to enter central London. The aim is to deter the dirtiest vehicles in an effort to reduce diseases and premature deaths. The initiative comes as scientists say the impacts of air pollution are more serious than previously thought. The mayor of London, Sadiq Khan, told the BBC that the threat of air pollution, which is mostly invisible to the naked eye, is "a public health emergency".