The research, based on the latest updated London Atmospheric Emissions Inventory, shows that every area in the capital exceeds World Health Organisation (WHO) limits for a damaging type of particle known as PM2.5. It also found that 7.9 million Londoners – nearly 95% of the capital’s population – live in areas that exceed the limit by 50% or more. In central London the average annual levels are almost double the WHO limit of 10 µg/m3.
— source theguardian.com 2017-10-06