Annual average NO2 levels in London 2016-2019, by zone and site type
The average annual nitrogen dioxide (NO2) levels in London have been declining in recent years. In 2016, NO2 levels at roadside sites in central London averaged 91 micrograms per cubic meter. By 2019, this had fallen to 61 micrograms per cubic meter, a 33 percent reduction. In 2019, the Ultra Low Emission Zone (ULEZ) was introduced in central London. Operating 24 hours a day, seven days a week, drivers of vehicles who enter this zone which do not meet ULEZ emission standards are required to pay a daily charge.
