Gas boilers overtake transport as biggest source of air pollution in central London

Gas boilers are now thought to be the primary source of nitrogen oxide pollution in central London as sources such as vehicles decline.

The combustion of natural gas in boilers accounted for 72% of nitrogen oxide emissions within a few kilometres radius of London’s BT Tower between 2021 and 2023. The study was led by researchers at the National Centre for Atmospheric Science and the University of York.

The findings also highlight the success of efforts to reduce the impact of transport such as the London Low Emission Zone and the Ultra Low Emission Zone (ULEZ) to reduce nitrogen oxide emissions from vehicles. Those emissions in central London are estimated to have fallen by about 73% between 2016 and 2025. In addition, the increasing prevalence of Euro 6 vehicles and electric cars has contributed to this decline.

Nitrogen dioxide in outdoor air is associated with adverse effects on health, including asthma and reduced life expectancy.

Professor James Lee, lead researcher on the project...