Gas boilers have replaced road transport as the main source of nitrogen oxide (NOx) emissions in central London, new research shows.
The study, led by Professor James Lee at the University of York, measured air pollution at the BT Tower in the UK capital’s West End.
The largest source of NOx emissions in central London has transitioned from road transport to space heating, according to the research. It found that the combustion of natural gas in boilers accounted for 72% of NOx emissions within a 2-3km radius of the BT Tower between 2021 and 2023.
The research, published in the journal Environmental Science & Technology, also found that NOx emissions from vehicles in central London are estimated to have fallen by about 73% between 2016 and 2025.
The researchers said the findings highlight the success of transport interventions such as the Greater London Authority’s Ultra Low Emission Zone in significantly reducing NOx emissions from vehicles.
They added that, in natural gas-reliant urban environments, space heating may now be the priority sector for further NOx emissions intervention.
Professor Lee said: ‘While talk of switching from gas to heat pumps is mainly framed around the decarbonisation benefits, it would be a major gain for air quality too.’
