Clean air zone impact on health revealed in new study

Greater London's low emission zone (LEZ) and the ultra-low emission zone (ULEZ) are delivering significant public health and economic benefits, according to a new study.

The University of Bath research, published in the Journal of Economic Behavior and Organization, which analysed more than a decade of data from Greater London and Central London, found that the introduction of the LEZ in 2008 and the ULEZ in 2019, significantly reduced harmful pollutants like nitrogen dioxide (NO₂) and particulate matter (PM10). 

This, it says, resulted in a significant drop in sick leave in Greater London, and improved mental well-being and substantial cost savings.

Key findings in Greater London, compared to areas in England without low emission zones, suggest that there was an 18.5% reduction in sick leave following LEZ implementation and a 10.2% decrease in respiratory issues.

It also estimated annual public health savings of more than £37 million, driven by fewer respiratory illnesses and reduced job absenteeism thanks to low emission zones.

Professor Eleonora Fichera, from the University’s Department of Economics and Centre for 21st Century Public Health, said: “These policies are not just environmental wins, they’re also reducing labour market absenteeism and improving Londoners’ life satisfaction. 

“Clean air makes for healthier, happier, more productive communities.”

Dr Habtamu Beshir, who led the research at the University of Bath and is now based at UCL, added: “Our work shows that clean air policy is smart policy. It protects health, saves money, and enhances quality of life - making the case for clean air initiatives stronger than ever.”

The study employed a quasi-experimental method, analysing changes in affected and unaffected areas before and after policy rollout. 

The data shows that when LEZ was tightened in Phase 2 (July 2008), NO₂ levels dropped by 5.8% and PM10 by 9.7%. 

ULEZ, the strictest policy of its kind globally, delivered even greater reductions. NO₂ was down 21% and PM10 down 15%, estimated by comparing Central London to other areas outside Greater London, before and after ULEZ was introduced.

Fichera said: “With the World Health Organization estimating 4.2 million premature deaths globally each year due to air pollution, these findings signal the urgent need for similar transport policies in other major cities not just in the UK but around the world.”

The Univesity of Bath research comes in the wake of a separate report from City Hall, published last month, which claimed particle emissions (PM2.5) from vehicle exhausts are estimated to be 31% lower in outer London in 2024 than they would have been without the ULEZ expansion.

Alongside NO2 and PM2.5 reductions, the report says NOx (Nitrogen Oxides) emissions from cars and vans are also estimated to be 14% lower in outer London.

The biggest reductions in NO2 levels have been in central London (54%), according to the report, but there have also been reductions in inner London (29%) and outer London (24%).