Lead Research Organisation: Imperial College London
Department Name: School of Public Health


While it has been recognised for some time that small particles from vehicle exhausts and other traffic related pollutants cause a range of health effects, policy within the UK and Europe has not directly targeted these. Emissions from vehicles and ambient air itself are regulated in terms of total particles, with no specific targeting of one component or another. While this is clearly prudent in that it potentially drives reductions in all types of particles, it is also inefficient as it is likely that some particles (or particle components) are more toxic than others. This project seeks to elucidate the more toxic components of the pollution mix in London, with particular emphasis on traffic generated particles. If successful this will inform a more focussed and more efficient policy process for regulating vehicle emissions and ambient air quality. As well as regulating vehicle emissions and ambient air, policy makers - particularly at local and regional government level-can influence air pollution impacts through traffic management and wider planning decisions. Here the project will provide better information on spatial and temporal exposures and their relation to adverse impacts of air quality. This dynamic exposure information will be a major step forward in assessing the scope for more focussed traffic and infrastructure planning and management in London, with possible applications elsewhere in the UK. Even though there is a substantial literature confirming the impact of traffic pollution on health there are still substantial gaps. There is very strong evidence that exposure to traffic pollution causes asthma exacerbations in children and reasonably strong evidence that it may cause other health effects including the onset of childhood asthma, non asthma respiratory symptoms, impaired lung function, total and cardiovascular mortality and cardiovascular morbidity. In this project we will undertake a number of new investigations to examine the relationship between chronic exposure to traffic pollution and health. These will include studies of mothers in pregnancy right through to senior citizens. These innovate studies will include health outcomes rarely if ever available for investigation of air pollution effects (e.g. primary care data, child cardiovascular risk factors). The use of exposure metrics on a fine spatial scale that are in routine use for policy in London will enable exposure response relationships to be used for quantifying policy options in terms of health impact. Further this will enable us to evaluate the health impact of trends in exposure to traffic related air pollution, most specifically the Low Emission Zone for London (LEZ).


10 25 50
Description We found that pregnant women exposed to air pollution (particularly PM2.5) in London during their pregnancy had an increased risk of a low birth weight baby. We found little evidence that road traffic-related noise had an impact on birth weight.

We found that exposure to higher levels of ozone (a secondary air pollutant) and primary traffic non-exhaust related PM2.5 (e.g. particles from vehicle brake/tyre wear) during pregnancy may increase risk of preterm birth and stillbirth. We also found evidence suggesting a possible relationship between long-term traffic-related noise and risk of preterm birth.

This was the first study in the UK and the largest study in the world to look at the joint effects of air pollution and noise on birth outcomes.
Exploitation Route The outcomes of this funding may feed into an ongoing review of evidence linking adverse birth outcomes with maternal exposure to air pollution during pregnancy by the Committee on the Medical Effects of Air Pollutants (COMEAP).
Sectors Environment,Healthcare

Description The evidence for adverse health effects of traffic pollution is not coherent and there is an incomplete understanding of the relative roles of air pollution and noise that are associated with living near a busy road. The TRAFFIC project has advanced this understanding by co-analysis of each hazard. Exposure response relationships specific to traffic sources have been sought with which to evaluate the health impacts of traffic and transport policies.
First Year Of Impact 2017
Sector Environment,Healthcare
Description PI and post-doctoral researcher co-opted as experts to review evidence on air pollution and birth outcomes and provide recommendations
Geographic Reach National 
Policy Influence Type Participation in a guidance/advisory committee
Description Interview for national and international news 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact To inform the wider public of the potential risks of air pollution on pregnancy outcomes in London and the fact that current EU standard levels are not protecting pregnant women and their babies. (examples of engagement with media and news coverage include The Metro ( ); The Guardian ( ); New York Times: ( ); and ITV News ( )
Year(s) Of Engagement Activity 2017