Lead Research Organisation: University College London
Department Name: Bartlett Sch of Graduate Studies


See text for lead organisation (as discussed with NERC Env Health Programme Manager: Dominque Balharry)


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Description The key findings of relevance to public policy may be summarized follows:

Air pollution exposure and impacts
- Analyses of the sources of pollution show that, for particles of maximum aerodynamic diameter less than 2.5 microns (PM2.5) - those which are thought to carry the main risk for health - emissions from power generation and transport sectors are both major contributors, as is combustion in the non-industrial sector. But the largest contribution to PM2.5 air pollution across the UK overall is from the agriculture sector (relating to use of fertilizers, land management etc). Action in all these sectors is therefore important for control of particle pollution.
- Although agriculture is the largest contributor to PM2.5 concentrations spatially, it is less important a source of primary particles (i.e. those directly released into the atmosphere by wind, combustion processes, or human activities) as opposed to secondary particles derived from the oxidation of primary gases such as sulphur and nitrogen oxides into sulfuric acid and nitric acid.
- The importance of the transport sector is accentuated by the proximity of populations to emissions from this sector especially in urban areas, and they are also important for nitrogen oxides (NOx), comprising nitric oxide and nitrogen dioxide. There is emerging evidence that nitrogen dioxide may carry risks for health that are independent of those attributable to particle components of air pollution. Although the evidence does not allow precise quantification of this NO2-related health risk, it gives greater importance to action to control emissions from motor vehicles, especially diesel cars and lorries.
- Reduction of air pollutant emissions from industrial, non-industrial, transport and agriculture sources appear likely to increase atmospheric concentrations of ozone (O3), largely as a result of the reduced 'titration effect' of nitrogen dioxide (the atmospheric chemical reactions that breakdown O3). In consequence, emissions control policies over coming years are likely to exacerbate the exposure of human populations to ozone, rather than to reduce it.
- Climate change alone is likely to have only modest impacts on atmospheric pollution unless accompanied by changes in emission sources (a small effect on PM2.5, some modest local increases in NOx which may titrate more ozone, mixed effects on coarse particle fractions), but models suggest the potential for substantial increases in temperatures, especially during summer months in southern Britain: some models indicate mean July temperatures that increase by as much as 6 or 7 degrees Celsius under high emissions trajectories - which would represent a substantial hazard for public health.

Exposure patterns with socio-economic deprivation
- Most pollutants show a gradient of higher exposure with increasing socio-economic deprivation across the UK, although the variations based on 5x5 km grid average pollution levels are relatively modest (mainly a few percent difference between the least and most deprived deciles of the population). NOx, total PM2.5, primary PM2.5, and elemental carbon (EC) and organic carbon (OC) all show clear increases in concentration with greater SE-deprivation, with the greatest increases in PM2.5, primary PM2.5 and NO2 concentrations occurring from the middle of the deprivation distribution to the most deprived deciles. Ozone shows an inverse relationship with socio-economic deprivation.
- Modelling the effect of the sectoral emission sources suggests that control policies will have little effect on the socio-economic gradient in exposure patterns, and in many cases are likely to lead to a small increase in the gradient even though overall air pollution burdens would be reduced including for the most deprived populations.
- Populations in the most deprived decile of the population are estimated to have 4% greater years of life lost due to PM2.5 exposure than the least deprived group experienced.

Health risks
- Analyses of data from the AWESOME project on the health effects of short term exposure to particle pollution and its components suggest generally weak (and generally statistically insignificant) relationships with health outcomes. They do not add appreciably to the existing evidence base. They do however provide some mixed evidence for the adverse effects of nitrogen dioxide in relation to the risk of admission to hospital with heart attacks or other acute myocardial ischaemia.
- Analyses do confirm clear evidence for temperature related risks, however. An important new finding based on linkage of housing characteristics to epidemiological data is that vulnerability to heat risk appears to depend on the characteristics of the home in which you live. People who live in dwellings that are predicted to be more likely to overheat (have relatively high indoor temperatures during hot weather) carry an appreciably greater risk of mortality attributable to heat, especially during more extreme heat. This suggests potential for adaptations to dwellings to reduce heat exposure and associated risks to health.
- In further modelling work, suggests that dwelling characteristics are appreciably more important that the urban heat island effect in determining population vulnerability to heat.

Housing as a determinant of exposure to outdoor air pollution
- Other work provided evidence that built form and building envelope characteristics of dwellings (the exposed external surface area, the internal volume, the permeability of the building fabric etc) appreciably alter the infiltration of outdoor pollution into the indoor environment. In London, older detached and semidetached dwellings had the highest indoor/outdoor pollutant ratios, modern purpose-built flats the lowest.
- Because of such differences in the ingress of outdoor pollution into the home, the dwelling form has a potentially important influence on human exposure to particle and other outdoor air pollutants, with differences of around 50% between the least and most 'leaky' dwellings.
- Such differences suggest that interventions aimed at altering the ventilation characteristics of dwellings may offer important opportunities for protecting against air pollution. However, care is need to balance the effects of protection against outdoor pollution with impacts on exposure from sources of exposure inside the home, which would increase with increased air tightness.
Exploitation Route See above for the key findings of relevance to public policy.
Sectors Construction,Energy,Environment,Transport

Description - We continue to be involved in a series of meetings with the GLA to determine how the outputs from AWESOME can inform relevant policy e.g. aspects of the London Plan. - The AWESOME work also fed in to the development of the novel Health Impacts of Domestic Energy Efficiency Measures (HIDEEM) tool for the UK Department of Energy and Climate Change (DECC). This included the construction of micro-environmental stock models to quantify indoor environmental conditions and calculate the monetary value of the health impact associated with energy efficiency changes in the housing stock. -A joint project involving UCL and London Borough of Hounslow, explored the combining of health, building portfolio and overheating models from UCL and PHE, with other data bases at the borough level in order to flag-up properties/persons at risk from overheating. Having learnt many lessons about integration od different data bases, interest has been expressed by the GLA and suitable funding is being sort. Additionally, outcomes are being integrated in The National Institute for Health Research Health Protection Research Unit (NIHR HPRU) project involving UCL, PHE and LSHTM.
First Year Of Impact 2012
Sector Communities and Social Services/Policy,Construction,Energy,Environment,Government, Democracy and Justice
Impact Types Policy & public services

Description University of East Anglia 
Organisation University of East Anglia
Country United Kingdom 
Sector Academic/University 
PI Contribution Staff time, expertise, intellectual input, access to data, equipment and facilities
Collaborator Contribution Expert opinion, staff time, assistance with publications,
Impact Publications
Start Year 2011