Air Quality and Social Deprivation in the UK: an environmental inequalities analysis Final Report to Department of Environment, Food and Rural Affairs AEAT/ENV/R/2170, June 2006 = AEAT/ENV/R/2170 Air Quality and Social Deprivation in the UK Final Report v1.1 Title Air Quality and Social Deprivation in the UK: an environmental inequalities analysis – Final Report to Defra, Contract RMP/2035 Customer This study was undertaken on behalf of Defra under Contract RMP/2035. This contract also provided air quality datasets for ONS Neighbourhood Statistics. Funding originated from the Neighbourhood Renewal Unit (part of the Department for Communities and Local Government) Customer RMP/2035 reference Confidentiality, Copyright AEA Technology plc All rights copyright and reserved. Enquiries about copyright and reproduction reproduction should be addressed to the Commercial Manager, AEA Technology plc. File reference netcen/ED48212/Final Report v1.1 Reference number AEAT/ENV/R/2170 Address for Netcen, AEA Technology Correspondence Gemini Building, Fermi Avenue Harwell Business Centre Didcot, Oxon OX11 0QR Telephone 0870 190 6554 Facsimile 0870 190 6318 [email protected] netcen is a operating division of AEA Technology plc netcen is certificated to ISO9001 & ISO 14001 Name Signature Date Authors Steve Pye 8th June 2006 Katie King James Sturman Reviewed by John Stedman 8th June 2006 Approved by Geoff Dollard 8th June 2006 Note that the air quality datasets used in this study are experimental and are not classified as National Statistics. Front page photograph: © Jon Bower, 2006 netcen ii AEAT/ENV/R/2170 Air Quality and Social Deprivation in the UK Final Report v1.1 netcen iii AEAT/ENV/R/2170 Air Quality and Social Deprivation in the UK Final Report v1.1 Executive summary This final report describes the work under Task 3 Policy analysis of the Neighbourhood Statistics on Ambient Air Quality Contract (RMP/3035). The main objective of the policy analysis is to further the current understanding of air quality impacts on local communities with differing levels of social deprivation . Environmental inequalities arise where specific communities, such as the most deprived, experience a poorer environmental quality. Understanding and tackling such inequalities is important in the context of sustainable development, where socio-economic issues need to be considered along side environmental ones, and in view of the emerging agenda on social justice in the UK. To further investigate environmental inequalities associated with air quality, the following analyses were undertaken in this study: Comparison of levels of deprivation and air quality concentrations across the UK Assessment of changes in trends at different spatial resolutions e.g. at the urban level Consideration of whether populations experiencing air pollution higher than the Air Quality Strategy (AQS) objective values tend to be more deprived through assessment of deprivation levels in Air Quality Management Areas (AQMAs) Assessment of the potential impact of pollution from large point sources on communities based on their level of deprivation Examination of whether pollution levels and associated impacts suffered by the most deprived communities could be compounded by increased susceptibility The relationship between distribution of pollutant concentrations and areas of social deprivation is complex. It depends on the pollutant in question and differs in different cities and regions of the UK. Consequently it is difficult to draw general conclusions that apply everywhere. There are however a number of important key findings summarised below, which feed into proposed recommendations at the end of this section for further consideration by Defra. UK wide analysis Inequalities in the distribution of pollutant concentrations (higher relative concentrations in the more deprived deciles) can be observed for England, Scotland and Northern Ireland for nitrogen dioxide (NO 2) and particulate matter (PM 10 ), and for sulphur dioxide (SO 2) in England and Northern Ireland. The overall level of inequality is reduced by high concentrations of these species also 1 being observed in the least deprived deciles. For NO 2 and PM 10 , this distribution can largely be explained by the high urban concentrations driven by road transport sources, and the higher proportion of deprived communities in urban areas. Inequalities are greater in areas with poorest air quality for the above pollutants. In such areas, the population is characterised by higher levels of deprivation, indicating greater inequalities in such areas than observed at the national level. In Wales, the trend is different for NO 2 and SO 2, with the highest average concentrations experienced by the least deprived. Above average concentrations are also observed in the most deprived deciles. For PM 10 , both the most and least deprived deciles experience the highest average concentrations. This different trend is due to the location of more prosperous communities in urban areas 1 A decile refers to 10% of the population characterised by a specific level of deprivation, decile 1 being the most deprived and decile 10 being the least deprived. netcen iv AEAT/ENV/R/2170 Air Quality and Social Deprivation in the UK Final Report v1.1 experiencing higher pollution due to road transport sources, and a significant proportion of more deprived communities residing in areas with lower levels of road transport emissions e.g. South Wales valleys. This distribution can be clearly seen in Figure 3.6. The ground level ozone (O 3) trend is the inverse of that observed for NO 2, with relatively lower concentrations experienced by the most deprived deciles, with the exception of Wales, where both the most and least deprived deciles experience the lowest concentrations. This distribution is due to generally lower O 3 concentrations in urban areas, due to the NOx titration or ‘quenching’ process (destruction by NO 2 of O 3 close to sources of nitrogen oxides (NO and NO 2), such as road traffic). 2 In future years, the numbers of people experiencing high air pollution is significantly reduced based on existing and planned policies. Inequalities however persist in some areas despite these improvements, although the population experiencing concentrations above the AQS objective values is much smaller. It appears that policies result in concentration reductions across all deciles but because the highest values tend to be in the most deprived deciles, many are not reduced below stated objectives by 2010. The average values determining country trends are based on a significant number of pollutant concentration values within each deprivation decile. There is wide variation between these values, which needs to be recognised when interpreting the country trends. Variations in analysis scale, deprivation measures and pollution data Different analyses were undertaken to further investigate the observed UK wide trends, through changes to analysis scale, the way deprivation was measured, and the type of pollution data. The distribution of population deciles across urban and rural areas is a key determinant of the country trend. In urban areas, a ‘flatter’ trend can be observed due to high air quality concentrations across all deprivation decile areas. Lower concentrations are more commonly observed in rural areas, which often have larger mid decile populations. The national trend represents a combination of these trends, and tends to show high average concentrations in the most and least deprived deciles, and much lower concentrations in the mid-deciles, which tend to be rural. Consequently, the observed shape of the distribution curve is ‘U’ shaped rather than flat. Limited variation in trends was observed for different regions of England, and between different urban areas of the UK. Generally, all reflected the national trends (although urban trends showed less variation, as discussed above, and as a result less marked inequalities). How deprivation is defined – through the indicators used and relative weightings used in the overall deprivation index - influences the resulting national trend. Our analysis has shown that the level of inequality can change if the definition of overall deprivation is changed. For example, if we measure deprivation on the 2 Whereas nitrogen dioxide (NO 2) participates in the formation of ozone, nitrogen oxide (NO) destroys ozone to form oxygen (O 2) and nitrogen dioxide (NO 2). For this reason, ozone levels are not as high in urban areas (where high levels of NO are emitted from vehicles) as in rural areas (as shown in Figure 3.2). As the nitrogen oxides and hydrocarbons are transported out of urban areas, the ozone-destroying NO is oxidised to NO 2, which participates in ozone formation. netcen v AEAT/ENV/R/2170 Air Quality and Social Deprivation in the UK Final Report v1.1 basis of income or health only, the resulting level of inequality differs to an analysis that uses the overall deprivation index (known as the Index of Multiple Deprivation, or IMD). Roadside concentrations were compared with deprivation levels. Similar trends were observed to those in the countrywide analysis (more deprived populations experiencing higher concentrations), illustrating the importance of road transport sources in determining the England distributions. Communities in Air Quality Management Areas (AQMAs) AQMA populations, who are likely to experience high pollution levels by virtue of the designation of an AQMA, are disproportionately deprived