A project quantifying the health and economic impact of NO2 and PM2.5 in Liverpool City Region.
The British Lung Foundation and UK100 commissioned the Environment Research Group (ERG) at King’s College London (King’s) to help produce a health impact and economic assessment associated with air pollution levels of Liverpool City Region (LCR) combined authority. In order to do that, ERG first downloaded the air pollution data of the six combined local authority districts of Halton, Knowsley, Liverpool, St. Helens, Sefton and Wirral forming the Liverpool City Region, which then, combined with relationships between concentrations and health outcomes, were used to calculate the impacts on health from the air pollution emitted in each local authority.
Mortality impact (long –term exposure)
The population in Liverpool City Region would gain around 350,000 to 370,000 life years over a lifetime to 2134 if air pollution concentrations improved as projected from 2011 to 2030, compared with remaining at 2011 concentrations. The average life expectancy of a child born in Liverpool City Region in 2011 would improve by around 2 to 2.5 months for the same comparison.
Taking into account the UK Government’s projected future changes in air pollution concentrations from 2011 to 2030, the population would still be losing between 0.3 to 0.8 million life years in the LCR (a life year is one person living for one year). Put another way, children born in 2011 are still estimated to die 1.5-5 months early on average, if exposed over their lifetimes to the projected future air pollution concentrations in Liverpool City Region. Males are more affected than females, and this is due to the fact that men have higher death rates and die earlier than women.
The monetised benefits over a lifetime of improvements to future anthropogenic PM2.5 and NO2 concentrations, compared with 2011 concentrations remaining unchanged, has been estimated to be between £200 - £210 million on average/year (at 2014 prices).
Despite the projected future improvements in air pollution concentrations from 2011 to 2030, the economic health impact costs in the Liverpool City Region over a lifetime are still between £170 - £480 million on average per year.
Economists assign monetary values to the health benefits of reducing air pollution in cost-benefit analysis in order to compare with the costs of implementing a package of policies. They are not actual costs but a measure of the amount of money society believes it would be reasonable to spend on policies to reduce air pollution (to avoid the adverse health effects of the remaining pollution) or was reasonable to have spent on policies that have already reduced air pollution.
Mortality burden (long –term exposure)
Mortality burden calculations are a simplified calculation at one point in time. They are not suitable for analysing several years in succession because they do not have a mechanism for allowing the number of deaths the year before to influence the age and population size the following year (lifetables do this, see impact calculations above). Nonetheless, they provide a useful feel for the size of the air pollution problem.
In 2011 in the Liverpool City Region the equivalent of between 800 to 1,040 deaths are estimated to be attributable to anthropogenic PM2.5 and NO2. These deaths occur mostly at older ages, as is typical for deaths in the general population.
Impact of Air Pollution on Inequalities
This study shows that adverse health impacts remain and that further pollution improvements beyond those already made are still needed, especially to tackle environmental inequality (in which socioeconomically disadvantaged populations are still among the most exposed). The most vulnerable individuals within the Liverpool City Region are more likely to be exposed to higher levels of air pollution and would benefit the most from further reduction of air pollution. The main clusters of areas associated with both the most deprived and highest levels of air pollution are located in a ring around Liverpool city centre, in central and northern Knowsley and within the central area of St Helens.
Dr David Dajnak
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