A project quantifying the health and economic impact of NO2 and PM2.5 in Bristol City.
UK100 commissioned the Environment Research Group (ERG) at King’s College London (King’s) to produce a health impact and economic assessment associated with current and future air pollution levels of Bristol City, the largest city in the South West of England, formed of four parliamentary constituencies (Bristol East, Bristol North West, Bristol South and Bristol West). In order to do that, ERG first downloaded the air pollution data in Bristol City, 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 constituency.
Mortality impact (long –term exposure)
The population in Bristol would gain around 150,000 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 Bristol in 2011 would improve by around 2 to 3 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 90,000 to 300,000 life years in Bristol (a life year is one person living for one year). Put another way, children born in 2011 are still estimated to die 1.5-6 months early on average, if exposed over their lifetimes to the projected future air pollution concentrations in Bristol. 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 up to £80 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 Bristol over a lifetime are still between £50 - £170 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 Bristol the equivalent of between 200 to 260 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, ethnic groups, population change, migration and students
Although Bristol is considered to be one of the relatively less deprived English core cities, Bristol deprivation ‘hot spots’ are amongst some of the most deprived in the country. Overall, Bristol does not particularly show environmental inequality (in which socioeconomically disadvantaged populations are among the most exposed), except for the area of Lawrence Hill identified as having both some of the highest levels of deprivation and air pollution in Bristol as well as by far the highest Black and Minority Ethnic population in Bristol.
The highest concentrations of PM2.5 and NO2 air pollution in Bristol have been found to coincide with areas of exceptional population growth (70% population change between 2007 and 2017 in Central, 55% in Hotwells & Harbourside and 39% in Lawrence Hill wards), areas where most recent migrants tend to live (in inner city areas of Bristol in particular in Central and Lawrence Hill wards and some part of Hotwells & Harboursidse) and areas where most students live during term time (including Central, Cotham, Clifton Down, Hotwells and Harbourside and Clifton wards).
This study shows that adverse health impacts remain and that further pollution improvements beyond those already made are still needed. All Bristol citizens would benefit greatly from a reduction in air pollution concentrations.
Dr David Dajnak
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