An expert committee on air quality has today (22 August) suggested that between 28,000 and 36,000 premature deaths in the UK every year could be linked to long-term exposure to air pollution.
The figures come after the panel, which issues advice to government, detailed its findings on research into the possible loss of life in the UK caused by exposure to nitrogen dioxide.
COMEAP – the Committee on the Medical Effects of Air Pollutants – completed the long awaited report this summer – bringing to a close a project which has been ongoing since 2014 (see airqualitynews.com story).
Nitrogen dioxide (NO2) is a pollutant which mainly gets into the air from the burning of fuel. Breathing air with a high concentration of NO2 can cause or worsen respiratory problems, studies have found.
Estimates previously published by COMEAP in 2009 suggested that the number of deaths linked to exposure to another pollutant associated with fuel combustion as well as other sources, fine particles (PM2.5), were in the order of 29,000 per year.
COMEAP’s latest work had sought to gain a better understanding of the links between NO2 and health, and potentially provide a more complete overall picture of the health impact of air pollution in the UK.
Initially it had been hoped that the COMEAP report would be able to provide a specific figure for deaths singly attributable to NO2, in the same manner as the 2009 study on PM2.5.
COMEAP examined existing papers compiled in a number of countries, including the UK, looking at the effect that long-term exposure to NO2 may have on mortality.
However, after several years of analysis and deliberation over the available data, Committee members concluded that uncertainty in assessing the impact of NO2 individually compared to other pollutants, such as PM2.5, made it difficult to arrive at an individual figure wholly attributable to NO2.
One reason for this is that both pollutants can often be emitted from a single source, for example from road transport, meaning that it can be difficult to differentiate between the individual effect of each pollutant.
In a statement published today alongside its report, COMEAP said: “Firstly, there were differences between the studies, making it hard to compare them. In addition, other air pollutants, such as particulate matter, are also harmful when inhaled. These are often emitted from the same sources as NO2 (for example, traffic), leading to difficulties in assessing the effect of NO2 itself, on people’s health.
“Therefore, not all of our conclusions are unanimous. This report presents the views of committee members who dissent from the majority view, as well as the views of the majority of members, to reflect this.â€?
As a result of this, COMEAP has put forward estimates which take into account the possible overlap between the pollution sources, to prevent figures from ‘over-estimating’ the overall impact of air pollution on human health.
The Committee added in its statement: “The methodology of this present report allows for calculations to be made on the basis of either particulate matter known as PM2.5 or NO2, and using the higher of the two estimates. The results should not be added together as this would lead to an over-estimation of the effects.
“The report also includes exploratory calculations based on both PM2.5 and NO2, using information from studies in which the overlap of effects associated with the two pollutants has been accounted for.
“Using these two approaches, the range of estimates of the annual mortality burden of human-made air pollution in the UK is estimated as an effect equivalent to 28,000 to 36,000 deaths.â€?
These figures are thought to be the closest overall estimate to the mortality impact of air pollution in the UK – however as more research on the impacts of nitrogen dioxide is carried out, this could yet be further refined.
An influential report published by the Royal College of Physicians in 2016 suggested that the total number of deaths attributable to air pollution in the UK is likely to be in the order of 40,000, based in part on COMEAP’s own conclusions on the impact of PM2.5 on human health (see airqualitynews.com story).
Nitrogen dioxide: effects on mortality