London air pollution kills almost 9,500 a year, study finds

London air pollution is estimated to have killed nearly 9,500 people in 2010 — almost double the number previously thought — according to new research published today (July 15) by the Mayor of London.

River Thames shown during an episode of air pollution in February 2013 (Photo: Simon Birkett, Clean Air in London)

The report produced by scientists at King’s College London (KCL) marks the first time that the health and economic effects of nitrogen dioxide have been quantified, as all previous studies have focused on just particulate matter (PM2.5).

As such, today’s figures, which cover the year 2010 — the most recent year for which quantified figures are available — are higher than previous estimates because they combine the effects of both pollutants.

The report estimates that there were 5,900 deaths in London associated with long term exposure to nitrogen dioxide (NO2) in 2010, and 3,500 deaths associated with PM2.5 that year, bringing the overall figure to just under 9,500 premature mortalities.

However, according to the report, based on KCL projections, this figure ‘will have decreased significantly’ in 2012 and in 2015, while policies such as the ultra low emission zone (ULEZ) planned for central London in 2020 are also expected to result in a future drop in estimated mortality figures.

The study also shows that nearly half of the health effects of long term exposure to air pollution in 2010 in London were caused by pollution sources from outside the capital.

Indeed, 75% of cardiovascular hospital admissions that year are thought to have been the result of non-London sources of PM2.5, such as ‘diesel fumes and industrial emissions transported from the continent’.

Significance

Although it only covers London, today’s research is significant as it potentially signals the wider picture of the impact of air pollution across the rest of the UK.

Current official estimates put the number of premature deaths in the UK as a whole caused by particulate matter at around 29,000 each year — but this figure does not include the impacts of nitrogen dioxide because it has previously been difficult for scientists to separate the health impacts of the two pollutants to give an accurate overall estimate.

But while there are currently no estimated figures for the number of premature deaths from nitrogen dioxide covering the whole of the UK, the government’s Committee on the Medical Effects of Air Pollutants (COMEAP) is finalising these calculations and is expected to make an announcement later this year (see AirQualityNews.com story).

As with today’s new estimates covering London, it has been suggested that COMEAP estimates due later this year could see the overall number of estimated premature deaths from NO2 and PM2.5 combined in the UK nearly double the current 29,000 figure.

London Mayor Boris Johnson launching the Breathe Better Together air quality campaign earlier this year with school pupils inside an inflatable globe

Current estimates already list air pollution as responsible for more premature deaths in the UK than obesity, alcoholism and road traffic accidents combined, but the inclusion of nitrogen dioxide impacts in the figures could see it come closer to rivalling smoking, which is responsible for the deaths of around 80,000-100,000 and is the UK’s biggest killer.

London Mayor

2010 is the most recent available ‘base’ year for the London Atmospheric Emission Inventory, which provides understanding of air quality in the city, but projections from 2008, 2012, 2015 and 2020 are also included in the report based on the data from 2010.

The London Mayor, Boris Johnson, said that because today’s estimated figures are five years old, they do not take account of a number of planned policies designed to cut pollution in London in future.

According to the Mayor, as a result of policies such as introducing 1,300 hybrid buses, age limits for taxis and tighter low emission zone standards, almost four million lives are expected to be saved between 2010 and 2020.

However, he said this estimate does not take into account the impact of the ULEZ from 2020, which the Mayor said would result in further reductions in London’s air pollution.

The Mayor said of the report:

“This is a snapshot of the true impact of air pollutants on our health.”

And, commenting today, Mr Johnson also called for the “help and strong support of the government and the EU to effectively win London’s pollution battle and target the enormous amount of toxic air transported into our great capital internationally”.

Author of the report, Dr Heather Walton from the Environmental Research Group at KCL, said: “The health evidence on the health effects of nitrogen dioxide has strengthened in recent years, including evidence linking long-term exposure to nitrogen dioxide with mortality. It is now thought that there is an additional effect beyond that previously quantified for the effects of long-term exposure to PM2.5.

“This report quantifies the possible maximum size of this additional effect in London in 2010, expressed as loss of life years and equivalent deaths, acknowledging uncertainties such as the contribution from traffic pollutants other than NO2. It is important that these types of calculations are funded, published and debated to ensure the health benefits of policies to reduce emissions of air pollutants such as nitrogen dioxide are fully recognised and used to design the best policies for the future.”

The report also includes a 2010 borough breakdown highlighting the estimated number of attributable deaths associated with pollutants in each area based on the local concentration and numbers in the local population.

Related Links:

—King’s College London report — ‘Understanding the Health Impacts of Air Pollution in London’