Air pollution causes 2.5m deaths a year, study claims

Outdoor air pollution is responsible for the deaths of more than two and a half million people around the world each year, according to a study.

The study, published in the Environmental Research Letters journal, estimates that around 2.1 million deaths worldwide each year are associated with particulate matter PM2.5-related cardiopulmonary diseases (93%) and lung cancer (7%).

Recent air pollution problems in Singapore made it difficult to see and forced many residents to wear masks

Recent air pollution problems in Singapore made it difficult to see and forced many residents to wear masks

A further 470,000 premature respiratory deaths per year are caused by ozone, the study – ‘Global premature mortality due to anthropogenic outdoor air pollution and the contribution of past climate change’ – estimates.

In Europe alone, the study estimates that an average of 32,800 people die each year as a result of ozone pollution, while an average of 154,000 premature deaths are caused by PM2.5.

Furthermore, the authors of the study – led by University of Carolina’s Raquel A. Silva and including scientists from the University of Reading, the University of Edinburgh and the UK Met Office – state that their methods may have underestimated the true mortality impact of air pollution.

The study states: ‘As for previous studies that estimate the mortality burden of outdoor air pollution, our methods likely underestimate the true burden because we have limited the evaluation to adults aged 30 and older, and base the analysis on coarse-resolution models that likely underestimate exposure, particularly for PM2.5 in urban areas.’

Climate change

The study also looked at the impact of climate change on air quality, estimating that around 3,700 deaths per year were attributable to the impact of past climate change on air pollution.

According to the study: ‘Climate change influences air quality through several mechanisms, including changes in photochemical reaction rates, biogenic emissions, deposition, and atmospheric circulation.’

However, the authors of the study also state that due to the large variability among models, using a single model to represent past climate change may have ‘significant uncertainties’. As a result, they state, ‘it cannot be clearly concluded that past climate change has increased air pollution mortality’.

Two recent studies also found that just small increases air pollution contributed to a higher risk of both heart failure and lung cancer (see story).

Recently, biomass burning has caused smogs in Singapore (see story) while there have also been well-documented problems with air quality this year in Beijing.