Air contaminated with pollutants such as ozone and tiny particles could cause the premature death of about 6.6 million people a year by 2050 if nothing is done to improve air quality, scientists warned on Wednesday.

 

In a study published in the journal Nature, they found that outdoor air pollution already kills about 3.3 million people a year worldwide. The majority of those deaths are in Asia where residential energy emissions, such as those from heating and cooking, have a major impact.

 

And that toll could double over the next 35 years, the researchers warned, unless clean-up measures are taken.

 

Air pollution deaths are most commonly from heart disease, strokes or a lung disease called chronic obstructive pulmonary disease (COPD). It is also linked to deaths from lung cancer and acute respiratory infections.

 

Calculating the health and mortality effects of outdoor air pollution on a global scale is not easy, partly because air quality is not monitored in every region and the toxicity of particles varies depending on their source.

 

So for this study, the researchers combined a global atmospheric chemistry model with population data and health statistics to estimate the relative contribution of different kinds of outdoor air pollution, mainly from so-called fine particulate matter, to premature deaths.

 

Their results show that in India and China, for example, emissions from heating and cooking, have the largest death toll, while in much of the United States and a few other countries, emissions from traffic and power generation are crucial.

 

In the eastern United States and in Europe, Russia and East Asia, agricultural emissions are the biggest source of the kind of fine particulate matter that gets into people's lungs, causing illness, disability and death.

 

However, according to a report from the World Health Organization published in 2014, air pollution kills about 7 million people worldwide every year, with more than half of the fatalities due to fumes from indoor stoves.

 

PHOTO: Buildings are seen through thick haze in downtown Shanghai November 7, 2013.

CREDIT: REUTERS/ALY SONG.