International air pollution linked to 1 million deaths in one year

More than 1 million premature deaths in 2007 were linked to fine particulate matter in air pollution emitted as a result of international trade.

Air pollution is an international problem, not just because it can blow from one country to a neighbouring country, or even from one continent to the other, from Asia to North America. It's also exchanged around the world through international trade – products ordered in Europe but made in China lead to increased air pollution in the latter.

A study in the journal Nature has traced the emissions associated with international trade – linking demand in one region to production in another, to the pollution arising from the production, and the estimated deaths caused by that pollution. It is the first study of its kind to assess the scale of the deaths from air pollution associated with international trade.

The study took a snapshot of these interactions in 2007, using four different models to assess the effects of trade as well as looking at the physical transport of air pollution from one world region to another, covering a total of 228 countries.

It focused on PM 2.5 – tiny particles of soot that are emitted when fuels are burnt – which accounts for more than 90% of deaths due to air pollution. Exposure to these particles increases mortality by boosting someone's risk of heart disease, stroke, lung cancer and chronic obstructive pulmonary disease.

Of a total 3.45 million recorded premature deaths in 2007, about 12% (414,000) were traced back to pollutants emitted that had travelled from another region. About 22% (760,000) were traced to goods and services produced in one region and consumed in another.

In other words, the effects of pollution from international trade were linked to 50% more early deaths worldwide than air pollution blowing from one region to another.

"Developed countries should encourage sustainable consumption behaviour to mitigate the negative impact of their consumption on the environment. Developing countries should improve efficiency and structure of economy to reduce local emissions," said study author Qiang Zhang of Tsinghua University, China, at a press briefing.

"International collaborations on promoting advanced emission control technology would have great health benefits to both developed and developing countries."

Study co-author Dabo Guan of the University of East Anglia added in a statement: "Premature mortality related to air pollution is more than just a local issue and our findings quantify the extent to which air pollution is a global problem.

"International trade is further globalising the issue of air pollution mortality by allowing production and consumption activities to be physically separated."