About 5.5 million people around the world die prematurely every year from breathing polluted air, and the majority of those deaths are occurring in China and India, where factories and coal-fired power plants are fueling economic growth, according to a report released Friday.
The authors said the findings show that disease from air and household pollution ranks as the No. 2 cause of death worldwide. It comes in right behind smoking, which the World Health Organization says kills six million people annually.
The research, part of an initiative to monitor the global burden of disease, is being presented at the annual meeting of the American Association for the Advancement of Science in Washington.
Air pollution is composed of fine particulate matter from power generation, transportation, and open burning.
Household pollution is created by stoves that burn coal, wood and animal dung for cooking and heat, primarily in India and Africa. Both can lead to heart attacks and strokes, and the researchers found that nearly one million people die annually from these causes in China, more than a half-million die in India, and nearly 300,000 die in the United States and European Union countries.
Although the report used 2013 data, coauthor Dan Greenbaum, president of the nonprofit Health Effects Institute in Boston, noted that "these things don't change overnight." Last year's death toll likely was similar, he said.
The Chinese government is moving aggressively to improve air quality by forcing automobiles there to be equipped with cleaner technology, and power plants to lower the amount of particulates they spew. But gains are offset by the country's drive to become a world economic power - through the very industries it seeks to better regulate.
The United States, where yearly deaths from air pollution fell from 119,000 to 79,000 between 1990 and 2013, and the European Union, where they fell from 350,000 to 218,000 over the same period, stand as models for China, Greenbaum said. The United States continues to push for lower emissions from automobile traffic and has imposed stronger rules on industry, such as cement plants and those that generate electricity from coal.
China's worsening air pollution is a problem far beyond its borders, with previous studies showing that it marginally increases air pollution on the U.S. West Coast.
At the AAAS meeting, Greenbaum said, a Chinese scientist is set to present an analysis showing that "coal is by far the largest health burden, about 50 percent of the problem."
Report coauthor Qiao Ma, a doctoral student at the School of Environment at Tsinghua University in Beijing, found that outdoor air pollution from coal contributed to about 366,000 Chinese deaths in 2013.
According to her projection, between 990,000 and 1.3 million people there will lose their lives prematurely by 2030 unless ambitious pollution-reduction targets are introduced.