A new paper has added to the growing body of research indicating that India’s air pollution has become a matter of life and death. The study, published this week in the journal Geophysical Research Letters, suggests that outdoor air pollution in the country is contributing to more than half a million premature deaths each year at the cost of hundreds of billions of dollars.
The deadly power of air pollution is no new finding. Numerous studies have concluded that both outdoor and indoor pollution can cause a variety of serious diseases, including ischemic heart disease, chronic pulmonary obstructive disease, increased risk of stroke and even lung cancer. One study published last year in Nature, for instance, estimated that a type of pollution known as “fine particulate matter” — tiny toxic particles that can be released by a variety of sources, including the burning of fossil fuels or organic matter — is responsible for about 3 million deaths worldwide each year.
In certain parts of the world, particularly India and China, air pollution is an ever-growing public health concern. This may be especially true for India, which reportedly surpassed China earlier this year in the overall amount of fine particulate matter pollution its citizens are exposed to. That report, which was published in February by Greenpeace, found that fine particulate matter levels in New Delhi came to about 128 micrograms per cubic meter, in comparison to Beijing’s 81 and Washington D.C.’s 12. In contrast, theWorld Health Organization recommends that nations shoot for an annual average of 10 micrograms per cubic meter.
The authors of this week’s paper have pointed out that most studies that model pollution-related mortality have focused on Europe and the United States, with comparatively few studies on mostly urban areas in India. A few broad studies have attempted to produce estimates for the globe as a whole, including regional estimates for India or South Asia — these included two independent 2015 studies and a 2014 World Health Organization report, all of which suggested that pollution-related premature deaths were above 0.5 or 0.6 million annually.
The new study, which focuses specifically on India, further supports those estimates. The study relied on computer simulations of outdoor air pollution levels throughout the nation — including both fine particulate matter and ozone, which is also known to cause respiratory disease — using data from national inventories on pollutant emissions. The researchers then used a model (relying on previous research on the human health response to pollution exposure) to estimate the number of associated premature deaths. All the simulations were based on 2011 data.
Their results suggested that about 570,000 premature deaths in India were caused by exposure to fine particulate matter in 2011, and an additional 12,000 were caused by exposure to ozone. The most severely affected part of the country was the Indo-Gangetic region, which includes the northern strip of the country.
“[It’s] good to see that the results from this study are in good agreement with our work, which shows that these numbers are quite robust, and that air pollution is indeed an important cause of premature death,” said Jos Lelieveld of the Max Planck Institute for Chemistry in Germany, who led one of the 2015 global studies on pollution and premature mortality. Lelieveld was not involved with the new study.