‘You See 999—Maxing Out the Air Pollution Monitors’.
In early November, smog in Delhi was so thick that flights were cancelled, cars crashed and piled up, and schools were closed. “Delhi has become a gas chamber,” tweeted the city’s chief minister, Arvind Kerjriwal. Arvind Kumar, chairman for chest surgery at Sir Ganga Ram Hospital, told Reuters that breathing the Delhi air during the worst days of smog was the equivalent of smoking 50 cigarettes a day.
This year’s smog is not a one-off event, says Kevin Lane (SPH’14), assistant professor of environmental health. “We’re seeing these large-scale air pollution smog events that are reminiscent of the London Smog in 1952 and Donora, Pennsylvania, in 1948,” he says. “They’re reoccurring. They were in China, and now they’re occurring yearly in India.”
While the immediate effects of the smog in Delhi were dramatic, Lane says, the recent crisis is part of a much larger issue, with high levels of air pollution throughout the country. In the 2015 Global Burden of Disease analysis, ambient air pollution was the fifth-largest factor contributing to mortality in lower- and middle-income countries, contributing to 1.81 million deaths annually in India and 6.5 million globally. “That’s about three times what you would see for communicable disease deaths from AIDS, tuberculosis, and malaria combined” Lane says.
Lane discussed his work in India, the nature of the problem, and what policies India will need to enact.
What led you to study air pollution in India?
I’ve specialized in air pollution and urban exposures for about 10 years, going back to when I was a doctoral student here at SPH. Originally I focused on Boston, but I was really drawn to work internationally, especially with what is going on in Asia.
India is undergoing rapid urbanization and seeing significant increases in both air pollution and health effects like cardiovascular disease. They’re transitioning from a lower-middle income country economy while expanding their urban population, and simultaneously transitioning from communicable to non-communicable diseases, so these rapid changes are not just affecting the economic development of the country, but citizens’ health as well.
There’s a potential to not only analyze these health outcomes, but to also help researchers on the ground gather evidence to support political changes and policy solutions that we’ve instituted in places like the US, and that China is now also looking to implement. There’s potential here to not only conduct research, but to see actual lives saved.
How bad is air quality in India now?
In Delhi, we’re talking about exposure during these smog events that could be anywhere between 500 and approximately 1,000 micrograms per cubic meter—maxing out the air monitors—of particulate matter size 2.5 (PM2.5), one of the air pollutants significantly associated with cardiovascular and respiratory mortality. During those events on November 7 this year and in 2016, both exceeded the maximum capacity at the US embassy’s monitor to measure PM2.5. You saw “999,” and that means it’s in excess of what the monitors can read. These are really large exposures, and from a health perspective these are alarming and unsafe levels.
When people talk about air pollution in India, they’re really drawn to Delhi, especially because of these massive smog events. But if you look at the country overall, the levels that we’re seeing in what would be considered some of the “lower exposure areas,” like the area where I’m working in Tamil Nadu in southern India, have an annual average exposure range that is between 25 and 38 micrograms per cubic meter of PM2.5. That’s still very high compared to most major urban areas in the US and Western Europe. It’s double what we would consider to be the standard here in the US.
Why are these smog events occurring in Delhi around November 7?
Delhi sees increases in air pollution in late October and early November, from a combination of Diwali—the festival of lights in which people light a lot of firecrackers and fireworks—and simultaneously crop burning to clear fields in states to the west and north of Delhi. There are also local traffic and indoor sources of air pollution, which are pretty massive. You can still be burning diesel, kerosene, coal, or even wood to heat your home and to cook. Due to atmospheric conditions that occur more readily in the late fall and winter, you can end up with a capping of air pollution due to an inversion in the atmosphere. Also, if you don’t have a lot of wind movement or precipitation, then air pollution can build up over a number of days to these massive, catastrophic smog events.
What is the focus of your current work in India?
There’s a large amount of evidence from studies in North America, Europe, and increasingly in China, showing that particulate matter—especially chronic exposure fine particulate matter like PM2.5—leads to both cardiovascular and respiratory disease. However, when you want to create policies for a different country, you want some localized data. By collaborating with researchers in-country and helping them develop air pollution models that can be associated with their health studies, their mortality information, and their own study cohorts, we can aid these groups in their efforts to provide local evidence to support policies.
This past August, I went on a trip to the Indian Institute of Public Health in Ganhindagar, in the state of Gujarat, as part of a research group led by Joel Schwartz at Harvard T.H. Chan School of Public Health. We’re trying to develop a nationwide air pollution model, and we’re actually using similar models on health research here in the Department of Environmental Health through the Center for Research on Environmental Social Stressors in Housing Across the Life Course (CRESSH), which is a collaboration between SPH and Harvard.
I was invited to India as a guest researcher to discuss geographic information system (GIS) infrastructure, incorporating satellite data into the development of a new air pollution model, and then applying the exposure data to different cohort studies. The goal of the visit was to provide researchers with the training and the background, and then to develop a collaborative consortium with goals and assignments to build these air pollution models, and to have them be run by local researchers at the Indian Institutes of Technology and at the Public Health Foundation of India. We’re now setting up a more long-term collaboration, to move this forward as quickly as possible.
I’ve also been collaborating since my doctoral studies with researchers from Sri Ramachandra University in Chennai and Tufts University to examine the association between air pollution, built environment, and cardiovascular disease progression in an 8,000-person adult cohort. So far in these rapidly urbanizing areas like Chennai we’ve seen significant associations with blood pressure and other cardiovascular measures that are two or three times the observed effects in similar US cohort studies.
What policies can India enact to improve its air quality?
One is through fuel switching, having people no longer use solid fuel sources by providing liquid petroleum gas. That’s still going to be giving off air pollution, but not nearly the same amount of particulates. Part of the work I’m doing with Tufts and Sri Ramachandra University is working with the Global Alliance for Clean Cookstoves initiative, examining whether these fuel changeovers are effective in Chennai and in rural Tamil Nadu, to provide some local evidence of whether this policy initiative can successfully reduce indoor and ambient PM2.5.
Some of the larger-scale policies that India or the city governments could consider are improving vehicle and stationary source emission standards for long term reduction. Also, during these smog events there’s been discussion about different driving days, where odd-numbered cars drive on certain days and even-numbered cars drive on other days—although these policies can receive enough backlash to stop them from being enacted. There’s also the idea of stopping construction for a series of days to allow the ambient air pollution to dissipate, but that’s lost wages and lost income.
There are tradeoffs that need to occur, but India could reduce the pollution levels in their national air quality standards, and begin to institute mechanisms to reduce pollution on a large scale. There are excellent researchers in India working to provide the local evidence to support those standards, and as public health scientists we can and should assist them.