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The Road to Cleaner Air

Rashid Shaikh explains the health impacts of air pollution and how Indian cities can improve their air quality.

Rashid Shaikh is the director of science at the Health Effects Institute in Boston, Massachusetts, where he is responsible for the management and oversight of the institute’s diverse research portfolio and review activities. Previously, Shaikh was the director of programs at the New York Academy of Sciences, where he managed the academy’s meetings program and launched several activities focused on cutting-edge research. He received his bachelor’s degree from St. Xavier’s College in Mumbai and his master’s degree from Indian Institute of Technology, Kanpur. Shaikh has a doctorate from the Massachusetts Institute of Technology, and has worked at Harvard Medical School and Harvard School of Public Health.

He visited New Delhi and Chennai in November 2015, where he interacted with air quality and health researchers, government officials, students of environmental studies and sustainable development, doctors, medical students, activists, non-governmental organizations and journalists.

Excerpts from an interview.


Please give a brief overview of your work at the Health Effects Institute.

The Health Effects Institute (HEI) is a not-for-profit, public-private partnership that delivers sound and impartial science about air pollution and its effects on health. HEI has a unique, leveraged funding and governance structure—with joint funding from the U.S. Environmental Protection Agency (EPA) and the worldwide automotive industry—and it has provided the scientific underpinnings for many areas of air quality standards and policy, though HEI itself does not make policy recommendations.

HEI focuses on air pollution and health, and sponsors research at universities and research institutions in the U.S. and abroad. Its work also encompasses research on the assessment of exposure to air pollutants and air quality. HEI has made important contributions to the study of the health effects of particulate matter and has worked on ozone, nitrogen oxides, air toxics and other pollutants. Its focus includes traffic-related air pollution as well as accountability studies which investigate the impact of regulations on air pollution levels and their impact on public health. HEI reports, which communicate HEI findings and commentaries on them, are available on its website for free.


What are the main sources of outdoor pollution in India and their potential health impacts?

There are multiple sources of outdoor air pollution in India, such as power plants that use coal, industrial activities, the transportation sector, diesel generators, brick kilns, biomass burning, construction activities and road dust.

In terms of the health effects of pollutants from these sources, we have very good scientific evidence that both short- and long-term exposure to airborne pollutants harms human health. Indeed, exposure to outdoor air pollution is among the top factors in shortening people’s lives—it is estimated to cause some three million premature deaths around the world each year, approximately 625,000 of them in India.

The largest risk of air pollution comes from particulate matter which is emitted from a variety of sources. Exposure can lead to asthma in children and affect respiratory health in children and adults. But, by far, the greatest risk is to the cardiovascular system. We have extensive evidence that particulate matter exposure leads to heart disease and stroke. Exposure to particulate matter can also lead to cancer, chronic obstructive pulmonary disease (COPD) and diabetes, besides other conditions. Indians are well known to be particularly prone to cardiovascular disease and diabetes, so we should pay special attention to particulate matter exposure.

Oxides of nitrogen and sulfur, sulfates and a variety of volatile organic compounds are among the other air pollutants emitted from the sources mentioned above. Some of these chemicals interact with each other and form ozone, secondary aerosols and smog. Exposure to these agents is associated with many adverse health effects, including cardiovascular effects and premature mortality, airway inflammation, reduced lung function (particularly in children and in people with asthma) and other respiratory conditions. There is also increasing evidence that air pollution exposure affects the nervous system as well as pregnancy outcomes.


What are some of the immediate, easy steps that Indian cities can adopt to improve air quality? What are the more long-term policies they should implement for cleaner air?

Since air pollutants are emitted from many sources and diverse activities, multiple approaches are needed to control them. However, after the needed controls for any of the sources are put in place, it can take some time—often many years—for policy actions to show their full benefits.

The Indian government has recently taken several steps forward. First, it decided to advance the adoption of Bharat VI emission standards (equivalent to Euro VI and similar to US 2010) for diesel vehicles starting 2020, leapfrogging over the Bharat V standards. This move will be preceded by the action to bring ultra-low-sulfur diesel fuel to the market by 2020, which is needed to meet the new standards. Vehicles complying with the Bharat VI standard are equipped with sophisticated engine controls, as well as filters to eliminate particulate matter emissions and other devices to control the emission of nitrogen oxides. Moreover, the use of ultra-low-sulfur fuel will also reduce particulate matter emissions from traditional, older diesel vehicles.

Second, the Ministry of Environment, Forest and Climate Change has updated the emissions standards for thermal power plants. The new standards place limits on the emissions of sulfur dioxide, nitrogen oxides and mercury, and make the existing standard for particulate matter significantly stricter. These rules will bring the emissions standards for Indian power plants close to those in other developed and emerging economies. The standards will become effective for both new and existing plants by about 2017. Given that thermal power plants are estimated to contribute 15 to 20 percent of the air pollution in Delhi, this is another highly welcome development and should result in substantial public health benefits.

The government can also take steps to curb air pollution from other sources like industrial units. Mobile-source air pollution can be reduced by traffic management measures, such as the recent and much debated scheme of odd-even driving in Delhi. There are ample other experiments that may be tried. For example, congestion charging schemes can provide economic incentives to drivers and have been implemented in many cities, including London and Singapore. We can also try to manage vehicular movement more efficiently on roads, by enforcing simple traffic rules like drivers staying in one lane, using only one lane to make a turn, keeping slower traffic on the left and faster traffic on the right, synchronization of traffic signals, etc. Such actions can improve traffic flow and manage congestion, thereby also reducing air pollution.

The really big challenge in India is the management of emissions sources that are widely dispersed and are a part of people’s daily lives, like biomass burning for cooking and keeping warm. Agricultural burning and brick kilns are other challenges. But there are approaches that may control such sources also. For example, the use of alternative fuels, such as LPG, can significantly reduce emissions from cookstoves.


Besides sources of emissions, what other factors should policymakers keep in mind while developing air pollution regulations?

In some instances, policymakers can mandate a change in the fuel used for activities such as power generation, transportation and home cooking. In other cases, behavioral changes like use of public transportation, traffic management and mobility improvements can reduce air pollution.

I am often told that pollution control is costly and growth is a higher priority for a country like India. Of course, there is a cost associated with air pollution control. However, when air pollution is not controlled, the polluters, whoever they are, dump pollution into the air at no cost to them. The cost is borne by people, whose health suffers and by society, when the environment degrades and when it has to pay for treating the sick. Once controls are mandated, the cost is paid by the consumer (e.g., by purchasing a less polluting vehicle), by the industry (e.g., for installing emission control devices), or by society (e.g., for providing public transportation). Despite the costs, several studies have shown the net benefit of controlling air pollution, over a reasonable period of time.


Based on your recent visit to India, can you give examples of some U.S. best practices that would be relevant for Indian cities to control air pollution?

In principle, many of the examples I have discussed can be useful in India. However, important differences related to national priorities, legal and legislative framework, availability of resources, and technical know-how and capacity, should be kept in mind.

Regarding prevention of air pollution from transportation, in addition to the kinds of actions discussed above, another important factor is a broader approach to “mobility.” Good mobility policies comprise a combination of private and public transportation, locations of housing, workplace, schools, shopping and entertainment, as well as green space, to name just a few. So, mobility represents a comprehensive approach to economic and social development, because these issues and problems are all inter-connected and need to be addressed in concert.

Finally, there are myriad details in the ways in which policies have been developed and implemented in industrialized countries. India can take lessons from such efforts but, ultimately, a set of solutions designed to suit Indian needs will need to be developed. And, we see this beginning to happen.


Do good air pollution regulations lead to improvement in health? Are there demonstrated examples?

Surely. There are many examples of this, but let me give just a couple. In an early study, Dr. Arden Pope of Brigham Young University reported that during the winter of 1987, when a steel mill in Utah—the largest source of air pollution in that area—was closed due to a strike, two-thirds fewer children were hospitalized with lung ailments than in the year before. After the strike, the steel mill resumed its operations and the hospitalization rate went up again. Although this study was not looking at the impact of regulation, it clearly showed an association between a reduction in air pollution levels and improvement in children’s health.

In another example, the Chinese government took unprecedented steps to reduce air pollution during the 2008 Olympics in Beijing: it ordered factories in the region to be closed and very tightly controlled vehicular traffic. The ambient levels of fine particles (PM2.5), sulfur dioxide and nitrogen oxides, but not ozone, went down in Beijing. Dr. Jim Zhang, supported in part by a grant from HEI, followed a group of medical students before, during and after the Olympics and measured various markers associated with respiratory and systemic health. He found overall improvements in these indicators of health during the Olympics when air was cleaner. But the levels of these indicators were higher both before and after the Olympics when air was dirtier.  

Such studies, I should emphasize, are difficult and complex and must be done very carefully. One has to be careful to parse out the impact of the regulation from other concurrent changes that may also affect air pollution, for example, fluctuations in economic activity, meteorological factors, changes in demographics and socioeconomic status, and access to medical care. HEI has funded many accountability studies and they provide useful examples of how these kinds of studies should be performed.


What are some of the most common questions you were asked by audiences in India and what were your responses?

In addition to the kinds of questions answered above, other common questions I was asked were:

What can I do personally to safeguard my health as well as that of my family?

Air pollution is a society-wide problem and the few measures that you may take personally will hardly solve the problem. In any event, use of air purifiers in homes that are “tight” and preferably air-conditioned can be helpful. Air purifiers with HEPA (high-efficiency particulate air) filters are the best, but the use of air purifiers that include ultraviolet (UV) light should be avoided because some of them generate harmful ozone gas. Ideally, a qualified laboratory should test the air purifiers in the market under real-world conditions to determine their effectiveness. I am not aware that such tests have been performed in India.

Can plants and trees clean up air pollution?

Despite many claims about the effectiveness of plants for making indoor environments clean, I have not seen any reliable and well-conducted studies that support this assertion. It should be noted that plants can be harmed by air pollution, and the U.S. EPA considers deleterious effects on agriculture in its welfare calculations for secondary air quality standards.