Delhi’s air pollution is a public health emergency, so why aren’t more people wearing masks?
Properly-fitting masks have been shown to dramatically reduce exposure to air pollution and to improve markers of respiratory health. And yet, few people in Delhi wear protective masks, even when travelling through heavily polluted areas.
Although the idea of distributing masks isn’t uncommon, the scale of Delhi’s effort is globally unprecedented.
– By Kenneth Lee, Michael Greenstone, Patrick Baylis and Harshil Sahai
The residents of Delhi are officially living through a public health emergency. Dangerously high levels of PM 2.5, which have exceeded 400 micrograms per cubic meter in the city in recent days, can lead to a host of deadly cardiovascular and respiratory illnesses. These impacts will be experienced across much of India. According to the Air Quality Life Index (AQLI), the life expectancy of the average person in the Indo-Gangetic Plain region of India would be 7.1 years higher if air pollution levels were permanently reduced to meet the globally accepted standard.
In response to this emergency, the Delhi government has launched a massive campaign to distribute 5 million protective masks to its citizens. Although the idea of distributing masks isn’t uncommon, the scale of Delhi’s effort is globally unprecedented. As researchers who study how people defend themselves from air pollution, we have one question: what will this accomplish?
Properly-fitting masks have been shown to dramatically reduce exposure to air pollution and to improve markers of respiratory health. And yet, few people in Delhi wear protective masks, even when travelling through heavily polluted areas. In contrast, masks are a common sight in major cities in countries like China and South Korea, even when pollution levels are just a fraction of the levels typically encountered in Northern India.
Our ongoing work suggests that this is due to two factors: first, awareness about the harmful effects of air pollution is still relatively low; and second, there may be social norms that discourage people from adopting and using their masks. For these reasons, placing masks in the hands of millions – particularly during a public health emergency – might alter the way people think about and defend themselves from air pollution, both today and tomorrow.
Our perspective is informed by emerging experimental research work we have been carrying out through the Energy Policy Institute at the University of Chicago in India (EPIC India). Last year, during the peak pollution season, we interviewed nearly 3,500 individuals living among the large population of Delhi slums, in order to understand how air pollution pervades daily life.
In our data, three patterns stand out. First, in the majority of Delhi’s poorest households, concentrations of PM 2.5 inside a home were nearly as high as those outside a home. Polluted air easily seeps into households through cracks under doors, poorly sealed windows, and the ventilation units built into the walls of typical kitchens.
Wealthier households are able to avoid the outdoors, commute in air-conditioned vehicles, work in offices, and invest in air purifiers. Many of these luxuries are simply inaccessible for poor households. In other words, air pollution is likely to impact the poorest citizens the most. At the same time, given that these individuals are facing such high levels of indoor air pollution, handing out masks may not achieve much.
Second, providing people with information about the detrimental health effects of air pollution increases the likelihood they will purchase a pollution mask. In our experiment, we offered pollution masks at various discounted prices. Even at a 50 per cent discount, less than 1 in 10 residents purchased a mask for Rs 50. However, people were more likely to purchase a mask if we showed them a simple, two-minute educational video about air pollution.
Third, there may be social determinants that prevent people from adopting protective masks. In our survey data, a substantial share of respondents admitted that they thought people who wore masks looked strange. Subsequent usage rates were also low.
In the face of these barriers to mask adoption, what can be done? It’s possible that the Delhi government’s big push to promote and distribute masks will help improve awareness, and this will, in turn, reduce this social stigma. But greater awareness may have benefits that will stretch beyond simply wearing masks.
Looking abroad, Beijing has achieved an extraordinary decline in its air pollution in recent years: PM 2.5 decreased by 35 per cent between 2013 and 2017. This was possible because a better-informed citizenry began to demand cleaner air. Clearly, the Delhi government is taking bold actions to address this emergency period. But the focus must remain on permanent reductions in air pollution. This would yield health benefits that are far greater than anything that could be achieved through pollution masks alone. Perhaps the most important achievement of handing out millions of masks will be to raise pollution awareness. Simply put, this is what it will take to motivate large-scale actions to clean the air.
(Ken Lee is an Executive Director at the Energy Policy Institute at the University of Chicago (EPIC-India). Michael Greenstone is the Milton Friedman Distinguished Service Professor in Economics at the University of Chicago and Director of EPIC. Patrick Baylis is an Assistant Professor at the Vancouver School of Economics at the University of British Columbia and Harshil Sahai a PhD student at the University of Chicago)
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