delhi

Updated: Oct 31, 2019 21:04 IST

As Delhi battles severe pollution levels, Dr Randeep Guleria, director, AIIMS, speaks to Hindustan Times about the health effects of bad air, how we can keep ourselves safe and if masks and air purifiers really work.

How does air pollution affect health?

Air pollution mainly affects the lungs but more and more data shows it affects the entire body. We have poor quality air for most days of the year in Delhi or the Indo-Gangetic belt. So what happens to people who are breathing poor quality air for more than 10 years? Apart from lung cancer, it causes inflammation in the blood vessels running through the lungs and the rest of the body. It leads to atherosclerosis or the hardening of the arteries, which predisposes people to heart attacks and stroke. Cardiac associations now say living in areas with higher levels of air pollution is as much a risk of heart attack as is smoking. All of us who have been living in Delhi for long are adding to our risk of heart attack and heart disease.

The short-term effects of air pollution are predominantly seen in people at high risk. Inhaling toxic substances – it could be oxides of nitrogen, sulphur dioxide, particulate matter – causes worsening of underlying bronchitis, asthma and heart disease, leading on to heart failure or respiratory failure, which leads to emergency visits, more medication need, and overall higher morbidity and mortality.

Do more patients get admitted to hospitals?

Yes. In a recent study, we looked at hospital emergency room visits both in the paediatric and adult age group throughout the year and found a direct correlation in a spike in patients with cardiac and respiratory problems in the 72 hours following air quality deterioration.

Dr Randeep Guleria currently serves as director of AIIMS. ( HT Photo )

Does poor air pollution raise the risk of infections such as tuberculosis, influenza and pneumonia?

Yes. There is some data that suggests chances of infection also go up.

Should parents keep children indoors when air quality is bad?

Very often, we get letters from school principals, asking whether they should stop outdoor activities during winter. You have to balance things out as outdoor activities are good for children but unhealthy air is not. When you have high levels of air pollution, outdoor physical activity should be restricted. You should wait for the sun come out and to at least for the pollutants rise up. But is a big challenge– should you move to indoor activity? Should you use air purifiers? Those are the type of things that a lot of schools ask.

The solution lies in finding a permanent sustainable way out so that air quality improves throughout the year and continues to do so over the years. We should consider what should we do to encourage people to use public transport, become more eco-friendly, walk if they can rather than taking a vehicle, children use car pooling or school bus to go to school rather than everyone using individual cars. One study showed AQI is very bad around most school entrances when school starts and when it gets over because many vehicles are parked out there with their engines running. Children who come out or go to school at that time are actually breathing in very toxic air.

Do masks and respirators work?

Masks are something that we don’t routinely recommend, though if high-risk patients want to use one, we ask them to use a three-layered surgical mask or an N-95 mask worn tightly around the nose and mouth. If it’s loosely worn, you create a negative pressure when you inhale and air gets sucked in from the side instead of the filter. Then the mask is of no use. You have to have a mask that is tightly fitted, which causes discomfort. Among other things are nasal filters, but these are useful for people who are at high risk or going to areas where pollution level is very high.

There is not enough data to say that it helps in the long run for everyone to wear a mask. It gives a little bit of reassurance but it does it really decrease exposure and does it protect you? I think for that we need a larger policy and a bigger plan rather than just wearing a mask.

It may actually increase exposure because you think you’re protected when you’re not.

Exactly. It gives you a false sense of security.

Do you recommend air purifiers? Do they work?

Most of the data for air purifiers looked at a room that is properly sealed and the person is in that room for most of the day. Most of our rooms are not properly sealed, with air and dust entering from the windows and doors. Air purifiers are not that effective, and you’re going in and out (of the room with the air purifier). Again, like masks, it may give you a little bit of reassurance but overall, I don’t think it is not a solution.

Can our lungs adapt to change?

There is a limit to what the body can adjust to. We have a reserve that stops you from becoming breathless when your lung capacity falls to some extent. But when that reserve goes as you age, the chances of getting respiratory problem become higher. So it will cause problems in later life, it may not cause that much of a problem in the younger age group.

Should people exercise when the air quality is severe or very severe?

Not aggressive exercise, not outdoor exercise. Not early in the morning, but maybe around lunch time when the sun is out. You should continue to exercise -- the benefits of exercise are much more -- but in an environment that is not as bad as what you are saying.

(Dr Randeep Guleria is a professor and the head of pulmonary medicine and sleep disorders at the All India Institute of Medical Sciences and one of the world’s foremost experts on lung health )