‘If you can afford it, leave Delhi for 6-8 weeks’: Top pulmonologist as thick pollution haze hangs over city

Air pollution has both short-term and long-term effects on our lungs – and also on other systems of the body. Among children, air pollution leads to diminished growth of lungs, as has been shown by a study conducted at AIIMS. A higher incidence of asthma is also seen among children – about a third in this region, compared to the 5-10% in the rest of the country.

Among adults, 30 or 40 years ago, in 90% of cases of chronic obstructive pulmonary disease (COPD), the culprit was smoking or the use of tobacco. Now, as much as 50% of COPD cases are the result of indoor and outdoor air pollution. Again, more than 80% of lung cancer cases were earlier caused by tobacco smoking; today, in daily data, 40% of lung cancers are seen in people who have never smoked. Also, the incidence of lung cancer is rising among younger patients.

In the long term, air pollution affects the lungs in totality – lung capacity and lung immunity go down. Anecdotally speaking, in my hospital, at least 50% patients of chronic lung disease are usually stable on medication, and do not require oxygen; but in the last five days, the condition of these patients has deteriorated, some have required oxygen, and three have had to be admitted to the Intensive Care Unit (ICU).

A Chicago study involving lakhs of patients that was published in 2023 said that the average lifespan of Indians is reduced by 5.3 years, and average lifespan of Delhiites is reduced by 11.9 years. (This data was part of the updated Air Quality Life Index (AQLI) released by the Energy Policy Institute at the University of Chicago (EPIC) in August 2023. AQLI measures the impact of particulate pollution on life expectancy, and the report drew on particulate matter data from 2021. India was the second worst hit country after Bangladesh, and the report estimated that besides Delhi, air pollution was shortening lifespans by 11.3 years, 11.2 years, 10.8 years, and 10.7 years in Noida, Gurgaon, Faridabad, and Ghaziabad respectively.)

Please note that air pollution not only affects our lungs, but also other systems like the heart, brain, kidneys, intestines, the endocrine system, and immunity at large. There is an increased incidence of heart attacks and brain attacks, and there is more hypertension and diabetes. There is some evidence that even rheumatological diseases like rheumatoid arthritis are more severe.

In the days after Diwali (October 20) I have seen two types of patients.

One, like this otherwise healthy woman patient of age 28 years, who came with a runny nose, sore throat, cough, pain and tightness in the chest, but without a fever. These patients have elevated Fractional Exhaled Nitric Oxide (FeNO) values, which indicates airway inflammation, and they do not respond to antibiotics – they respond only to steroids, corticosteroids. Sometimes I have to give them inhalers. Two, people who have asthma or COPD or other types of chronic lung disease – they have come with severe attacks. And there have been more patients requiring hospital admission and ICU admission.

The impact of air pollution on lung disease was demonstrated during the Covid-19 pandemic. Northern Italy is more polluted compared to southern Italy, and Covid mortality was higher in northern Italy. Similar patterns were seen in Germany. So, there is evidence that air pollution leads to severe forms of pneumonia, be it viral or bacterial, leading to high mortality.

What can people do to protect themselves from air pollution while living in a city like Delhi?

Everybody cannot afford to leave Delhi, because it is not simple. But those who have chronic lung disease or chronic heart disease, those who are on oxygen, and those who have the opportunity and ability to go abroad or to less polluted places, I very safely advise them to leave Delhi for 6-8 weeks from now, so as to protect themselves from the distress of breathlessness, the requirement of oxygen, and so on and so forth.

I have been in Delhi for 40 years myself, I have grown up as a doctor at AIIMS, I was there for 30 years. I had a family to look after, and so I continued. Not that I did not know the danger – the first study we conducted on air pollution was in 1997!

But my children and my grandchildren have the choice to relocate, and I have never advised them to come to Delhi-NCR.

How does particulate matter (PM) and specific types of gases impact a person?

Particles that are larger than 10 microns in diameter, do not travel beyond the upper airways. They do not cross our noses, which filter out these particles. Particles that have a diameter of 10 micrometres or less, that is PM10, cause cough, tightness of the chest, irritation, and some mucus. PM2.5 are particles that go to the lowest part of the lung, the alveoli, where the exchange of gases takes place. These particles are the most harmful.

But what is not talked about routinely is the nanoparticles, ultrafine particulate matter of less than 0.1 micron size. These particles are measured only as research tools – but they cross the airways and alveoli and go inside the blood, and then travel all over the body, to the brain, the heart, kidneys, and intestines.

Gases such as carbon monoxide, nitric oxide, and sulphur dioxide easily cross the lungs and go into the blood vessels. Carbon monoxide has no odour and causes no cough. It goes into the bloodstream and reduces the oxygen-carrying capacity of the blood, leading to more heart attacks. Sulphur dioxide and nitric oxide cause severe bronchitis and lung diseases.

How helpful are air purifiers in this situation?

Air purifiers have a filter, and good air purifiers have an adsorbent which is expected to adsorb gases [by creating an adsorbate film on the surface that holds back molecules], so that the air that comes out is likely to be clean. An air purifier of good quality and capacity should cover the volume of the room. It should be on all the time. The device should be close to, and should face the person using it, so that the clean air comes directly. Most importantly, the room has to be closed all the time – its effect is nullified if the door is opened multiple times for people to come in and go out.

The World Health Organisation (WHO), of which I am a member, does not agree that air purifiers lead to an improvement in health. But my recommendation is that for those who are elderly, or have chronic heart disease, COPD, and other lung diseases, and who stay at home, an air purifier would be helpful.

Dr Gopi Chand Khilnani is Chairman, PSRI Institute of Pulmonary, Critical Care, and Sleep Medicine. He was Formerly Professor and Head of Pulmonary, Critical Care and Sleep Medicine at AIIMS, New Delhi.