Here in India, we are talking about outdoor air quality – smog and PM 2.5, given the current context of cities like Bombay and DelhiWhy should we care about indoor air quality?

Basically, instead of talking about indoor or outdoor separately, we should talk about a single air, since the air we breathe outdoors is the just like the one we breathe that is inside the house. Additionally, it is important to address air as a single entity rather than labeling it as indoor or outdoor because then it can easily be framed as a public health issue. So in a way, we can’t separate the inside air from the outside. We cannot separate these two airs unless we enter a submarine or board a space shuttle, then we will be completely separated from two different types of air, otherwise it is not possible to not be exposed to outside air even if we are indoors. As a result, indoor air quality is just as important as outdoor air quality.

So when talking about an air, how do you really differentiate between indoor and outdoor air?

The best authority here will be the World Health Organization (WHO), which published the first air quality guidelines in 1989 and the second guidelines were published in 2000. The guidelines were subsequently revised in 2005, 2010 and 2021. Thus, in the above guidelines, the pollutants that cause pollution usually originate outside where they are produced and then enter the interior. Later, in the 2010 guidelines, it was listed that there were 14 different pollutants that were specifically emitted indoors. The WHO calls them selected contaminants and those contaminants are not so relevant if we talk about about them in the context of an outdoor environment. So, if we talk about suspended particulate matter (PM), for example, its main sources would be outdoor activities such as combustion, however, these pollutants also enter the interior of a house and gradually the lines of differences become blurred. Therefore, I personally propose a completely different definition of air quality, for me the only air quality is that which promotes and affects health. Any air quality or pollutant that is harmful to our health should be avoided regardless, whether exposed indoors or outdoors.

His research focuses on proper ventilation to achieve the correct AQI standards. What are the effects of ventilation in terms of health recovery based on your research findings?

There are two different types of pollutants in the air: microbiological and gaseous. So if we talk about which is more harmful, then I would say that we have read and learned a lot about PM 2.5 being one of the few dangerous pollutants that are generated outdoors that can harm our health. Therefore, in this context, ventilation is very important as it plays in the dispersion of pollutants from outside air when it travels indoors and if the indoor air is clean the adversity of pollutants is reduced. As a result, ventilation also influences exposure to air quality. So now that indoor air is filtered due to ventilation, direct and indirect health benefits can be felt; Firstly, clean air reduces stress and improves stress levels. This increases people’s productivity. On the contrary, inhalation of pollutants also has powerful effects, but they are not adverse and cannot be felt immediately, as they are much longer term. For example, if you smoke cigarettes, you will not develop lung cancer right away. Similarly, once you start inhaling pollutants, you won’t develop any signs right away, but after about 20 years, you may end up developing Alzheimer’s or dementia or perhaps some lung disease. So in a way, proper ventilation is also an indicator of better air quality.

In the Indian context, when we invest substantially in air quality purifiers, how should we consider this balance between ventilation and air purifier?

We need to ensure minimum ventilation standards, which must be a minimum mark of outdoor air circulating indoors or else we may end up inhaling high levels of carbon dioxide and other forms of pollutants that may have been generated indoors as well. Therefore, we need to modernize solutions in our homes and workplaces with the help of high-efficiency fans and filters so that a minimum standard of air cross ventilation is maintained. In addition, modernized objects must be routinely maintained to ensure that their service delivery remains at the top.

India has seen an increase in air conditioning sales in recent years; The government has also asked manufacturers to set a minimum temperature of 18 degrees. Does this have any role to play in terms of air quality management in India?

First of all, an air conditioner does not clean the air, it removes humidity and lowers the temperature. There are solutions that can be retrofitted to an existing air conditioner and this way the air conditioner can become an air cleaner and you will not need a separate air purifier. In case you have another air purifier within the periphery of the air conditioner, it may affect the overall air distribution. Therefore, the solution is to carry out a modernization. Which means that, on the one hand, you have air conditioning and you can install a purifier that provides the required service.

An air purifier is also very expensive. How can an average low-income group or middle class afford it?

We have equated this analogy with the theory of purchasing a vehicle. The purpose of buying a vehicle is to ensure mobility, some people buy high-end vehicles, some people buy a basic model of any car, while others buy two-wheeled vehicles like scooters or bicycles. Although the mobility service is common in all categories, the quality of the service in terms of comfort level is different in each vehicle. Likewise, there are different types of air purifiers on the market. Some of them are stylish and very expensive, while some products would be affordable but would not look as stylish. But the common function of these products is to ensure the cleanliness of the air.

In your research you mentioned that carbon dioxide is a marker of indoor air pollution. So how is carbon dioxide different from PM 2.5 particles?

So PM 2.5 is particles, while carbon dioxide is a gas. As a result, these two materials will have different effects on our body. Primarily, carbon dioxide is used as a ventilation marker for spaces that do not have a mechanical ventilation system and are filled with people, therefore you will need a separate marker, for which carbon dioxide is used as an alternative marker to identify ventilation levels. Furthermore, the main source of carbon dioxide is human metabolic air, as opposed to particles that are artificially emitted.

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Post-covid people have adapted the habit of wearing masks. Does the use of masks also have side effects?

There is some research that shows that wearing a mask can be harmful to people, so this is a trade-off. But these are mostly for sick people who have some lung problems or respiratory diseases. Even in healthy people, we have seen that masks have affecting physiological effects. But for healthy people, these effects could recover very quickly; However, there are no long-term health effects that may have been caused by wearing masks.

In Mumbai, almost 50 percent of the population resides in slums, in overcrowded situations and many of them are located near polluted areas. According to you, what can be some of the practical measures to protect them from air pollution?

These are extreme conditions and the fact that air quality and pollution are affecting the life expectancy of those living in such situations is a secondary concern. There are issues related to malnutrition, then they have terrible living conditions, bad sleep cycles, sanitation problems. These conditions are much more harmful to them than air pollution. The issue of air pollution will only contribute to these problems. Therefore, eliminating air pollution will not make any big difference. The only big change is to improve your lifestyle and that is how you can bring about changes in your livelihood and improve your life expectancy. For example, in Europe, a part of the population has social difficulties. Therefore, we need to improve their lifestyle and in addition to improving the indoor environment, access to medicines and healthcare is also improved. The indoor environment plays an important role, but so do all other factors.

“Inhaling pollutants also has powerful effects, but they are not adverse and cannot be felt immediately as they are much longer term. For example, if you smoke cigarettes, you will not develop lung cancer right away. Similarly, once you start inhaling pollutants, you will not develop any signs immediately, but after about 20 years, you may end up developing Alzheimer’s or dementia or perhaps some lung disease.”