Delhi and air pollution become almost synonymous as winter sets in. Recently, post-Diwali, for instance, the Delhi-NCR region recorded an air quality index (AQI) of 499, putting it in the 'severe' category, according to the Ministry of Earth Science's air quality monitor, System of Air Quality and Weather Forecasting And Research (SAFAR).
However, while we focus on the AQI measuring outdoor pollution, we often ignore another killer: indoor air pollution. "When it comes to indoor air quality, we need to understand that the air indoors is no imported air—it's the same outdoor air which comes inside. So indoor air is almost the same or sometimes more polluted than outdoor air," says Dr Shivanshu Goyal, Consultant Respiratory/ Pulmonology & Sleep Medicine, Gurgaon. Moreover, various substances add to indoor air pollution apart from outdoor pollution coming inside—such as volatile organic compound (VOC), scented detergents, cleansers etc. The worst contributors are dhoop/agarbattis as well as smoking while indoors. It is a known fact that if you smoke inside the house, your house smokes back at you. This means that the soot of smoke gets deposited over surfaces and result in third-hand smoking, which leads to asthma and even pneumonia," he adds.
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Indoor air quality has been a tremendous concern as it affects people's mindset and health. The bad air quality causes various issues such as breathing problems, lethargy, pain in the eyes, and other long-term illnesses. According to a September 2021 study by WHO, 3.8 million people died prematurely from illness attributable to household air pollution.
Senior citizens are the most vulnerable; however, children and adults are also at risk. Noida resident Gaurav Dwivedi had to rush to the doctor one winter night with his child suffering from breathing trouble. He was surprised when the doctor said that poor indoor air quality because of the lack of clean, fresh air into buildings is the cause. "When there is lack of ventilation in our homes, the same stale air re-circulates and indoor pollutants build up. When the outside air quality itself deteriorates in the winter months of November, December and January, this becomes a further challenge to maintain acceptable indoor air standards," the paediatrician told Dwivedi.
The additional hazardous particle load in the air from simple activities like smoking or room fresheners, paints, polishes and furnishings, carpets, fragrances, mould, bacteria, and more can become a significant threat to our health. Experts say indoor pollution levels can be up to 10 times higher than outdoor air pollution. "As people spend most of their time in indoor environments, especially in the backdrop of the pandemic, indoor pollution has become a major health issue. We can improve indoor air quality by deploying re-circulating type air purifiers. However, these reduce the particulates only down to a certain level and have limited effectiveness," says Varun Pahwa, President, Desiccant Rotors International (DRI), a global provider of products and systems for energy recovery, Indoor Air Quality, fresh air treatment, evaporative cooling, green buildings, dehumidification and pollution control. He adds that the best solution to indoor air pollution is dilution using clean outside fresh air even in winter.
While the use of commercial air purifiers is rising, a recent October study led by MIT researchers and professor of civil and environmental engineering and chemical engineering Jesse Kroll and colleagues found that consumer-grade air cleaners that promise to reduce indoor levels of VOC pollutants can ironically be a source of VOCs themselves, thanks to the various chemicals they use.
Dr Goyal advises remedial measures such as planting more trees and even cultivating a lawn in your vicinity to prevent free dust from entering your house. "Avoid dry dusting, as it tends to make the dust settle on the walls; resort to wet mopping or vacuuming. Avoid using dhoop etc, for puja as it emits enormous amounts of smoke. Strong detergents, paints, varnish, etc. are all to be limited as far as possible. Instead, use indoor air purifying plants. Also, the use of indoor air purifiers can be an option," he says, adding, however, that their benefits appear to be limited. He adds that when buying a purifier, there should be no ioniser in the machine. Also, HEPA filters are recommended, and they should be regularly serviced and cleaned.
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Dwivedi's six-year-old son is now doing well. He says, "While we try to get the best external support to address indoor pollution, the paediatrician told me that there is no match to adequate hydration of body along with proper nutrition. I'm trying to cultivate a garden and have also introduced indoor plants. I have also made it a point not to smoke when inside the house." he says.