Air quality in large parts of north India, including Delhi, was in the “severe” category for most of this week, improving briefly to “very poor”. One question not only made headlines but filled social media timelines: Why does Delhi have toxic air every winter?
That question, though valid, misses another important point. Air pollution is a year-round problem in India, not just Delhi.
Even the country’s “cleanest air” days, usually observed during the monsoon, are now generally above the World Health Organisation’s advised levels of fine particulate matter 24-hour mean (which is around 25 micrograms per cubic metre).
And even if you try to limit outdoor exposure during these high-pollution months, danger still lurks in homes, regardless of where you stay. Research has shown that prolonged exposure to indoor air pollution can be extremely harmful—in both rural and urban homes. So you may need to invest in air purifiers regardless of the air quality outside.
Household air pollution caused by the burning of solid fuels is still common in rural areas, though the State Of Global Air Report 2020 shows the number of deaths attributable to household air pollution is on the decline.
Air in urban homes isn’t safe either. For one, ambient air pollution finds its way in. But that’s not all. “Indoor air quality is a representation of the outdoor air. But the air inside can worsen further depending on the activities being done in the house,” says J.C. Suri, director and head of department, pulmonology, critical care and sleep medicine, at the Vasant Kunj-based Fortis Hospital in Delhi.
Take the kitchen. Gas burners and certain cooking methods—like stir- and deep-frying—generate significant levels of volatile organic compounds (VOCs) and other emissions. Over the long term, this can impact health, especially if your kitchen is not well ventilated.
The other common activity that can lead to higher particle and toxin levels is cleaning—even more so during the pandemic, which has led to greater use of disinfectants and cleaning agents. Without proper ventilation, these too can expose you to the VOCs “off-gassed” or emitted by them.
“Any chemicals that release fumes or gases definitely add to the pollution. There’s no doubt about it,” says Dr Suri.
According to the US Environmental Protection Agency, VOCs could have both short- and long-term health effects, ranging from eye, nose and throat irritation to damage to the central nervous system. In fact, concentrations of many VOCs are consistently higher indoors (up to 10 times more) than outdoors.
So apart from letting in fresh air when the ambient AQI improves to satisfactory levels, what all can you do?
A good air purifier, paired with a monitor to track air quality, can prove handy. Ensure the air purifier comes with a HEPA, or high-efficiency particulate air, filter that is capable of straining out microscopic particles. Most of the latest air purifiers do have these filters. A pre-filter that catches the bigger particles first would be a bonus.
Air quality monitors like the Laser Egg+ Chemical from Kaiterra measure VOCs, apart from the more usual PM 2.5 and PM 10. You even get portable, hand-held monitors. The multi-functional Temtop M2000C, for instance, can measure everything from PM 2.5 and PM 10 to CO2 (carbon dioxide), temperature and humidity levels.
Air purifiers “will improve the air quality indoors,” says Dr Suri. And in the case of elderly people who spend most of their time indoors, he adds, “there is data to show that it might improve their condition in general”.