The AQI is an index for reporting daily air quality

0-50 201-300 51-100 301-400 research scholar at CRRI.

Experts said that while any form of combustion could push up levels of finer particulate matter, the concentration of VOCS shoot up because of use of room fresheners, deodorants, paints, polishing and cleaning agents.

“The concentration of VOCS was particularly found to be nearly two times higher than the safe limits inside corporate offices and hospitals. It was also very high in the indoor air inside multiplexes. In residences, the level of PM2.5 was found to be 137μg/ m3, which is over two times the safe limit,” said Radhan Goyal, deputy director of IPCA.

“Indoor air pollution is particularly higher because of improper ventilation. In air-conditioned buildings, it is the stale indoor air which is circulated 101-200 401-500

Prominent pollutant PM10, PM2.5

instead of allowing fresh outside air to come in, as it requires consumption of more energy. Pollution tends to be higher at the corners of the room,” said Mukesh Khare, a professor of environmental engineering at Iit-delhi

Experts said that these studies are in tune with several other studies carried out across the world and also by the Central Pollution Control Board. “VOCS, many of which are carcinogenic, tend to move towards cooler temperatures. The wind inside a room is also stagnant compared to outdoor,” said T K Joshi, environmental health advisor to the union environment and forest ministry. He said a previous study done by CPCB a few years ago had also found that indoor pollution in flats (residences) was higher than outdoor pollution.