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Tuesday, Dec 10, 2019

How bad is indoor air? IIT Delhi to study 10 public spaces

People spend at least 60% of their time indoors, increasing exposure to particles and risk of respiratory illness.

education Updated: Nov 10, 2019 13:31 IST
Vatsala Shrangi
Vatsala Shrangi
Hindustan Times, New Delhi
Potential threat of high indoor pollution levels is mainly owing to poor ventilation and lighting, high ambient air pollution, among others. (Representational image)
Potential threat of high indoor pollution levels is mainly owing to poor ventilation and lighting, high ambient air pollution, among others. (Representational image)(Unsplash)

Soon, the national capital will have an estimate of pollution levels in indoor public places with a high concentration of people such as schools, colleges, residential colonies, hospitals, Metro stations, malls, markets and multiplexes, among others.

The Indian Institute of Technology (IIT)-Delhi’s Centre of Excellence for Research on Clean Air (CERCA) has started a pilot study of 10 such micro-environments across the city to measure real-time concentration of particulate matter (PM)2.5 – the most harmful pollutant — prolonged exposure to which could lead to respiratory illnesses.

“We have identified six sites under each micro-environment, which means levels of different pollutants will be measured across 60 different locations across the city. We will examine outdoor/indoor ratio of pollution levels in these micro environments, so that based on the outdoor pollution level, we can predict the indoor concentration. The sites have been chosen keeping in mind their high footfall, and are mostly in low and middle-income group areas. There will be a mix of government and private institutions,” Sagnik Dey, associate professor, Centre for Atmospheric Sciences, and coordinator, CERCA, said.

The other parameters that will be studied include PM10, carbon dioxide and volatile organic compounds (VOCs). Pollutants like CO2 and VOCs are mostly higher indoors, he said.

Until now, no such assessment has been done in places where people spend at least 60%-70% of their time and, therefore, have heightened exposure. The study has already started at two sites.

“In the first phase, we will just study the PM levels through calibrated potable remote sensors to get a snapshot on how these places fare in terms of PM concentrations. In the second, we will probe deeper into the reasons behind these concentrations and make suggestions on what could be done,” Dey said.

The potential threat of high indoor pollution levels is mainly owing to poor ventilation and lighting, high footfall, high ambient air pollution, use of carpets, cleaning agents and lack of good sanitation practices, experts said.

The project proposes to collect data from each of the 60 sites by monitoring air quality during two peak pollution windows in the capital — from mid-October to mid-November, and mid-December to mid-January.

A model will be developed to estimate indoor pollution. This estimate could be used to advise people to vacate such places, if needed, for a particular duration.

“Based on the analysis, we will present our suggestions to the government as well as the CPCB (Central Pollution Control Board),” Dey said. The study is being taken up in collaboration with Society for Indoor Environment and is part of the overall projects being taken up by IIT-D for devising effective solutions to air pollution.

D Saha, former head of CPCB air laboratory, said, “Indoor air quality is much more important in comparison to outdoors, as the level of concentration, in particular of VOCs, is higher, as there is no exchange with the natural air. Outdoors, the air is constantly renewed and the pollutants keep getting dispersed.”