February 20, 2021 1:31:41 am
A survey of indoor air quality in 37 buildings of the city, conducted by Indian Institute of Technology (IIT) Delhi, has revealed that schools and colleges have the highest concentration of PM 2.5 and PM 10 compared to other buildings such as offices, restaurants and malls.
Overall, concentration of both PM 10 and PM 2.5 was two-and-half times higher than the permissible limit set by Central Pollution Control Board (CPCB) for ambient air quality. The survey also revealed that schools have the worst I/O (indoor/outdoor) ratio of all surveyed buildings, meaning it had more indoor sources of pollution as compared to outdoors. A total of six schools and six colleges were surveyed.
It was undertaken by the Centre of Excellence for Research on Clean Air (CERCA), IIT-Delhi; Society for Indoor Environment (SIE); and Kaiterra, an air quality instrument company.
Researchers noted that use of chalk could be a major factor. “Use of chalkboards are the primary sources for consistent high concentration of PM 10 and PM 2.5. There is re-suspension of chalk dust with the change in furniture patterns and regular writing/dusting,” Professor Arun Sharma, Director SIE, said during an online event Friday.
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The study also noted that in all buildings, pollutant concentration rose at night. They attributed this to poor ventilation after closing of doors and windows.
Project MAQUID (Monitoring of Air Quality in Urban Indoors in Delhi) was conducted in schools, colleges, hospitals, shopping malls, restaurants, offices and one cinema hall during the peak pollution period from October 15, 2019, to January 30, 2020. Except in the cinema where permission was not granted for monitoring more than four hours, 24-hour monitoring was conducted in most buildings.
“The indoor air pollutants studied include PM 10, PM 2.5, TVOC (total volatile organic compounds) along with comfort parameters (temperature, relative humidity and CO2 concentrations)…,” IIT said in a statement. The researchers said “the concentration of particulate matter (both PM 10 and PM2.5) are recorded 2-5 times higher than permissible limits” and “10-15 times higher than the WHO 24-hour average limits”.
“Educational institutes (schools and colleges) top the list for high PM concentration… TVOC levels are also recorded high, with highest in hospitals and restaurants due to rampant use of chemical cleaning agents, floor cleaners and cooking oils,” Professor Sharma said.
“CO2 levels are also recorded high in hospitals, colleges, offices as well as in restaurants due to higher occupancy and inadequate ventilation,” he said.
Professor Sagnik Dey from CERCA said there was “a pressing need to develop Indoor Air Quality standards in India”. Among the recommendations was that in closed public spaces, it should be mandatory to display indoor air quality.
Meanwhile, halfway through the event, held on Zoom, it was disrupted by somebody by the name of ‘Ramone’ who repeatedly tried to draw obscene images on the presentation. The person also spouted abusive words in an automated, robotic voice. The presentation was stopped for a few moments and the person was removed, after which it continued without interruption. The meeting was only open to those with the meeting code and password.
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