Air Quality in India Got Worse Since the Installation of Outdoor Air Purifiers: Here’s Why


With the onset of winter, air pollution in India is soon going to reach the crisis level once again. On an individual level, we can wear masks and use air purifiers in our homes, but more broadly, cities and municipalities have also been installing outdoor air purifiers for many years – but do they really work? Have smog towers and outdoor air purifiers affected the air quality in India? Despite outdoor air purifiers and smog towers, the concentration of PM2.5 in India’s air is currently 5.2 times higher than the WHO’s annual air quality guideline. The air quality in India is not getting better even after all the money and efforts to curb the problem of air pollution in the country. We talked to several experts and tried to understand why this is so, and whether any better solutions are possible.

In an effort to reduce the air pollution problem in India, cities such as Mumbai have been deploying Wind Augmentation Purifying Units (WAYU) since 2015. Major Indian cities such as Delhi and Bengaluru have also resorted to installing outdoor purifiers and smog towers along city streets in an effort to curb pollution problems. Delhi got a new smog tower at Connaught Place in August this year.

So far, India stands Third in the list of top ten countries with the worst air quality in 2020, comes only after Bangladesh and Pakistan. According to Research By the Council for Energy, Environment and Water (CEEW) – a Delhi-based policy research institute – Delhi’s air quality in winter in 2020 was worse than in winter 2019 despite the lockdown. The study also found that residents of Delhi were exposed to air that did not meet national ambient air quality standards (60 µg/m3) for more than half of 2020, despite this for nearly eight months (March to November). ) because of the low level of economic activity. For the pandemic-induced lockdown.

According to Tanushree Ganguly, air quality researcher at CEEW, the air pollution India is facing is the problem of urban infrastructure. “If there is any unpaved road, there is bound to be more dust in it,” Ganguly said. “Vehicle pollution also causes air pollution. In winter, a significant amount of pollution also comes from biomass that people burn for their heating needs.”

Are outdoor air purifiers the solution to the problem of air pollution?

The WAYU instruments have been jointly developed by the National Environmental Engineering Research Institute (NEERI), Council of Scientific and Industrial Research (CSIR), and the Indian Institute of Technology-Bombay (IIT-B). WAYU units were established in 2018 at some prominent locations in Delhi.

Dr. Prashant Gargava, Member Secretary, Central Pollution Control Board, said at the time of inception, “Its makers claim that it can reduce pollution by 40-60 per cent at busy traffic junctions.”

“The level of air pollution varies depending on the time of measurement,” Ganguly said. “So when it was measured, in which area the air quality is being improved – whether it is within ten meters of the air purifier or within 500 meters of the air purifier – all these factors need to be considered to show that that it’s actually making any impact. I can’t find any publicly available research or databases that explicitly say that WAYU instruments actually affected air quality within a 500-meter radius.”

“There is a constant dynamic in the system and you are not trying to address the sources of pollution that exist at this time; You’re also trying to address sources that are out of town. I think the idea is to have credible evidence about their impact before they go ahead and across the city.”

In addition to installation costs, outdoor air purifiers come with several additional costs, said Vivel Chattopadhyay, senior program manager for the clean air program at the Center for Science and Environment (CSE), a Delhi-based research and advocacy organization.

This includes cost of maintenance, cost of filters which will have to be replaced from time to time, components like sensors which require periodic calibration, operating cost, manpower, cost of land which is being occupied by air pollutants and much more. These problems are not easy to solve, but companies that make these solutions are also aware of them and are working on solutions.

“Our outdoor air purifiers have nano-filters that can be reused up to four times, thus significantly saving on maintenance costs,” said Rajiv Krishna, founder, Bengaluru-based product development company Atektron. Atektron has installed its outdoor air purifiers at locations including Marathahalli Junction, Whitefield and PR Nagar in Bengaluru.

How exactly can we solve the problem of air pollution?

CEEW in its research suggested that Delhi needs a dedicated Air Quality Forecasting Cell to facilitate the rollout of preventive measures. “If we have a forecast for the next 72 hours, we can clearly see the contribution ratio to pollution – for example, urban dust is highest at night,” Ganguly said. “Probably, it is because of the trucks at night. Governments can take measures to cut back on the activities they can actually do through forecasting – these activities are very difficult to execute because of the significant economic repercussions.”

Chattopadhyay said, “Wherever there is a massive reduction in pollution in the world, the solution is working to control pollution from clean fuels and sources, where pollution is coming from is better assessed and studied. “

Chattopadhyay said that the amount of money being spent on outdoor air purifiers can be used to reduce emissions from the sources. “Such amount can be spent to buy electric buses, you can have garbage collection and segregation centres. This will eliminate the root cause of the problems. This will give us better long term gains. Outdoor air purifiers are really futile endeavors. The government is allowing pollution to be free from the source. Emissions are coming from industry, vehicles and many sources. Deduction from source will also have cascading implications in terms of risk,” Chattopadhyay said.

Ganguly also suggested that there is a need to improve transit infrastructure including waste collection, waste transport and waste management infrastructure. “In winter, a significant amount of pollution also comes from biomass that people burn for their heating needs,” she said. “Delhi shelters might not be able to cater to all the homeless people in Delhi. So I think it is also important how the government plans to upgrade these existing shelters, so that at least their use is better. At night, if these shelter homes can accommodate the homeless population, their reliance on waste or dry leaves for their heating needs may be reduced.

Chattopadhyay also said that stricter emission control norms should be in place. “Strict emission control norms for power plants will reduce (air pollution). The government has to channel the money into the right sources – cutting emissions from sources and maintaining regulations. Smog towers are not the right policy decision. Such methods signal to the polluters that it is okay to pollute,” he said.

one strip solution

Atektron’s Krishna disagreed with the researchers’ suggestions that forecasting and air quality monitoring is a better solution. He suggested that strategically installing outdoor air purifiers within two-three kilometers of each other throughout the city would definitely reduce air pollution.

Angad Daryani, founder of Prana, a deep tech startup that makes outdoor air purifiers, also said that what the NCR government is doing with smog-free towers is unscientific. When asked whether outdoor air purifiers can really contribute in solving the problem of pollution in India, he said that outdoor air purifiers from Prana work as a bandage solution to the problem of pollution, whereas we transition to clean energy.

I asked Ganguly if it was so, but she did not agree. “Let’s not call it a solution before we make sure it is one,” she said. “Once all the measures have been taken and if we still don’t see any significant impact, maybe this can be looked at as a solution. But it cannot precede all other solutions. As a researcher, that’s the problem I have.”


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