The BBMP has agreed to install 500 air purifiers at busy traffic junctions in order to reduce air pollution in Bengaluru.

To combat Bengalurus air pollution BBMP needs more than just air purifiers Experts
news Pollution Monday, August 26, 2019 - 18:40

The Bruhat Bengaluru Mahanagara Palike (BBMP) is looking to tackle air pollution in Bengaluru by installing 500 air purifiers at busy traffic junctions. This comes after the first air purifier was installed in Hudson Circle as a pilot test in February.

The civic body has entered into an agreement with ATechTron, a software firm and a manufacturer of air purifying devices which filters PM 10 and PM 2.5 particulate matter including dust, smog and petroleum fumes. According to the manufacturers, the device can cover a radius of 70 to 90 feet.  

‘Results alarming’

Preliminary findings from the pilot run at Hudson Circle showed alarming results. According to the National Ambient Air Quality Standards, PM2.5 concentrations should not be above 60 µg/m3 and PM 10 concentrations should not be above 100 µg/m3 over a period of 24 hours. The measured concentration of PM 10 and PM 2.5 levels during the pilot at Hudson Circle were found to be 89.51 µg/m3and 47.6 µg/m3 respectively during 8 hours of peak traffic alone. The data showed that particulate matter was at least 2.5 times more than the limit in the city.

The makers of the air purifier device believe that this offers a technological solution to the problem of filtering fine dust particles from the city's air. 

"The results from the dust collected in the pilot run in Hudson Circle showed that the dust contained particles such as PM 10 and PM 2.5 and heavy metals such as Cadmium, Chromium, Lead, Zinc, Copper, Iron, Manganese, Barium and other harmful pollutants. On an average, 20-25 grams of fine dust particles were collected every day," stated Rajeev Krishna, founder of ATechTron. 

In a month, over 650 grams of fine dust particles were collected by the device. ATechTron now plans to install 500 such devices in the next year, including multiple devices in busy traffic junctions like Silk Board, Marathahalli and South End Circle. 

Installing air purifiers on a large scale has not been attempted elsewhere in the country, including in New Delhi where other attempts like spraying atomised water from water cannons were tried. In the Chinese city of Xi'an, an air-purifying tower was built while in London, N-OX eating paint was promoted as a solution. 

Why experts are sceptical

But experts are still sceptical of attempts to clean outdoor air using filtering devices. "As a matter of principle, it is difficult to 'clean' air like this because the volume of air in the atmosphere is large. Experiments on this are yet to give significant results. In a 1 km square area, there is a huge volume of air and the purifier will be working on a minuscule part of it," explains SN Tripathi, a professor at Indian Institute of Technology, Kanpur (IIT-K) who specialises in atmospheric science. 

Activists have long campaigned for curbs on registration of vehicles in the city and planting more trees as measures to tackle air pollution. There are more than 80 lakh vehicles on the city's roads with as many as 1,752 vehicles being added every day, according to figures compiled by the Transport Department. "All indications seem to be that installing air purifiers is a drop in the ocean and will not be a solution to the problem of air pollution," says Srinivas Alavilli, a Bengaluru-based activist and member of the group Citizens for Bengaluru (CfB). 

However, the manufacturers of the air purifiers say they are concentrating on a particular portion of the air between 4 and 7 feet from the ground to improve the air quality at the breathable height.  "This will help pedestrians walking on foot, riders travelling on a two-wheeler and people like traffic police officials who suffer due to prolonged exposure to air pollution in busy junctions," adds Rajeev. 

The cost of maintaining an air purifier and the electricity required to run it has also been questioned. The filters need to be replaced every month and each air purifier uses around 500 watts of energy. The makers say that this is a third of the energy used by an air-conditioner but experts say that it will add to the carbon footprint of the city unless it is fully propelled by solar energy. 

"We want to implement this using solar and wind energy but it requires a big space in a junction since we have to install a solar panel. We are still working on making this happen," says Rajeev. The fine dust particles, which include heavy metals, also need to be stored away somewhere since they will get mixed with the soil if it is dumped into landfills.

Studies show rise in heart problems

Earlier studies corroborate the findings during the analysis of the dust collected by the air purifier at Hudson Circle – that there are hazardous levels of particulate matter in the air in Bengaluru during peak traffic hours. A study by Aishwarya Sudhir published by Climate Trends and Co Media Lab, a city-based organisation, found that vehicular pollution contributed to as much as 60-70% of the air pollution in the city.

Studies also show that the rise in air pollution increases the risks of heart diseases since the PM 2.5 materials cross the air alveolar membrane, which usually acts as a filter of the lung, and get deposited in the blood vessels of the heart and causing clot deposition. Statistics compiled by Jayadeva Hospital in Bengaluru showed a marked rise in heart attack cases in the under 40 age group, particularly among people exposed to the outdoor air for long hours like drivers of public transport vehicles.

The BBMP set aside Rs 5 crore for the installation of air purifiers in the city in the 2018-19 budget but after companies showed interest, the devices will now be set up at zero cost for the civic body. ATechTron will be installing the devices at a cost of Rs 3 lakhs each using Corporate Social Responsibility (CSR) funds for the next ten years but it remains to be seen if these devices will help tackle the alarming levels of pollution in the city's air. 

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