With winters setting in and the stubble-burning season picking up in the northern region, the pollution levels in the national capital are set to rise in the coming days. The Delhi government has already implemented its Winter Action Plan. Delhi is bracing to battle the hazy winters with anti-smog guns (ASGs).
What does Winter Action Plan entail?
Anti-smog guns have been made mandatory at all construction and demolition sites larger than 5,000 square metres. Earlier, construction and demolition sites that were larger than 20,000 square metres were needed to install anti-smog guns to control dust pollution. There will be four categories of level of pollution instead of five in the new Plan: Poor (AQI 201-300), Very Poor (AQI 301-400), Severe (401-450), Severe Plus (AQI 450+).
Now, Graded Response Action Plan (GRAP) measures will be implemented three days in advance based on forecasts before the air quality worsens.
Delhi Chief Minister Arvind Kejriwal has announced the 15-point winter action plan for curbing pollution and said 611 teams have been formed to check garbage burning in open besides running anti-dust campaign. The action plan is focused on issues like stubble burning, dust pollution, smog towers, and vehicle emissions among other aspects.
What are anti-smog guns?
Anti-smog guns were first tested back in 2017. Since then, many have been installed at key locations. It's a device that sprinkles fine nebulized water droplets into the air to help in absorbing the smallest dust and polluted particles. The gun which is mounted on a vehicle is connected to a water tank that helps in converting the water into a fine spray with droplets size of 50-100 microns by passing it through high-pressure propellers.
Anti-smog guns, also known as spray gun, mist gun, or water cannon, is said to control air pollution by binding dust and other particulate matter (PM2.5 and PM10) and bringing them down to the ground level along with water.
It works through a canopy effect just like rain to bring down the suspended particles wafting in the atmosphere. The water spray can be taken to a height of 150 feet to spray water 30-100 litres per minute.
Apart from controlling air pollution in cities, the gun is also used in controlling industrial dust in mining, grinding, coal, and stone crushing. In fact, the devices were also used in the recent demolition of the Noida twin towers.
Such a gun comes with different nozzle and propeller configurations. Coarser nozzles are typically used at mining and construction sites and can be customized as well for urban areas.
The Central Pollution Control Board guidelines water throw distance ranges from 30 metres to 100 metres depending on the device which can also be rotated. Treated waste water is not to be used in the anti-smog gun. The guns that are “customised for urban areas” use 40 to 250 litre of water per minute depending on the device, as per the guidelines.
Does ASG help in curbing pollution levels?
These devices are believed to have only a limited impact. There is no thorough scientific analysis as of now to determine the efficacy of the device in controlling pollution, but there could be some brief effect at best, believe environment experts. Dipankar Saha, former head of the CPCB’s air laboratory told the Indian Express that ASG is not a permanent solution. “If the anti-smog gun is used along the roadside, the particulate matter may settle. It may reduce particulate pollution, but it is not a permanent solution,” Saha told the publication. He added that ASGs are used in emergency situations such as a fire or for construction and demolition dust in order to control the situation from aggravating in nearby areas.
“This system can’t be applied in an area like Delhi. It can only work in a confined area like a stadium and not in open areas,” Saha had said who observed the trial run of ASG at Anand Vihar on December 20, 2017, according to the news agency IANS report.