International study led by IIT-M finds reasons for low visibility in north India

A study by researchers on the Indian Institute of Technology-Madras, in collaboration with specialists from Germany, the U.K. and the U.S., has discovered that chloride-rich particles cut back visibility over northern India, together with in New Delhi. The study was revealed in Nature Geoscience.

Several research completed earlier had recognized that particulate matter or aerosol particles with a diameter lower than 2.5 micrometres are a significant pollutant, accountable for haze and fog formation over the Indo-Gangetic Plain.

Since the function of PM2.5 in haze and fog formation over Delhi and its detailed chemistry was not effectively understood, insurance policies couldn’t be developed to enhance air high quality and visibility, although it’s a widespread data that dense fog brings life to a halt, ensuing in extreme monetary losses and endangering human lives.

The study defined that industrial processes and the burning of plastic waste have been accountable for excessive particulate matter. They additionally precipitated advanced chemical reactions involving hydrochloric acid (HC1), which is emitted in the ambiance, ensuing in haze and fog throughout chilly winter nights.

The study was carried out in collaboration with Max Planck Institute for Chemistry, Germany; Harvard University, U.S.; Georgia Institute of Technology, U.S.; and Manchester University, U.K. State-of-the-art devices measured the chemical composition and different vital properties of the particulate matter, apart from the relative humidity and the temperature, in Delhi for a month. The findings stunned the researchers.

Sachin S. Gunthe, affiliate professor in the Department of Civil Engineering on the IIT-Madras, stated, “We realised that despite absolute PM2.5 mass burden over Delhi being much less than the other polluted mega-cities around the world, including Beijing, the pollution and atmospheric chemistry of Delhi is much more complex to understand. This work put forward the importance of measurements and modelling approaches to scientifically conclude that half of the water uptake and visibility reduction by aerosol particles around Delhi is caused by the HC1 emissions, which is locally emitted in Delhi from the burning of plastic waste and other industrial processes.”

The actual problem was to delineate the function of excessive chloride in visibility discount, he stated. “The resolution of the mechanism was derived with the collaborative effort by all the partners with various tools of analysis. This study is a demonstration of a successful large-scale scientific collaborations that are so vital for climate studies,” he stated.

Dr. Gunthe stated, “Scientifically, our job is half-done. The burning of plastic waste can emit highly toxic chemicals called ‘dioxins’, which can accumulate in the food chain, causing severe problems in reproduction and the immune system. We further need to investigate in this direction. Enhancement in the fundamental science of air pollution should be given importance as much as technology development to tackle pollution.”