May 23, 2024

Wood fires make heavy smog in New Delhi

The Indian capital, New Delhi, has the dirtiest air of any capital in the world. In addition, the extremely dense smog is unique in the world because it seems to defy all laws of chemistry. Fine dust particles form at night, whereas practically everywhere else they only form when sunlight triggers chemical reactions of pollutants. A team led by Sachchida Nand Tripathi of the Indian Institute of Technology in Kanpur and André Prévot of the Paul Scherrer Institute in Switzerland has now explained how particles form when none actually occur. As reported by the group in Nature GeoscienceThe tiny particles produced when wood is burned are behind this phenomenon. It is gaseous and invisible during the day, but when the temperature drops at night, it condenses into visible particles that form a thick smog.