CHENNAI: A new study has sounded the alarm on what scientists are calling a “new air pollutant” — inhalable microplastics. These are microscopic plastic fragments, less than 10 micrometres wide, small enough to slip deep into human lungs. While attention has long focused on fine dust such as PM2.5, researchers say its plastic equivalent — polymer dust — is now floating freely in the air we breathe.

Published in Environment International, the study is the first systematic investigation of airborne microplastics (iMPs) across Indian cities. It was conducted by researchers from the Indian Institute of Science Education and Research (IISER) Kolkata, AIIMS Kalyani, and the Institute of Mathematical Sciences (IMSc), Chennai.

Air samples were collected from bustling marketplaces in Kolkata, Delhi, Mumbai, and Chennai. In Chennai, the team sampled five high-footfall locations — T Nagar, Ritchie Street, Phoenix Marketcity, Parry’s Corner, and Zam Bazaar Market — to capture real-world exposure levels.

Using advanced pyrolysis–gas chromatography–mass spectrometry (Py-GC-MS), the scientists detected an average of 8.8 micrograms of plastic per cubic metre of air across all cities. In Chennai, the concentration was about 4 µg/m³, lower than Kolkata (14 µg/m³) and Delhi (13 µg/m³) but still significant. Researchers say the city’s coastal winds help disperse pollutants faster than in landlocked regions, but that does not make the air safe.

“Although coastal ventilation helps, the presence of synthetic fibres from clothes, plastic dust from waste sorting, and debris from packaging means the exposure is continuous,” the study notes.