Mercury, microplastics in Capital’s atmosphere raise health alarm: IITM study

New Delhi: A fresh scientific investigation has added a worrying layer to Delhi’s already grim air quality story, dangerous levels of mercury have been detected in the city’s atmosphere. The study, carried out by the Indian Institute of Tropical Meteorology (IITM), Pune, has for the first time provided a long-term assessment of mercury in Delhi’s air, analysing data from 2018 to 2024.

On average, the capital’s air contained 6.9 nanograms of mercury per cubic metre, far above the global average for both hemispheres. In comparison, the Northern Hemisphere records around 1.7 nanograms per cubic metre, while the Southern Hemisphere averages 1.3. Mercury, a toxic heavy metal identified by the World Health Organization (WHO) as one of the top 10 chemicals posing serious risks to human health, is known to damage the nervous, digestive, and immune systems when exposure is prolonged.

The findings, published in the journal Air Quality, Atmosphere and Health by Springer, revealed that human activity accounted for the bulk of emissions. Fossil fuel burning, industrial processes, and vehicular exhaust were responsible for 72–92 per cent of mercury levels in Delhi’s air. The rest was attributed to natural processes such as soil re-emissions and sunlight-driven chemical reactions. Researchers observed a slight decline in mercury levels over 2018–2024, but concentrations remain high, while a separate study detected microplastics in PM10, PM2.5, and PM1 fractions. Adults inhale nearly twice as many particles in summer, raising risks of bronchitis, pneumonia, lung inflammation, and cancer. Both studies highlight urgent need for integrated pollution control strategies.