NEW DELHI: Exposure to ammonium nitrate, a key component of PM2.5 pollution and a product of agricultural emissions, has been found to affect the learning ability and memory in children, according to a new study.
The chemical is formed when ammonia gas -- released from agricultural activities -- reacts with nitric acid produced after burning fossil fuels. PM2.5 is a mixture of dust, soot, organic compounds and metals. In a 2020 study, a team including researchers from the University of Southern California (USC), US, looked at PM2.5 as a whole and found no potential impact on children’s cognition. However, this study, conducted by the same team and published in the journal Environmental Health Perspectives, analysed 15 chemicals constituting PM2.5 and thus, ammonium nitrate emerged as a “prime suspect”.
Based on residential addresses of nearly 8,600 children, aged 9-11 years, from across the country, researchers used spatio-temporal models to analyse yearly levels of exposure to PM2.5 components. “No matter how we examined it, on its own or with other pollutants, the most robust finding was that ammonium nitrate particles were linked to poorer learning and memory. That suggests that overall PM2.5 is one thing, but for cognition, it’s a mixture effect of what you’re exposed to,” study author Megan Herting, a professor of population and public health sciences at USC, said.