NEW DELHI: A study has demonstrated a clear association between components of PM2.5 pollutants with low birth weight, anaemia and acute respiratory infection among children under the age of five years in India. For every 10 micrograms per cubic metre increase in PM2.5 exposure, anaemia, acute respiratory infection and low birth weight prevalence increase, respectively, by 10%, 11%, and 5% in the children, the study said.
The study published in journal Nature Communications on Wednesday says that the major health risks of PM2.5 were posed by exposure to NO3 (nitrate), NH4 (ammonium), EC (elemental carbon) and OC (atmospheric organic carbon).
According to the study titled ‘Cumulative effect of PM2.5 components is larger than the effect of PM2.5 mass on child health in India’, N03, EC and NH4 were more associated with these three health outcomes than other PM2.5 components. It states that total PM2.5 mass as a marker for air pollution exposure could be underestimating the true impact of the different components of PM2.5.
“PM2.5 is composed of different components, including sulphates, nitrates, ammonium, elemental carbon, organic carbon and metals. PM2.5 mass concentration depends on different sources and geographical areas. However, some PM2.5 species are more toxic than the others,” said Sagnik Dey, Institute Chair Professor, Centre for Atmospheric Sciences, Indian Institute of Technology, Delhi, and an author of the study. “The composite effect of exposure to various PM2.5 species on child health is more than the effect estimated using only PM2.5 mass concentration.”
Dey added, “The study is a good start to help policymakers identify pollution sectors that are more harmful than others. The authorities can take mitigation steps on a priority basis in high-impact sectors.”
The other major authors of the study are Ekta Chaudhary of IIT-D’s Centre for Atmospheric Science, Franciosalgeo George from the division of epidemiology, biostatistics and population health at St John’s Research Institute, Bengaluru, and Santu Ghosh of the department of biostatistics, St John’s Medical College, Bengaluru.
The study says, “We demonstrated a significant association between components and sectors contributing to PM2.5 with low birth weight, anaemia, and acute respiratory infection among the children under the age of five years in India. Our study further showed that children born with low birth weight are more highly impacted due to PM2.5 component exposure than children born with normal birth weight.”
It added that meeting the national ambient air quality standards (NAAQS) would take the anaemia burden closer to the ‘anaemia-free India’ mission target (reducing the prevalence to 40%) of the central government.
For the study, the researchers estimated the association of ambient PM2.5 and its components and emitting sectors on three health outcomes by combining anthropometric measurements, blood biomarkers and socioeconomic information from the fourth round of the national family health survey (NFHS-4).