Kids exposed to indoor pollution from burning of solid biomass fuel have lower IQ: Study

Children who are exposed to indoor air pollution triggered by burning of solid biomass fuel such as cow-dung and wood may be suffering from lower Intelligence Quotient (IQ) levels, a new study has indicated. The study was conducted by a team of medical professors and doctors from the Post Graduate Institute of Medical Education and Research (PGIMER) in Chandigarh. The team analyzed how household air pollution was taking a toll on children’s cognitive function, particularly of those who were exposed to such household air pollution during the first three years of their lives at a stretch.

“The IQ level of children, aged between six and eight years, who were exposed to household air pollution triggered by burning of solid biomass fuel was found to be significantly lower than those children who came from houses where LPG was used as a fuel,” said PVM Lakshmi, professor of epidemiology, department of community medicine and school of public health at PGIMER and the corresponding author of the study. According to the 2011 census, more than 70% of the population in the country resides in rural areas with the widespread use of solid biomass fuel. At least 86% of the rural population use solid biomass fuel, particularly for cooking.

“What adds to the risk is that the infants are almost always carried by their mothers or allowed to play around them when they cook. This practice exposes the child to harmful household air pollution, which can be detrimental to the development of the children,” said Lakshmi.

Data for the study was collected from 108 children, aged between six and eight years, from two village schools at Kheri and Samlehri in Haryana between July 2012 and June 2013. The researches visited their houses in the villages to find out the level of indoor pollution. All the children were tested for their IQ using Malin’s Intelligence Scale for Indian Children (MISIC). The mean IQ was calculated as the average of Verbal and Performance score


“High levels of indoor and household air pollution have their own hazards no doubt. But as this is an epidemiological study, it is not convincing enough to come to a conclusion based on a small sample size. This is, however, an interesting indication,” said TK Joshi, a member of the Central Pollution Control Board-led task force on air pollution.

The researchers said that children from both kind of families - those using solid biomass fuel and families using LPG for cooking purposes – were selected for the study. The samples were taken from similar economic backgrounds and having similar dietary habits.

“We found that at least 55% of the children had borderline or below average IQ levels. The mean IQ of children, who came from houses where LPG was used as fuel, was at least 5.5 points higher than the children who were exposed to indoor pollution triggered by solid biomass fuel,” said Ravindra Khaiwal, additional professor (environment health) at the department of community medicine and school of public health at PGIMER, who led the study. The findings of the study appeared in the March 2020 issue of Science of the Total Environment published by Elsevier.

The union government in 2016 had started the Pradhan Mantri Ujjwala Yojana, popularly known as Ujjwala, to eliminate health hazards poor women face from indoor pollution by increasing their access to clean, smoke-free cooking fuel. The scheme aims to reach 80 million households until March 2020 with free LPG connections.