Around 25 research studies and papers published between 2018 and October 2023 seen by DTE, show that poor air causes low birthweight, stunting and death
As Delhi chokes due to the impact of smog, an analysis by Down to Earth (DTE) of 25 research studies and papers published between 2018 and October 2023, shows the impact of air pollution on India’s children is not restricted to Delhi or North India.
Air pollution impacts a child’s health starting in the foetus. Low birthweight (LBW), preterm delivery, and stillbirth have all been linked to pregnant women who have been exposed to poor air quality, according to the research studies and reports viewed by DTE.
Poor quality of air also results in developmental delay, growth failure, poor respiratory and cardiovascular health, and risk of anaemia.
The link between air pollution and birthweight was highlighted by a 2018 study conducted in Tamil Nadu. A 10-μg/m3 (microgram per cubic metre) increase in particulate matter (PM2.5) exposures during pregnancy was linked to a 4 gram drop in birthweight and a 2 per cent rise in the prevalence of LBW.
A pan-India study in 2021 too provided a strong evidence of the association between intra-uterine exposure to ambient PM2.5 and LBW in India.
Policies to enhance air quality may be required to meet the World Health Assembly’s goal of a 30 per cent decrease in LBW by 2025, according to the study led by experts from Delft University of Technology and Harvard University. It involved more than 149,416 children nationwide.
Air pollution has a negative impact on children’s development and is linked to stunting, researchers from Germany’s Heidelberg University and France’s University of Rennes showed in their study published in the Journal of Environmental Economics and Management.
The percentages of stunted and severely stunted children in India would drop by 10.4 and 5.17 percentage points, respectively, if average pollution levels were reduced to World Health Organization-recommended levels, according to research published in May 2022.
Ambient PM2.5 exposure causes anaemia in children with under five years of age in India, a district-level study in 2021 found. It revealed that the average prevalence of anaemia rose by 1.90 per cent for every 10 μg/m3 increase in ambient PM2.5 exposure.
Although research has been done on the effects of ambient fine PM2.5 on children’s health, a very recent, first-of-its-kind study found a significant correlation between the chemical components of PM2.5 and LBW, anaemia, and acute respiratory infections in children under the age of five in India.
The study, published recently in the journal Nature on October 31, 2023, showed that for every 10 μg/m3 increase in PM2.5 exposure, anaemia, acute respiratory infection, and LBW prevalence increase by 10 per cent, 11 per cent and 5 per cent respectively, among children under five in India.
PM2.5 is a mixture of various components with different sources and toxicities. Each source may produce different PM2.5 components. The study showed the cumulative effect of PM2.5 components — NO3–, NH4+, EC, and OC — to be larger than the effect of PM2.5 mass on child health in India.
The study provides indigenous evidence to prioritise control strategies for reducing exposure to more toxic components, in order to achieve greater child health benefits in India, according to the authors.
The DTE analysis of the studies also showed that air pollution has increased the number of hospital admissions for respiratory diseases.
For instance, in Ahmedabad, an increase in the concentration of PM2.5 was found to be associated with an increase in the percentage of respiratory admissions according to a study published in June 2022.
Ambient air pollution increases the risk of hospital admissions for asthma and wheeze among children and adolescents according to a July 2023 Mysuru-based study.
In Mysuru, an increase in NO2 concentration was associated with an increase in asthma-related hospital admissions. A 10 µgm3 (or 10 per cent) increase in NO2 increased admissions by over two-fold in the city, the study led by researchers from La Trobe University, Australia and Department of Respiratory Medicine, JSS Medical College, Mysuru, found.
Every third child in Delhi is asthmatic and suffers from airflow obstruction.
Dying young
A Delhi-based study, published in April 2022, was the first evidence of association between acute exposure to PM2.5 chemical species and mortality, its authors claimed. They specifically cautioned about the mortality risk from PM2.5 components during winters.
Another pan-India study, released in April 2022, found a strong correlation between infant death and exposure to dangerous PM2.5 levels during the third trimester.
According to the State of Global Air 2020, a global study, air pollution killed over 116,000 newborns in India in that same year within 27 days of their birth. This indicates that a newborn dies in the country from health concerns associated with air pollution once every five minutes.
Particulate pollution is the biggest risk to the health of an Indian child born today in terms of life expectancy.
Globally, on average, a baby born today can expect to have its life shortened by one year and eight months. In India, the lifespan of a child born today is likely to reduce by 5.3 years due to PM2.5 according to research from the Energy Policy Institute at the University of Chicago.
State of Global Air 2020 showed that 539 children died due to air pollution a day in India. Twenty-two children died every hour.
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