Centimeters lost to smoke: Household air pollution and stunting in Indian children
with Souvik Datta (Glasgow University)
About half of the world’s population still uses solid fuel, such as wood, coal, dung and crop residue, for cooking (Legros et al., 2009; Rehfuess et al., 2006; Smith et al., 2004). This reliance on solid fuels, not just for cooking but also heating, in developing countries has exacerbated health problems among their populations (Fullerton et al., 2008). The combustion of solid fuels releases fine particulate matter, carbon monoxide, benzene, formaldehyde, and other substances into the surrounding air (Smith, 2000) that are damaging to the health of individuals exposed. The problems often get compounded by the lack of adequate ventilation in indoor areas.
Epidemiological studies show that exposure to household air pollution (HAP) can cause, among others, acute respiratory infections, including lung cancer, tuberculosis, asthma, blindness, and potentially heart diseases and low birth weight and stillbirth (Branca and Ferrari, 2002; Dewey and Begum, 2011; Hoddinott et al., 2013).
In this paper, we focus on a particular health impact of HAP, namely its link with child stunting
and wasting. A child is regarded as stunted if their height-for-age is below certain thresholds set as per the WHO (World Health Organization) Child Growth Standards. Similarly, a child is considered to be wasted if their weightfor-age is below a certain threshold set by the WHO.
About a third of Indian children under the age of five have chronic growth deficiencies. We use data from the newly-released 2015-2016 National Family Health Survey in India to establish a link between exposure to household air pollution from burning solid fuels and child stunting and wasting. We use accessibility to clean fuel as an instrumental variable to identify a causal effect of cooking with solid fuel on child stunting and wasting.
We find strong evidence that exposure to solid fuel smoke negatively affects height- and weight-for-age measures for children, increasing the probability of being stunted and wasted at both moderate and severe levels. The instrumental variable approach estimates that, on average, about 32% of the differences in both height and weight of children can be attributed to exposure to solid fuel smoke. The impact is twice the estimates obtained using ordinary least squares and highlights the importance of taking urgent action. Our results offer strong quantitative evidence that can be used to simultaneously engage in child health care and environment initiatives.