How India’s Air Pollution Crisis Impacts The Poor The Most
While India is home to 22 of the 30 most polluted cities in the world, a new paper published in the journal Nature Sustainability delves into how low-income populations in the country are disproportionately shouldering the public health impacts of air pollution. The study found that high-income, urban Indian households are responsible for the majority of outdoor air pollution, all thanks to their indirect fine particulate matter (PM)2.5 emissions through transport and manufacturing process of the goods they consume.
PM2.5 is a form of air pollution that refers to tiny particles and droplets in the air that are two and one half microns or less in width. All thanks to their minute size, they can travel deeply into the respiratory tract and swiftly reach the lungs. While the short term health impacts of PM2.5 are irritations in the eyes, nose, shortness of breath, and coughing, in the long term, it can affect lung function and even result in heart disease, lung cancer, and asthma.
Every year, breathing air with high levels of PM2.5 causes around 4 million deaths globally. According to the study’s researchers — Fabian Wagner from the International Institute for Applied Systems Analysis (IIASA), Narasimha Rao from Yale School of Environment, and colleagues — about 25 percent of these deaths occur in India.
The researchers wrote that the poorest Indian households suffer from the double burden of air pollution. One major source of air pollution is from burning wood, cow dung, and other solid fuels for cooking food in low-income households due to lack of access to clean cookstoves.
Over a decade ago, in 2010, more than 150 million solid fuel burning cook stoves were the most lethal source of PM2.5-related emissions in India. Researchers estimated that they might have caused about 900,000 premature deaths.
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Yet, the contribution of these cookstoves to outdoor air pollution is only 40 percent of that as compared to other PM2.5 sources that are triggered by household consumption in India.
“Low-income households face the brunt of all pollution sources— not only do they suffer indoor air pollution from their own cooking, but they also face a disproportionate share of mortality risks from ambient air pollution (outdoor air pollution), including from electricity generation and other industries to which their consumption contributes relatively little,” the researchers wrote.
This study’s findings further highlight how air pollution is not only among the leading causes of premature mortality worldwide, but could also be a marker of the unequal environmental impacts of economic development.
These findings are consistent with previous researchfindings that have shown lower socioeconomic regions of countries, particularly in North America, United Kingdom, Asia and Africa, have higher concentrations of PM2.5.
Another study that was conducted in India found that mortality is inversely correlated with income and assets.
Recent studies that examined the relative contribution of different sources of air pollution in India and the impact of clean cookstoves on air quality show that the residential sector contributes 20–50% of ambient PM2.5 concentrations from direct fuel use.
In fact, eliminating household use of kerosene and solid fuel such as wood or dung cakes would enable many parts of India to meet the National Ambient Air Quality Standards and also have substantial climate co-benefits. At present, the majority of premature deaths from PM2.5 and ozone pollution are in rural regions of India. The reason? Biomass-burning cookstoves used in lower-income rural households.
However, what remained unclear was how the contribution of Indian households to ambient air pollution compares to the mortality risks that they face from PM2.5 concentrations.
In this study, the researchers found that higher-income, predominantly urban households contribute to ambient air pollution indirectly from vehicles, electricity use and the manufacturing of the products that they consume.
“Our study found that transport and indirect emissions associated with household consumption contributed almost twice as much to ambient PM2.5 concentrations as direct emissions from biomass cook stoves,” the researchers wrote.
“Furthermore, the mortality risk from these indirect sources falls disproportionately on lower-income households, exacerbating the mortality risks that they already face from using biomass-burning cook stoves,” they added in the paper.
The researchers combined data from different sources and used an input–output model to calculate consumption-based PM2.5 contributions by income decile groups (from the poorer 10% to the richest 10%). That also included the mortality burden within the same groups.
Their modelling revealed that the main contributors to polluting emissions are higher-income households through transport and the manufacture of goods they consume.
Despite that, dying prematurely due to prolonged exposure to air pollution from fine particulate matter in the lowest-income households is nine times higher than in the highest-income households.
“Indirect contributions from more-essential commodities such as food and clothing are distributed relatively evenly across deciles, whereas those from electricity, transportation and waste are highly correlated with income,” the researchers observed.
The study further found that food production and preparation, plus waste, together comprise 70 percent or more of Indian households’ total PM2.5 contributions across socioeconomic groups. The higher a household’s income, the more waste they dispose off. On the other hand, their cooking-related air pollution contributions decreased with rising income.
But the most surprising finding was that despite the public image of Indian cities teeming with traffic congestion, the share of transport to air pollution is only 6 percent on average, and 11 percent for the richest 10 percent of Indian households.
Whereas rural food particulate matter footprints are higher than urban ones due to the higher share of grains in their diet, which tend to have a higher fertilizer use, the researchers wrote. However, the contribution of emissions from waste is much higher for urban households.
The authors highlighted the importance of addressing indoor air pollution sources such as using clean fuels for cooking while also focusing on industry-wide pollution controls for reducing PM2.5 pollution inequity in India.