Data from the Air Quality Life Index 2021 shows that failure to meet the World Health Organization (WHO)’s guideline on reducing PM2.5 (particulate matter) pollution to 5 μg/m3 would cut global life expectancy by 2.3 years. AQLI data emphasises that ambient particulate pollution poses the world’s greatest external risk to human health.
South Asia is at the centre of the crisis. According to AQLI data, from 2013 to 2021, particulate pollution in South Asia surged by 9.7%, which is estimated to reduce life expectancy in the region by an additional six months.
Chart 1 | The chart shows the annual PM2.5 concentrations in the top 25 most polluted countries and other select ones.
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Bangladesh, India, Nepal, and Pakistan, where 22.9% of the global population lives, are the most polluted countries in the world (Chart 1). In Bangladesh, the most polluted country in 2021, people potentially lost an average of 6.8 years of life due to air pollution not meeting the WHO guideline. In contrast, the average person from the U.S. lost just 3.6 months. Notably, China stands out due to its success in reducing pollution by a staggering 42.3% from 2013 to 2021 and extending the average life expectancy of its population by 2.2 years. This reduction can be attributed to the country’s policy initiatives to combat pollution in 2014.
Chart 2 | The chart shows the top 5 threats to life expectancy in India.
In India, the second-most polluted country in the world in 2021, particulate pollution is the greatest threat to human health (Chart 2). Data reveal a further rise in PM2.5 pollution from 56.2 μg/m3 in 2020 to 58.7 μg/m3 in 2021, exceeding the WHO guideline by more than 10 times.
The average Indian resident is set to lose 5.3 years of life expectancy if the WHO guideline remains unmet. In contrast, cardiovascular diseases reduce the average Indian’s life expectancy by about 4.5 years, while child and maternal malnutrition reduces it by 1.8 years.
Chart 3 | The chart shows the most polluted States in India and the potential life expectancy loss if pollution levels do not meet the WHO guideline.
In Delhi, the world’s most polluted city, 18 million people could lose 11.9 years of life expectancy relative to the WHO guideline and 8.5 years of life expectancy relative to the national guideline if current pollution levels persist.
Chart 4 | The chart shows the annual average PM2.5 concentrations in India, the northern plains, and all other regions.
The northern plains, home to over half a billion people and 38.9% of India’s population is the most polluted region. The northern plains include the States and Union Territories of Bihar, Chandigarh, Delhi, Haryana, Punjab, Uttar Pradesh, and West Bengal. In the northern plains, the average resident is set to lose about 8 years of life expectancy if pollution levels persist and policies do not succeed in reducing pollution to levels as prescribed by the WHO.
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Pollution, once concentrated in the northern region, has spread to other parts of the country over the last two decades. For instance, in Maharashtra and Madhya Pradesh, which have a combined population of 204.2 million, pollution has surged by 76.8% and 78.5%, respectively, since 2000, causing a loss of an additional 1.8 years to 2.3 years of life expectancy compared to 2000 levels.
AQLI’s life expectancy calculations are based on a pair of peer-reviewed studies, Chen et al. (2013) and Ebenstein et al. (2017), co-authored by Michael Greenstone. These studies compared two population subgroups exposed to different levels of particulate air pollution. This method effectively isolated the impact of particulate air pollution from other health factors. Ebenstein et al. found that sustained exposure to an additional 10 μg/m3 of PM2.5 reduces life expectancy by 0.98 years.
Source: Air Quality Life Index Annual Update for 2023 published by Michael Greenstone and Christa Hasenkopf of the University of Chicago
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