Marginal decrease in PM2.5 levels in 2022 added 1 year to avg life expectancy
AQLI is a pollution index that quantifies the causal relationship between long-term human exposure to air pollution and life expectancy
A mere 10 microgram — a strand of human hair weighs 600 microgram — decline in the concentration of PM2.5 (particulate matter with a size of 2.5 micrometres or smaller) in 2022 has added a year to the average Indian’s life expectancy, according to the latest edition of the annual Air Quality Life Index (AQLI) report released by the Energy Policy Institute at the University of Chicago (EPIC).
The report further suggested that the drop in PM 2.5 concentrations in 2022 over South Asia may be linked to meteorological causes — such as above normal rainfall. In India PM2.5 concentrations dropped from 51.3 µg/m³ in 2021 to 41.4 µg/m³ in 2022, as per satellite data used by AQLI. Rainfall in the four-month season of the southwest monsoon in India (June-September) was categorised above normal, and came in at 106% over the long period average of 87mm, the average rainfall between 1971 and 2020.
But the improvement is cold comfort — all of India’s 1.4 billion people continue to live in areas where the annual average particulate pollution level exceeds the World Health Organisation guideline of 5µg/m³. And 42.6% of the population lives in areas that exceed the country’s own national air quality standard of 40 µg/m³, the report added.
AQLI is a pollution index that quantifies the causal relationship between long-term human exposure to air pollution and life expectancy. The life expectancy calculations made by AQLI are based on a pair of peer-reviewed studies. By comparing two subgroups of the population that experienced prolonged exposure to different levels of particulate air pollution, the studies were able to plausibly isolate the effect of particulate air pollution from other factors that affect health.
If all of India were to reduce particulate pollution to meet the WHO benchmark, Indians would live 3.6 years longer, with residents of Delhi, one of the most polluted places on Earth seeing the maximum benefits, an incremental 7.8 years of life expectancy. In North 24 Parganas—the country’s second most populous district—residents would gain 3.6 years of life expectancy, the report added. Residents of Uttar Pradesh would gain 5.9 years on average.
Those gains, though, are in the realm of the hypothetical. In the real world, and in the most polluted region of the country—the Northern Plains/Indo-Gangetic Plains region—540.7 million people or 38.9% of India’s population are on track to lose 5.4 years of life expectancy on average relative to the WHO guideline and 1.9 years relative to the national standard, if current pollution levels persist.
Pollution concentrations were slightly lower in 2022 globally. If the world were to permanently reduce fine particulate pollution (PM2.5) to meet the World Health Organization’s (WHO) guideline, the average person would add 1.9 years onto their life expectancy—or a combined 14.9 billion life-years saved worldwide.
“This data makes clear that particulate pollution is the world’s greatest external risk to human health. Its impact on life expectancy is comparable to that of smoking, more than 4 times that of high alcohol use, more than 5 times that of transport injuries like car crashes, and more than 6 times that of HIV/AIDS. Yet, the pollution challenge worldwide is vastly unequal, with people living in the most polluted places on earth breathing air that is six times more polluted than the air breathed by those living in the least polluted places—and seeing their lives cut short by 2.7 years more because of it,” the report said.
Michael Greenstone, the Milton Friedman Distinguished Service Professor in Economics and creater of AQLI highlighted the vast inequalities in how air pollution impacts people.
“While air pollution remains a global problem, its largest impacts are concentrated in a relatively small number of countries—cutting lives short several years in some places and even more than 6 years in some regions,”he said. “All too often, high pollution concentrations reflect low ambition in setting policy or a failure to successfully enforce existing policies.”
In 2019, India launched its National Clean Air Programme (NCAP) aiming to reduce particulate pollution by 20-30% nationally relative to 2017 levels by 2024 and focused on 102 cities that were not meeting India’s national annual PM2.5 standard, termed “non-attainment cities.” But a Centre for Science and Environment (CSE) assessment last month revealed that road dust mitigation has been the primary focus of NCAP, which was launched in 2019 as the first such effort to set clean air targets for 131 polluted cities and to reduce particulate pollution nationally, with much lower funding for combustion sources that emit pollutants.
China has managed to reduce air pollution by 41% since 2013, the year before the country began a “war against pollution” according to EPIC.
Due to these improvements, the average Chinese citizen can expect to live 2 years longer, provided the reductions are sustained. China still accounts for 20% of the world’s air pollution burden. The average person in China could see their life expectancy increase by 2.3 years more if the country met the WHO guideline for pollution.
Americans are exposed to 67.2% less particulate pollution than they would have been in 1970—prior to the passage of the Clean Air Act—and they’re living 1.5 years longer because of it. Yet, 94% of the country still doesn’t meet the WHO’s guideline (5 µg/m3). This year, the country’s Environmental Protection Agency implemented a more stringent standard (10 µg/m3) for particulate pollution, gaining 1.9 million total life years if this standard is met.
