PM2.5 exposure reducing lifespan in Mumbai by 3.7 years: AQLI
Exposure to PM2.5 — respirable particulate matter less than 2.5 micrometres in diameter — is potentially reducing the lifespan of Mumbai citizens by an average of 3.7 years, suggests a recently updated index known as the Air Quality Life Index (AQLI) by the University of Chicago’s Energy Policy Institute (EPIC).
The index also shows that the average annual concentration of PM2.5 in Mumbai increased from 43.4ug/m3 to 47.9ug/m3 from 2016 to 2019. Accordingly, the outcome for life expectancy has been unfavourable and the average reduction in a single citizen’s lifespan has also increased from 3.3 years in 2016 to 3.7 years in 2019. This is based on AQLI’s epidemiological assumption that life expectancy is reduced by 0.98 years for every 10μg/m3 of sustained exposure to particulate matter.
AQLI was first published in 2018, using available data till 2016. The latest instalment in AQLI uses updated air pollution data till 2019 and translates it into impact on life expectancy using an approach similar to that deployed in China, where populations north of Huai River are provided free or subsidised coal for indoor heating in the winter. AQLI is based on a study in which researchers were able to measure the effect of sustained exposure to high levels of pollution on a person’s life expectancy.
As per the updated numbers released on Wednesday, the national average reduction in lifespan due to PM2.5 is 5.9 years in India, while that in Maharashtra is four years. In Pune, exposure to PM2.5 is reducing life expectancy by 4.2 years on an average. Gondia and Bhandara districts in Vidarbha were found to be the most polluted with life expectancy reducing by 5.1 and five years, respectively.
Dr Piyush Goel, pulmonologist with a leading chain of private hospitals in Asia, explained that PM2.5 particles are minute enough to enter the alveoli in human lungs, where the exchange of respiratory gases takes place. “When this alien material, which comes from vehicles, construction and many other sources, enters the alveoli, the body begins to secrete mediating enzymes which cause destruction of lung tissue,” he said. These particles can even be tiny enough to pass through the alveoli and enter the blood stream, from where they get deposited in other organs, making them degenerate prematurely.
“On the whole, inhalation of PM2.5 leads to a gradual degeneration of various parts of the body, which results in accelerated aging. This may be one reason why we’re seeing younger people having chronic obstructive pulmonary disorder (COPD), heart attacks and similar ailments which were earlier majorly seen in older age groups,” Dr Goel said.
Dr Lancelot Pinto, pulmonologist and epidemiologist from Hinduja hospital, emphasised that the link between ambient air pollution and life expectancy has been reported in multiple studies and guides WHO guidelines. “Air pollution has a strong link with respiratory disease through its association with diseases such as chronic obstructive pulmonary disease (COPD), which is the third leading cause of death in India, as well as asthma and other underlying respiratory diseases. There is also a link with cardiovascular diseases through its effects on heart rate, blood pressure. It [AQLI] is important for policymakers because the focus on health is often on helping to build healthcare infrastructure, which addresses disease once it has occurred (tertiary prevention). Primary prevention might yield much higher returns, by promoting health, and preventing, rather than curing disease.”
In a statement released on Wednesday, EPIC noted that India’s high levels of air pollution have expanded geographically over time. “Compared to a couple of decades ago, particulate pollution is no longer a feature of the Indo-Gangetic plains alone. Pollution has increased so much in the states of Maharashtra and Madhya Pradesh. For example, the average person in those states is now losing an additional 2.5 to 2.9 years of life expectancy, relative to early 2000s,” it said.
SN Tripathi, atmospheric scientist and professor at Indian Institute of Technology-Kanpur who recently led an air pollution study across the Mumbai Metropolitan Region (MMR), said the numbers are plausible, and that the increase in PM pollutants in Mumbai was likely to be due to anthropogenic activities.
“We have always believed that Mumbai, being a coastal city, has a natural defence against air pollution, but now it seems even this has its limitations. In a recent study, we have observed PM2.5 concentrations of up to 100ug/m3 in some locations. The increase in such pollutants is likely to be due to human activity, namely vehicular emissions, construction or industries. Sectoral policies to mitigate emissions from these sources are the appropriate response. For example, a policy to increase adoption of cleaner transport and fuel would help bring down pollutants from vehicles and improve human health to a degree,” he said.