Bengaluru Mar 26, 2019, (Research Matters):
Air pollution is responsible for an estimated 7 million deaths each year worldwide, and more than a million die due to it in India. Burning fossil fuels and biomass, agriculture and industrial activities release harmful greenhouse gases and tiny particles suspended in the air. These emissions not only result in global warming but are hazardous to our health and disturb the water cycle, reducing rainfall and causing droughts. Eliminating the use of fossil fuels is touted to be an obvious way to reduce air pollution. However, what exact difference can it make?
A new study by an international team of researchers has pegged the number of avoidable deaths due to fossil fuel-related air pollution at 3.6 million. That is, if the world stopped using fossil fuels, we could save as many lives in the world, with about 692,000 in India and 1.5 million in China. Besides, the study also found that getting rid of air pollution caused by all human activities could avoid up to 5.5 million deaths worldwide. The findings of the study have been published in the Proceedings of the National Academy of Sciences.
The researchers used a climate model to calculate the impact of air pollution on public health and the water cycle. It took into account emissions, the chemistry between different states of the pollutants and other phenomena that influence the atmosphere. The researchers calculated the concentrations of ozone and particulate matter smaller than 2.5 micrometre (PM2.5) to estimate their impact on public health and climate in a hypothetical scenario where there is zero emission due to fossil fuels, and significantly reduced levels of pollutants released due to other activities.
The study details a comprehensive country-wise estimate of preventable deaths due to fossil fuels and other human activities. Human activities cause about 2.2 million deaths in China and 1.1 million deaths in India, and they are preventable, says the study. The two countries recorded 61.9 million and 55 million years of lost life due to air pollution. Among the other countries, the USA, Russia and Bangladesh had significant preventable deaths caused due to air pollution.
Mortality Rates due to air pollution [Data source].
Controlling the dominant cause of air pollution, which is different in different countries, fetched the most health benefits.
“The phaseout of fossil energy emissions has relatively larger health gains in North America than in South Asia and Africa. The latter regions can benefit greatly from controlling residential energy use and biomass burning, and in Europe and East Asia, agricultural emissions are important” say the researchers.
Avoidable mortality from anthropogenic air pollution (dark red indicates high avoidable mortality rates). Credit: Image courtesy of the Max Planck Institute for Chemistry.
Avoidable air pollution mortality from fossil fuel use (dark red indicates high avoidable mortality rates). Credit: Image courtesy of the Max Planck Institute for Chemistry.
Unlike previous studies, which are based on the pathways adopted by the Intergovernmental Panel on Climate Change (IPCC) regarding the various possibilities of phasing out fossil fuels, the current study considers wiping out fossil fuels by 2050. It also analysed the chemical effect of air pollution on the dust particles. The researchers say that wiping out fossil fuels could help achieve the target of the Paris Agreement, which is to limit the average temperature rise to 2 °C higher than pre-industrial levels.
Aerosols, which are minute particles suspended in the atmosphere, absorb the sunlight reaching the Earth and thus limiting evaporation and rainfall. Eliminating such emissions caused by all human activities would result in increased rainfall and repair the disturbed water cycle, the study found.
“Because aerosols affect the hydrologic cycle, removing the anthropogenic emissions in the model increases rainfall by 10–70% over densely populated regions in India and 10–30% over northern China, and by 10–40% over Central America, West Africa, and the drought-prone Sahel, thus contributing to water and food security”, say the authors.
In India, lung cancer, pulmonary infections, heart diseases and other non-communicable diseases caused by air pollution, are the leading causes of death. In cases where the illnesses are not fatal, they reduce the life expectancy by 2.9 years globally on an average. Hence, steps to control air pollution can impact public health and climate immensely.
“Here we stress that a complete phase-out of fossil fuels, and accompanying reductions of other anthropogenic emissions, will be needed to reverse the major impacts on public health, regional climate, water supply, and food production”, say the authors, talking about the importance of the study.