Phasing out fossil fuels could save millions of lives

Air pollution continues to be a leading public health risk. Previous estimates of the attributable mortality burden varied significantly between studies, primarily due to differences in the exposure-response relationships and the causes of death included. Furthermore, only a few global studies attributed mortality to specific air pollution sources. In a new study, the research team led by Jos Lelieveld and Andrea Pozzer from the Max Planck Institute for Chemistry and Andy Haines from the London School of Hygiene & Tropical Medicine assesses the consequences of a fossil fuel phaseout for disease-specific and all-cause mortality through the concomitant effects of air pollution.

The researchers find that most (52%) of the mortality burden is related to cardiometabolic conditions, particularly ischaemic heart disease that can cause heart attacks (30%). Stroke and chronic obstructive pulmonary disease both account for about 16%. About 20% is undefined, with arterial hypertension, diabetes mellitus, and neurodegenerative diseases possibly implicated.

"We estimate that 5.13 million excess deaths per year globally are attributable to ambient air pollution from fossil fuel use and therefore could potentially be avoided by phasing out fossil fuels," states atmospheric chemist Jos Lelieveld, director at the Max Planck Institute for Chemistry. "This corresponds to 82% of the maximum number of air pollution deaths that could be averted by controlling all anthropogenic emissions."

The new results were accomplished by applying a new relative risk model which optimizes the exposure-response relationship throughout the global range of ambient exposure levels. In addition, estimates of cause-specific and all-cause mortality due to long-term exposure to particulate matter (PM2.5) and ozone (O3) are attributed to pollution sources in this study.

Study design: Atmospheric modelling method distinguishes source categories The scientists developed a data-constrained global atmospheric modelling method to compute gaseous and particulate air pollutants and attributed them to source categories. The atmospheric model was used to calculate the fractional changes in PM2.5 related to emission sectors based on computer simulations in which source categories have been sequentially switched off.

"Our model calculated fractional changes were then applied to the high-resolution observational particulate pollution data to determine exposure reductions according to four emission scenarios," explains Andrea Pozzer. The first scenario assumes that all fossil fuel-related emission sources are phased out. The second and third, "quarter way" and "half way" scenarios assume that 25 per cent and 50 per cent of the exposure reduction towards the fossil phaseout are realised, respectively. Finally, the fourth removes all anthropogenic sources for reference, thus only accounting for natural sources such as aeolian dust, marine and terrestrial biosphere emissions, and natural wildfires. Since the responses are not strongly non-linear, the team of scientists concludes that fossil fuel-related emission reductions at all levels of air pollution can decrease the number of attributable deaths substantially.

"Ambient air pollution would no longer be a leading environmental health risk factor if the use of fossil fuels were superseded by equitable access to clean sources of renewable energy," emphasizes epidemiologist Andy Haines from the London School of Hygiene & Tropical Medicine. "This study provides new evidence to motivate rapid fossil fuel phaseout." Phasing out fossil fuels is a remarkably effective health-improving and life-saving intervention and a major co-benefit of the United Nations' goal of climate neutrality by 2050.

Air pollution continues to be a leading public health risk. Previous estimates of the attributable mortality burden varied significantly between studies, primarily due to differences in the exposure-response relationships and the causes of death included. Furthermore, only a few global studies attributed mortality to specific air pollution sources. In a new study, the research team led by Jos Lelieveld and Andrea Pozzer from the Max Planck Institute for Chemistry and Andy Haines from the London School of Hygiene & Tropical Medicine assesses the consequences of a fossil fuel phaseout for disease-specific and all-cause mortality through the concomitant effects of air pollution.

The researchers find that most (52%) of the mortality burden is related to cardiometabolic conditions, particularly ischaemic heart disease that can cause heart attacks (30%). Stroke and chronic obstructive pulmonary disease both account for about 16%. About 20% is undefined, with arterial hypertension, diabetes mellitus, and neurodegenerative diseases possibly implicated.

"We estimate that 5.13 million excess deaths per year globally are attributable to ambient air pollution from fossil fuel use and therefore could potentially be avoided by phasing out fossil fuels," states atmospheric chemist Jos Lelieveld, director at the Max Planck Institute for Chemistry. "This corresponds to 82% of the maximum number of air pollution deaths that could be averted by controlling all anthropogenic emissions."

The new results were accomplished by applying a new relative risk model which optimizes the exposure-response relationship throughout the global range of ambient exposure levels. In addition, estimates of cause-specific and all-cause mortality due to long-term exposure to particulate matter (PM2.5) and ozone (O3) are attributed to pollution sources in this study.

Study design: Atmospheric modelling method distinguishes source categories

The scientists developed a data-constrained global atmospheric modelling method to compute gaseous and particulate air pollutants and attributed them to source categories. The atmospheric model was used to calculate the fractional changes in PM2.5 related to emission sectors based on computer simulations in which source categories have been sequentially switched off.

"Our model calculated fractional changes were then applied to the high-resolution observational particulate pollution data to determine exposure reductions according to four emission scenarios," explains Andrea Pozzer. The first scenario assumes that all fossil fuel-related emission sources are phased out. The second and third, "quarter way" and "half way" scenarios assume that 25 per cent and 50 per cent of the exposure reduction towards the fossil phaseout are realised, respectively. Finally, the fourth removes all anthropogenic sources for reference, thus only accounting for natural sources such as aeolian dust, marine and terrestrial biosphere emissions, and natural wildfires. Since the responses are not strongly non-linear, the team of scientists concludes that fossil fuel-related emission reductions at all levels of air pollution can decrease the number of attributable deaths substantially.

"Ambient air pollution would no longer be a leading environmental health risk factor if the use of fossil fuels were superseded by equitable access to clean sources of renewable energy," emphasizes epidemiologist Andy Haines from the London School of Hygiene & Tropical Medicine. "This study provides new evidence to motivate rapid fossil fuel phaseout." Phasing out fossil fuels is a remarkably effective health-improving and life-saving intervention and a major co-benefit of the United Nations' goal of climate neutrality by 2050.