A study provides new arguments in favour of rapidly phasing out the use of fossil fuels. An international team of scientists determined the burden of air pollution and its effects on health. The allocation of total mortality and disease-specific deaths to specific emission sources shows that around five million attributable deaths per year could be avoided worldwide by phasing out the use of fossil fuels. The team used both an updated atmospheric chemistry model and a newly developed model to determine the relative health risk, as well as current satellite data on particulate matter.
The study by researchers from the Max Planck Institute for Chemistry (Germany), the London School of Hygiene & Tropical Medicine (United Kingdom), the University of Washington (USA), the Barcelona Institute for Global Health (Spain) and the Mainz University Medical Centre (Germany), a partner site ofthe DZHK, was published yesterday in the British Medical Journal (BMJ), a renowned medical journal.
Air pollution remains one of the greatest threats to public health. Previous estimates of the attributable mortality burden - known as excess mortality - vary considerably, primarily due to different assumptions about the exposure-effect relationship and the causes of death considered. In addition, only a few global studies have attributed mortality to specific sources of air pollution. 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, is now making up for this. The study assesses the impact that phasing out the use of fossil fuels would have on air pollution and thus on disease-specific mortality and overall mortality.
"We estimate that around 5.1 million attributable deaths per year worldwide are due to air pollution from fossil fuel use. These could be avoided by switching to clean, renewable energy sources," explains atmospheric chemist Jos Lelieveld, Director at the Max Planck Institute for Chemistry.
Most of the attributable deaths (52%) are related to cardiovascular diseases. In particular, these are ischaemic heart diseases (30%), which disrupt the blood flow to the heart and can lead to heart attacks. Stroke and chronic obstructive pulmonary disease each account for around 16%, diabetes around 6%. Around 20% were undefined, but are likely to be partly related to high blood pressure and neurodegenerative diseases such as Alzheimer's and Parkinson's.
The results are based on data from the 2019 Global Burden of Disease Study, satellite-based particulate matter and population data and relative risk modelling, which depicts the relationship between exposure to pollutants and health effects. In addition, the disease-specific mortality rate and overall mortality attributable to long-term exposure to particulate matter (PM2.5) and ozone (O3) are attributed to the emission sources.
"Air pollution causes and exacerbates cardiovascular disease, demonstrating in particular the susceptibility of the cardiovascular system to particulate matter. It is therefore of utmost importance to recognise air pollution as a major cardiovascular risk factor, for example in the ESC and AHA/ACC guidelines for prevention, ischaemic heart disease and stroke," explains cardiologist and co-author Thomas Münzel from the Mainz University Medical Centre.
Study design: Atmospheric modelling method divides air pollution into categories
The basis for the calculation of gaseous and particulate air pollutants is a data-supported global atmospheric model. By switching off the various sources of air pollution one after the other using computer simulations, the scientists determined the proportional changes in PM2.5 values for each specific emission."For four different scenarios, we determined how much emissions caused by fossil fuels would be reduced," explains Andrea Pozzer, group leader at the Max Planck Institute for Chemistry in Mainz, Germany. In the first scenario, the sources are gradually switched off. The second and third scenarios assume a 25 and 50 per cent reduction respectively. Finally, according to the fourth scenario, there are no anthropogenic emissions at all, only natural emissions such as desert dust and soot from natural forest fires.
The scenarios show that the relationship between exposure to pollutants and health effects is almost linear. From this, the team of scientists concludes that any reduction in emissions from fossil fuels can significantly reduce the number of attributable deaths.
"If fossil fuels were replaced by equitable access to clean renewable energy sources, air pollution would no longer be a significant environmental health risk," emphasises epidemiologist Andy Haines, Professor of Environmental Change and Public Health at the London School of Hygiene & Tropical Medicine. "Given the Paris Climate Agreement's goal to be carbon neutral by 2050, replacing fossil fuels with renewable energy sources would bring rapid public health and climate benefits."
Original publication: Air pollution deaths attributable to fossil fuels: observational and modelling study (Lelieveld et al., 2023)
Source: press release MPI chemistry