https://www.bmj.com/content/383/bmj-2023-077784
Read more about this on the Guardian: https://www.theguardian.com/environment/2023/nov/29/air-pollution-from-f...
Results Globally, all cause excess deaths due to fine particulate and ozone air pollution are estimated at 8.34 million (95% confidence interval 5.63 to 11.19) deaths per year. Most (52%) of the mortality burden is related to cardiometabolic conditions, particularly ischaemic heart disease (30%). Stroke and chronic obstructive pulmonary disease both account for 16% of mortality burden. About 20% of all cause mortality is undefined, with arterial hypertension and neurodegenerative diseases possibly implicated. An estimated 5.13 million (3.63 to 6.32) 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. This figure corresponds to 82% of the maximum number of air pollution deaths that could be averted by controlling all anthropogenic emissions. Smaller reductions, rather than a complete phase-out, indicate that the responses are not strongly non-linear. Reductions in emission related to fossil fuels at all levels of air pollution can decrease the number of attributable deaths substantially. Estimates of avoidable excess deaths are markedly higher in this study than most previous studies for these reasons: the new relative risk model has implications for high income (largely fossil fuel intensive) countries and for low and middle income countries where the use of fossil fuels is increasing; this study accounts for all cause mortality in addition to disease specific mortality; and the large reduction in air pollution from a fossil fuel phase-out can greatly reduce exposure.
Conclusions Phasing out fossil fuels is deemed to be an effective intervention to improve health and save lives as part the United Nations' goal of climate neutrality by 2050. Ambient air pollution would no longer be a leading, environmental health risk factor if the use of fossil fuels were superseded by equitable access to clean sources of renewable energy.
Introduction
Global air quality guidelines from World Health Organization (WHO) call attention to the huge toll of air pollution on human health, leading to millions of deaths yearly, comparable to tobacco smoking.1 The 2019 global burden of disease (GBD) study estimated that all forms of air pollution account for about 11.3% of total deaths worldwide for women and 12.2% for men.2 Improvements to air quality contribute to many of the United Nations’ sustainable development goals for 2030, and air pollution is directly mentioned in two targets to achieve these goals.34 Previous studies have suggested that transitioning from fossil fuels to clean, renewable energy sources in the coming decades will help save many lives from air pollution and limit the global mean temperature rise caused by greenhouse gases to below 2°C, thereby meeting the Paris Climate Agreement.567 However, mortality estimates attributable to air pollution and the causes of death vary widely, with few studies estimating the mortality burden from all causes.8 We assess the consequences of a fossil fuel phase-out for disease specific and all cause mortality through the concomitant effects of air pollution. The pace and scale of achievement of such a phase-out will depend on the speed of the global transition towards renewable energy sources. Although technically and economically a fossil fuel phase-out, or at least carbon neutrality, is considered feasible by 2050, the process is hampered by a scarcity of global cooperation on policies involving carbon pricing, government regulations, and investments.9 We did not consider international policies and socioeconomic pathways in this study, however, we aimed to incentivise large, rapid reductions of greenhouse gas emissions by increasing awareness of the public health benefits of concurrent air pollution reductions.
Global health burden studies have attributed four to ten million deaths per year to outdoor (ambient) particulate pollution attributed to PM2.5 (particulate matter with a diameter smaller than 2.5 µm), and attributed 0.3-1.3 million deaths per year to ozone (O3).8 These wide ranges reflect the number of health outcomes accounted for and the relative risk functions used to perform the calculations. Using the 2018 relative risk model that Burnett and colleagues developed for all cause mortality from global PM2.5 exposure,10 along with that from O3, we previously estimated 8.79 million (95% confidence interval 7.11 to 10.41) deaths per year.6
Weichenthal and colleagues refined the exposure-response association and found that the health impacts at low PM2.5 concentrations had generally been underestimated.11 However, Burnett and colleagues’ research, published in 2022, found that attributable mortality for heavily polluted air had been overestimated and provided a model optimised for the entire PM2.5 concentration distribution.12 Countries with either low or high PM2.5 concentrations typically have different emission characteristics, therefore, re-evaluation of the contributions of fossil fuel use and other sources of air pollution is needed.1314 In this article, we apply Burnett and colleagues’ new relative risk FUSION model,12 optimised for health benefits analyses, and we update exposure estimates to PM2.5 and O3. Although climate change due to fossil fuel use may also contribute to mortality, for example, by increasing weather extremes, the present work solely investigates deaths related to air pollution.
