The food we eat, the air we breathe: a review of the fine particulate matter-induced air quality health impacts of the global food system

The global food system is essential for the health and wellbeing of society, but is also a major cause of environmental damage. Some impacts, such as on climate change, have been the subject of intense recent inquiry, but others, such as on air quality, are not as well understood. Here, we systematically synthesize the literature to identify the impacts on ambient PM ₂. 5 (particulate matter with diameter ⩽2. 5 μ m), which is the strongest contributor to premature mortality from exposure to air pollution. Our analysis indicates that the life-cycle of the global food system (pre-production, production, post-production, consumption and waste management) accounts for 58% of anthropogenic, global emissions of primary PM ₂. 5, 72% of ammonia (NH ₃), 13% of nitrogen oxides (NO ₓ), 9% of sulfur dioxide (SO ₂), and 19% of non-methane volatile organic compounds (NMVOC). These emissions result in at least 890 000 ambient PM ₂. 5 -related deaths, which is equivalent to 23% of ambient PM ₂. 5 -related deaths reported in the Global Burden of Disease Study 2015. Predominant contributors include livestock and crop production, which contribute >50% of food-related NH ₃ emissions, and land-use change and waste burning, which contribute up to 95% of food-related primary PM ₂. 5 emissions. These findings are largely underestimated given the paucity of data from the post-production and consumption stages, total underestimates in NH ₃ emissions, lack of sector-scale analysis of PM ₂. 5 -related deaths in South America and Africa, and uncertainties in integrated exposure-response functions. In addition, we identify mitigation opportunities—including shifts in food demand, changes in agricultural practices, the adoption of clean and low-energy technologies, and policy actions—that can facilitate meeting food demand with minimal PM ₂. 5 impacts. Further research is required to resolve sectoral-scale, region-specific contributions to PM ₂. 5 -related deaths, and assess the efficiency of mitigation strategies. Our review is positioned to inform stakeholders, including scientists, engineers, policymakers, farmers and the public, of the health impacts of reduced air quality resulting from the global food system.