Study analyses air quality impacts of widespread dietry change
New research by a European-wide team of academics has examined how widespread changes in diet to plant-based flexitarian, vegetarian, and vegan diets could lead to meaningful reductions in air pollution.
Food production – particularly when animals are involved – is a major source of methane and ammonia emissions which contribute to air pollution through the formation of particulate matter and ground-level ozone.
The problematic involvement of animals is widespread, as manure, when used as a fertiliser leads to the formation of ammonium salts which contributes to the concentration of air-borne PM2.5. A better known problem is the methane produced by ruminant animals. Methane contributes to the formation of ground-level ozone which affects the human respiratory system under prolonged exposure.
The researchers approached the subject from four angles:
Firstly, they used a global agriculture-economic model to estimate what impacts dietary changes would have on agricultural production and the associated emissions of precursors to air pollutants, including ammonia and methane.
Secondly, they used an air-quality model to estimate what impacts changes in ammonia and methane would have on the concentration of PM2.5 and ground-level ozone.
Thirdly they estimated the health impacts of changes in air pollution.
Finally, they used economic models to quantify the monetary value of the health benefits and the potential impacts on labour productivity.
The dietary changes were assumed to occur over the current decade and show the associated impacts by the year 2030
The results found that the globally averaged exposure to PM2.5 was reduced by 3% for flexitarian diets, 6% for vegetarian diets, and 7% for vegan diets while nd the exposure to ozone was reduced by 2%, 3%, and 4% respectively.
The health benefits varied across regions. Europe, where intensive agriculture is combined with high population density, saw the greatest relative reductions (9–21% fewer premature deaths from PM2.5 and ozone across the diet scenarios), followed by North America (12–18%), and Developed Asia-Pacific (10–18%).
The economic benefits of the improvement in air quality were particularly large for countries with high economic output, including those in Eastern Asia (increase in economic output of 1.3–3.2% of GDP), North America (0.6–0.8%), Developed Asia-Pacific (0.4–0.6%), and Europe (0.3–0.6%).
