Ammonia transfers through interprovincial agricultural trade and their health burden implications in China

The spatial mismatch between agricultural resources and market demand across China creates significant challenges for food security and environmental management. Although interprovincial agricultural trade can alleviate regional food supply pressures, substantial uncertainties persist regarding the associated ammonia (NH 3 ) emission transfers and their impacts on air quality and human health. Here we fill this gap using a linear programming model to simulate interprovincial trade flows of 26 individual agricultural products, combined with high-resolution NH 3 emission inventories and air quality simulation. We found that interprovincial trade-related NH 3 emissions reached 2.94 Tg in 2019, accounting for 28.1% of total agricultural NH 3 emission, with predominant transfers from eastern and southern China to northern and central China. These trade-related NH 3 emissions contributed 2.6 μ g m −3 to annual PM 2.5 concentrations and caused 252 016 associated premature deaths. Mortality response to trade-related NH 3 emissions exhibited spatial heterogeneity across China, driven by regional variations in population density and PM 2.5 sensitivity to NH 3 emissions. Agricultural trade generated disproportionate health impacts, with Central China, Southwest China, North China, and Northeast China collectively receiving a net inflow of 28 776 premature deaths. Our results demonstrate that a cross-provincial ecological compensation mechanism needs to be established to balance agricultural trade’s impact on food security, air quality, and human health.