Mitigation of agricultural NH3 emissions reduces PM2.5 pollution in China: A finer scale analysis

Ammonia (NH3) emissions have been linked to the formation of fine particulate matter (PM2.5) in the air, and PM2.5 pollution has been shown to damage environment quality and public health on a global scale. Current management practices can reduce NH3 emissions significantly. However, reduction effects of these measures are only considered for specific source or chain. Potentials of NH3 emissions reduction from the whole agricultural systems by integrating current management measures and how agricultural NH3 emissions affect PM2.5 pollution by these integrated measures at the provincial level in China is poorly quantified. Thus, we calculated the potential to mitigate NH3 emissions under different integrated reduction measures and assessed the mitigation effect on PM2.5 pollution at the provincial level in China. Furthermore, costs for agricultural NH3 emission abatement and health benefits from reducing PM2.5 pollution by agricultural NH3 control were evaluated. We found that total agricultural NH3 emissions in China was 12.5 Tg N in 2017, which can be reduced by 74% if highly effective reduction techniques are integrated applying, with the potential to reduce PM2.5 pollution from 43 to 28 μg m−3. The cost to implement the mitigation scenarios ranged from 57 to 999 billion ¥, while the health benefits from PM2.5 pollution control increased from 1471 to 1768 billion ¥ when NH3 emissions were reduced from 47 to 74%. The benefit-to-cost ratio was much higher in provinces/cities with highly developed economies and a high population density than those with less developed economies.