Life-cycle management of nitrogen fertilizer systems in China reduces greenhouse gas emissions and nitrogen pollution while improving air quality

Nitrogen fertilizers sustain food security but complicate climate and air-pollution mitigation. Greenhouse gas (GHG) emissions arise mainly from energy-intensive production, whereas reactive nitrogen (Nr) losses occur largely during application. Here, we develop an integrated life-cycle framework that links fertilizer production and cropland nitrogen budgets and apply it to China for 1990–2020. Expanding fertilizer exports widens the disconnect between production and application. In 2020, the system emitted 432 Tg CO 2 eq and 3.3 Tg Nr, increasing PM 2.5 concentrations by up to 5.2 μg m −3 across central and eastern China. Production accounted for 77% of GHG emissions, while application caused 92% of Nr losses. Coordinated management could reduce GHG emissions by 65% and Nr losses by 52% by 2050, lower PM 2.5 concentrations by 1.5 μg m −3 , and avoid approximately 195,000 premature deaths. These results show that life-cycle coordination is essential for unlocking mitigation synergies in fertilizer systems.