China's air quality has improved significantly through a combination of short-term and long-term emission control measures. Short-term measures during major international events reduced PM2.5 concentrations but led to rebounds after the events. Long-term policies, such as the Air Pollution Prevention and Control Action Plan, reduced PM2.5 by 54% in Beijing and nitrogen deposition by 23% in China from 2012 to 2020. These policies, combined with short-term measures, have improved air quality sustainably. However, challenges remain, including increased ammonia concentrations, transboundary pollution, and the complexity of achieving reduction targets under climate change scenarios. China's rapid economic growth has led to severe environmental issues, prompting public demand for improved air quality. Since the 1980s, China has focused on controlling sulfur dioxide and acid rain, and since 2010, on reactive nitrogen pollution and PM2.5. During major events, short-term measures like industrial shutdowns and vehicle restrictions reduced pollutants but had temporary effects. Long-term policies, such as the 3-Year Action Plan, have led to significant reductions in emissions and improved air quality. Short-term measures had immediate effects on PM2.5 and nitrogen deposition, but long-term policies are more effective for sustained improvements. However, the effectiveness of short-term measures is limited by rebound effects. Long-term policies have shown greater success in reducing PM2.5 and nitrogen deposition, but challenges remain in controlling ammonia and transboundary pollution. The study highlights the trade-off between short-term and long-term measures, emphasizing the need for combined strategies. Long-term policies have reduced nitrogen deposition by 19% in China from 2012 to 2020, with a strong correlation between nitrogen emissions and deposition. However, ammonia emissions have increased, and climate change complicates pollution control. Regional differences in nitrogen deposition and emissions show that North China has seen more significant reductions, while other regions have seen less. Agricultural sources account for over 80% of ammonia emissions, requiring targeted control measures. The study also highlights the need for regional cooperation and sustainable practices to address pollution. Future air quality improvement depends on long-term policies and technological innovation. The study suggests that combining short-term and long-term measures is essential for sustainable air quality improvement, balancing economic and environmental goals. Policies should focus on reducing emissions from agriculture, industry, and transportation, while promoting sustainable practices and regional cooperation.China's air quality has improved significantly through a combination of short-term and long-term emission control measures. Short-term measures during major international events reduced PM2.5 concentrations but led to rebounds after the events. Long-term policies, such as the Air Pollution Prevention and Control Action Plan, reduced PM2.5 by 54% in Beijing and nitrogen deposition by 23% in China from 2012 to 2020. These policies, combined with short-term measures, have improved air quality sustainably. However, challenges remain, including increased ammonia concentrations, transboundary pollution, and the complexity of achieving reduction targets under climate change scenarios. China's rapid economic growth has led to severe environmental issues, prompting public demand for improved air quality. Since the 1980s, China has focused on controlling sulfur dioxide and acid rain, and since 2010, on reactive nitrogen pollution and PM2.5. During major events, short-term measures like industrial shutdowns and vehicle restrictions reduced pollutants but had temporary effects. Long-term policies, such as the 3-Year Action Plan, have led to significant reductions in emissions and improved air quality. Short-term measures had immediate effects on PM2.5 and nitrogen deposition, but long-term policies are more effective for sustained improvements. However, the effectiveness of short-term measures is limited by rebound effects. Long-term policies have shown greater success in reducing PM2.5 and nitrogen deposition, but challenges remain in controlling ammonia and transboundary pollution. The study highlights the trade-off between short-term and long-term measures, emphasizing the need for combined strategies. Long-term policies have reduced nitrogen deposition by 19% in China from 2012 to 2020, with a strong correlation between nitrogen emissions and deposition. However, ammonia emissions have increased, and climate change complicates pollution control. Regional differences in nitrogen deposition and emissions show that North China has seen more significant reductions, while other regions have seen less. Agricultural sources account for over 80% of ammonia emissions, requiring targeted control measures. The study also highlights the need for regional cooperation and sustainable practices to address pollution. Future air quality improvement depends on long-term policies and technological innovation. The study suggests that combining short-term and long-term measures is essential for sustainable air quality improvement, balancing economic and environmental goals. Policies should focus on reducing emissions from agriculture, industry, and transportation, while promoting sustainable practices and regional cooperation.