Paradigm shift in aerosol chemical composition over regions downwind of China.

摘要: A rapid decrease in PM2.5 concentrations China has been observed response to the enactment of strong emission control policies. From 2012 2017, total emissions SO2 and NOx from decreased by approximately 63% 24%, respectively. Simultaneously, decreases concentration Japan have since 2014, proportion stations that satisfy environmental standard (daily, 35 µg/m3; annual average, 15 µg/m3) increased 37.8% fiscal year (FY) 2014 (April March 2015) 89.9% FY 2017. However, quantitative relationship between improvement downwind regions is not well understood. Here, we (1) quantitatively evaluate impacts Chinese improvements on areas using source/receptor analysis with a chemical transport model, (2) show these reductions improved both its regions, but difference reduction rates led greater production nitrates (e.g., NH4NO3) due imbalance ammonia–nitric acid–sulfuric acid–water system. Observations clean remote island western numerical modeling confirmed this paradigm shift.