Four decades of full-scale nitrous oxide emission inventory in China.

China is among the top nitrous oxide (NO)-emitting countries, but existing national inventories do not provide full-scale emissions including both natural and anthropogenic sources. We conducted a four-decade (19802020) of comprehensive quantification of Chinese NO inventory using empirical emission factor method for anthropogenic sources and two up-to-date process-based models for natural sources. Total NO emissions peaked at 2287.4 (1774.82799.9) Gg NO yr in 2018, and agriculture-developed regions, like the East, Northeast, and Central, were the top NO-emitting regions. Agricultural NO emissions have started to decrease after 2016 due to the decline of nitrogen fertilization applications, while, industrial and energetic sources have been dramatically increasing after 2005. NO emissions from agriculture, industry, energy, and waste represented 49.3%, 26.4%, 17.5%, and 6.7% of the anthropogenic emissions in 2020, respectively, which revealed that it is imperative to prioritize NO emission mitigation in agriculture, industry, and energy. Natural NO sources, dominated by forests, have been steadily growing from 317.3 (290.3344.1) Gg NO yr in 1980 to 376.2 (335.5407.2) Gg NO yr in 2020. Our study produces a Full-scale Annual NO dataset in China (FAN2020), providing emergent counting to refine the current national NO inventories.