A high‐resolution ammonia emission inventory in China

TLDR

Ammonia in the atmosphere influences tropospheric chemistry and climate, and China—owing to its vast agriculture, animal population, and fertilizer use—emits large amounts of NH₃, yet emission estimates remain uncertain. This study compiled a high‑resolution 1 km × 1 km NH₃ emission inventory for China to serve as input for atmospheric models. Emissions were estimated by incorporating native experimental data and parameterizing emission factors with ambient temperature, soil acidity, and other environmental variables. The inventory estimates total NH₃ emissions of 9.8 Tg in 2006, dominated by livestock excreta (5.3 Tg) and fertilizer use (3.2 Tg), with the highest rates in Central and Southwest China and seasonal peaks in spring and summer.

Abstract

The existence of gas‐phase ammonia (NH 3 ) in the atmosphere and its interaction with other trace chemical species could have a substantial impact on tropospheric chemistry and global climate change. China is a large agricultural country with an enormous animal population, tremendous nitrogen fertilizer consumption and, consequently, a large emission of NH 3 . Despite the importance of NH 3 in the global nitrogen (N) cycle, considerable inaccuracies and uncertainty exist regarding its emission in China. In this study, a comprehensive NH 3 emission inventory was compiled for China on a 1 km × 1 km grid, which is suitable for input to atmospheric models. We attempted to estimate NH 3 emissions accurately by taking into consideration as many native experiment results as possible and parameterizing the emission factors (EFs) by the ambient temperature, soil acidity and other factors. The total NH 3 emission in China was approximately 9.8 Tg in 2006. The emission sources considered included livestock excreta (5.3 Tg), fertilizer application (3.2 Tg), agricultural soil (0.2 Tg), nitrogen‐fixing plants (0.05 Tg), crop residue compost (0.3 Tg), biomass burning (0.1 Tg), urine from rural populations (0.2 Tg), chemical industry (0.2 Tg), waste disposal (0.1 Tg) and traffic (0.1 Tg). The regions with the highest emission rates are located in Central and Southwest China. Seasonally, the peak ammonia emissions occur in spring and summer.