Non-agricultural ammonia emissions in urban China

Abstract. The non-agricultural ammonia (NH₃) emissions in cities have received little attention but could rival agricultural sources in term of the efficiency in PM formation. The starting point for finding credible solutions is to comprehensively establish a city-specific Non-agricultural Ammonia Emission Inventory (NAEI) and identify the largest sources where efforts can be directed to deliver the largest impact. In this paper, I present a NAEI of 113 national key cities targeted on environmental protection in China in 2010, which for the first time covers NH₃ emissions from pets, infants, smokers, green land, and household products. Results show that totally 210 478 Mg, the NH₃ emissions from traffic, fuel combustion, waste disposal, pets, green land, human, and household products are 67 671 Mg, 56 275 Mg, 44 289 Mg, 23 355 Mg, 7509 Mg, 7312 Mg, and 4069 Mg, respectively. The NH₃ emission intensity from the municipal districts ranges from 0.08 to 3.13 Mg km⁻² yr⁻¹, with a average of 0.84 Mg km⁻² yr⁻¹. The high NH₃ emission intensities in Beijing-Tianjin-Hebei region, Yangtze River Delta region and Pearl River Delta region support the view that non-agricultural NH₃ sources play a key role in city-scale NH₃ emissions and thus have potentially important implications for secondary PM formation (ammonium-sulfate-nitrate system) in urban agglomeration of China. Therefore, in addition to current SO₂ and NO_x controls, China also needs to allocate more scientific, technical, and legal resources on controlling non-agricultural NH₃ emissions in the future.