Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from 15N-Stable Isotope in Size-Resolved Aerosol Ammonium

• DOI: 10.1021/acs.est.6b00634
• Publication Date: 2016-06-30T20:58:23Z
• Authors: Yuepeng Pan; Shili Tian; Dongwei Liu; Yunting Fang; Xiaying Zhu; Qiang Zhang; Bo Zheng; Greg Michalski; Yuesi Wang
• Keywords: Haze; Atmospheric chemistry

The reduction of ammonia (NH3) emissions is urgently needed due to its role in aerosol nucleation and growth causing haze formation during conversion into ammonium (NH4+). However, the relative contributions individual NH3 sources are unclear, debate remains over whether agricultural dominate atmospheric urban areas. Based on chemical isotopic measurements size-resolved aerosols Beijing, China, we find that natural abundance 15N (expressed using δ15N values) NH4+ fine particles varies with development episodes, ranging from −37.1‰ −21.7‰ clean/dusty days (relative humidity: ∼ 40%), −13.1‰ +5.8‰ hazy 70–90%). After accounting for isotope exchange between gas NH4+, value initial found be −14.5‰ −1.6‰, which indicates fossil fuel-based emissions. These contribute 90% total Beijing. This work demonstrates analysis values a promising new tool partitioning sources, providing policy makers insights secondary regulation environments.