Atmospheric amines in urban Beijing: measurements, characteristics and potential sources

Amines are important alkaline gases in the atmosphere besides ammonia, profoundly influencing air quality, climate and human health through complex physicochemical processes. They facilitate new particle formation through acid-base nucleation process, with the resulting particles further growing into cloud condensation nuclei or contributing to secondary particulate pollution. They also participate in atmospheric oxidation process, yielding toxic gaseous pollutants such as aldehydes, nitramines, and nitrosamines. An increase in atmospheric amine abundance could lead to adverse effects to the environment. Vocus Proton-Transfer-Reaction Mass Spectrometry (Vocus-PTR) is an effective technique in volatile organic compounds (VOCs) detection. In this study, we optimized the condition of focusing ion-molecule reactor (FIMR) of Vocus-PTR to measure a wider variety of amines with lower concentrations, achieving good performance in the detection of both atmospheric amines and VOCs. Using the optimized Vocus-PTR, we conducted field measurement at a typical urban site in Beijing, China. C2-6-alkylamines, C1-6-amides and several emerging amines were identified and quantified. Their concentrations, atmospheric variations and potential sources are further investigated.