10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
The Birth of Haze: Molecular Understanding of New Particle Formation in Beijing
YING ZHOU, Chao Yan, Juha Kangasluoma, Yonghong Wang, Federico Bianchi, Tommy Chan, Biwu Chu, Lubna Dada, Kaspar Rudolf Dällenbach, Yueyun Fu, Xucheng He, Liine Heikkinen, Yiliang Liu, Yiqun Lu, Qingxin Ma, Pekka Rantala, Gan Yang, Rujin Yin, Joni Kujansuu, Tuukka Petäjä, Yongchun Liu, Lin Wang, Jingkun Jiang, Markku Kulmala, Beijing University of Chemical Technology
Abstract Number: 657 Working Group: Aerosol Chemistry
Abstract New Particle Formation (NPF) is an important source of atmospheric aerosol particles in the atmosphere that have known impacts on health, visibility and climate. Additionally, recent studies discuss the potential role of newly born particles in haze formation. In the last decade, NPF has been investigated both in ambient environments, such as in boreal forest or mountain slopes as well as in atmospheric simulation chambers, especially in the CLOUD experiment at CERN. Despite the large number of studies, only few NPF observations from highly polluted urban environments have been reported and the detailed understanding of such cases is still insufficient.
In order to better understand the complexity of air pollution, and especially the formation of haze events in Chinese megacities, we are conducting comprehensive long-term measurements in downtown Beijing. The newly constructed measurement station is equipped with state-of-the-art instruments for aerosol research focusing on new particle formation. The physical properties of aerosol particles are measured with a Particle Sizer Magnifier (PSM), a Neutral cluster and Air Ion Spectrometer (NAIS) and a scanning mobility particle sizer with diethylene glycol as the working fluid (DEG-SMPS). The chemical characterization of aerosol particles as well as the nucleating clusters is performed with chemical ionization mass spectrometers (CIMS) using different types of chemical ionization techniques (such as NO3- and I-), a regular atmospheric pressure interface time-of-flight mass spectrometer (APi-TOF) a filter inlet for gases and aerosols mounted in front of a CIMS (FIGAERO-CIMS) , and a time of flight aerosol chemical speciation monitor (TOF-ACSM).
During the measurement period in urban Beijing, we observed a frequent occurrence of NPF events. We classified these events into three groups according to the air pollution index: clean days, moderately polluted days, and highly polluted days, respectively. Formation rate, growth rate and condensation sink were calculated for each of the groups. Additionally, the behavior of gas phase sulfuric acid and highly oxygenated molecules were analyzed and compared among the different pollution categories.
Our study provided new and comprehensive insights into aerosol formation, growth and thereafter haze formation in a molecular level in urban Beijing that is needed for more efficient emission control strategies in the highly developing North China Plain.