摘要:

Gaseous dicarboxylic acids (diacids) are suggested to participate in atmospheric new particle formation via bonding with sulfuric acid (SA), ammonia (NH3), amines, and other molecules. However, there is a lack of observational evidence for the involvement of diacids in particle nucleation. Comprehensive measurements were conducted at a rural site of the North China Plain in winter, and unexpectedly high nucleation rates (JOBS, 30.5-839.7 cm-3 s-1) were observed under low SA levels (0.7 × 106 to 4.4 × 106 cm-3). Neither SA-NH3 nor SA-dimethylamine (DMA) mechanisms could fully explain the JOBS. Gaseous diacid monomers and dimers and diacid-SA-DMA clusters were identified in this study. The JOBS values were enhanced by a factor of 5 to 10 as the signal intensities of diacids increased 4-fold. Products of diacid signals and SA concentrations showed a positive correlation with the JOBS (Pearson's correlation coefficient = 0.72). Experimental evidence was found that succinic acid competes with the second SA molecule for addition to the SA·DMA cluster. The concentrations of diacids were estimated to be 1-3 orders of magnitude higher than those of SA. We propose that diacids could actively participate in particle nucleation and may dominate the initial steps under high [diacids]/[SA] ratios. Copyright © 2020 American Chemical Society.

附注:

Export Date: 20 August 2020通讯地址: Hu, M.; State Key Joint Laboratory of Environmental Simulation and Pollution Control, Department of Environmental Science, Peking University, Beijing Innovation Center for Engineering Sciences and Advanced Technology, Peking UniversityChina; 电子邮件: minhu@pku.edu.cn基金资助详情: DQGG0103基金资助详情: National Basic Research Program of China (973 Program), 2016YFC0202000基金资助详情: 2019-01433基金资助详情: National Natural Science Foundation of China, NSFC, 91844301, 41730106, 41675126基金资助详情: National Natural Science Foundation of China, NSFC基金资助文本 1: This study was supported by the National Natural Science Foundation of China (NSFC) research projects (91844301, 41675126, and 41730106), the National Key Research and Development Program of China (2016YFC0202000: Task 3), the National Research Program for Key Issues in Air Pollution Control (DQGG0103), and the Swedish Research Council for Sustainable Development (Formas; project 2019-01433). We thank the Pingyuan Meteorological Bureau for providing us with access to the Pingyuan rural site for measurements. We acknowledge Michael Boy and Pontus Roldin for constructive comments that improved the manuscript.