title: Characteristics of dimethylaminium and trimethylaminium in atmospheric particles ranging from supermicron to nanometer sizes over eutrophic marginal seas of China and oligotrophic open oceans.
abstract: In this study, we characterized dimethylaminium (DMA+) and trimethylaminium (TMA+) in size-segregated atmospheric particles during three cruise campaigns in the marginal seas of China and one cruise campaign mainly in the northwest Pacific Ocean (NWPO). An 14-stage nano-MOUDI sampler was utilized for sampling atmospheric particles ranging from 18μm to 0.010μm. Among the four cruise campaigns, the highest concentrations of DMA+and TMA+in PM10were observed over the South Yellow Sea (SYS) in August 2015, i.e., 0.76±0.12nmolm-3for DMA+(average value±standard deviation) and 0.93±0.13nmolm-3for TMA+. The lowest values were observed over the NWPO in April 2015, i.e., 0.28±0.16nmolm-3for DMA+and 0.22±0.12nmolm-3for TMA+. In general, size distributions of the two ions exhibited a bi-modal pattern, i.e., one mode at 0.01-0.1μm and the other at 0.1-1.8μm. The two ions' mode at 0.01-0.1μm was firstly observed. The mode was largely enhanced in samples collected over the SYS in August 2015, leading to high mole ratios of (DMA++TMA+)/NH4+in PM0.1(0.4±0.8, median value±standard deviation) and the ions' concentrations in PM0.1accounting for ~10% and ~40% of their corresponding concentrations in PM10. This implied that (DMA++TMA+) likely played an important role in neutralizing acidic species in the smaller particles. Using SO42-, NO3-and NH4+as references, we confirm that the elevated concentrations of DMA+and TMA+in the 0.01-0.1μm size range were probably real signals rather than sampling artifacts.
authors: Key Lab of Marine Environmental Science and Ecology (MoE), Ocean University of China, Qingdao 266100, China.
authors: Peiran
authors: P
authors: Yu
authors: Key Laboratory of Sustainable Utilization of Marine Fisheries Resources (MoA), Yellow Sea Fisheries Research Institute, Chinese Academy of Fisheries Sciences, Qingdao 266071, China. Electronic address: huqj@ysfri.ac.cn.
authors: Qingjing
authors: Q
authors: Hu
authors: National Marine Environmental Forecasting Center, Beijing 100081, China.
authors: Kai
authors: K
authors: Li
authors: Key Lab of Marine Environmental Science and Ecology (MoE), Ocean University of China, Qingdao 266100, China.
authors: Yujiao
authors: Y
authors: Zhu
authors: Key Lab of Marine Environmental Science and Ecology (MoE), Ocean University of China, Qingdao 266100, China.
authors: Xiaohuan
authors: X
authors: Liu
authors: Key Lab of Marine Environmental Science and Ecology (MoE), Ocean University of China, Qingdao 266100, China; Qingdao Collaborative Center of Marine Science and Technology, Qingdao 266100, China.
authors: Huiwang
authors: H
authors: Gao
authors: Key Lab of Marine Environmental Science and Ecology (MoE), Ocean University of China, Qingdao 266100, China; Qingdao Collaborative Center of Marine Science and Technology, Qingdao 266100, China. Electronic address: xhyao@ouc.edu.cn.
authors: Xiaohong
authors: X
authors: Yao
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004123:Dimethylamines / Q000737:chemistry; D004784:Environmental Monitoring; D008744:Methylamines / Q000737:chemistry; D010140:Pacific Ocean; D052638:Particulate Matter / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D004123:Dimethylamines; D008744:Methylamines; D052638:Particulate Matter; C034516:dimethylamine; C023336:trimethylamine
keywords: Amines; Marine aerosol; NH(4)(+); Size distribution; The Pacific Ocean