title: Characterization of mineral particles in winter fog of Beijing analyzed by TEM and SEM.
abstract: Aerosol samples were collected during winter fog and nonfog episodes in Beijing. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were applied to study morphologies, sizes, and compositions of aerosol particles. TEM observation indicates that most mineral particles collected in fog episode are scavenged in fog droplets. Number-size distributions of mineral particles collected in fog and nonfog episodes show two main peaks at the ranges of 0.1-0.3 and 1-2.5 microm, respectively. Based on their major compositions, mineral particles mainly include Si-rich, Ca-rich, and S-rich. Average S/Ca ratio of mineral particles collected in fog episode is 6.11, being eight times higher than that in nonfog episodes. Development mechanism of individual mineral particles in fog droplets is proposed. It is suggested that mineral particles with abundant alkaline components (e.g., "Ca-rich" particles) occurred in air should alleviate acidic degree of fog and contribute to complexity of fog droplets in Beijing.
authors.affiliation: The State Key Laboratory of Coal Resources and Safe Mining and the Department of Resources and Earth Science, China University of Mining and Technology in Beijing, Beijing, 100083, China. liweijun.atmos@gmail.com
authors.forename: Weijun
authors.initials: W
authors.lastname: Li
authors.forename: Longyi
authors.initials: L
authors.lastname: Shao
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring; D008855:Microscopy, Electron, Scanning / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D010316:Particle Size; D014887:Weather
chemical_list: D000393:Air Pollutants