title: [Pollution Characteristics and Light Extinction Effects of Water-soluble Ions in PM2.5 During Winter Hazy Days at North Suburban Nanjing].
abstract: To investigate the characteristics of water-soluble ions in PM2.5 and their contribution to light extinction in haze days, on-line monitoring of PM2.5. was conducted at North Suburban Nanjing from 25 January through 3 February, 2013. Water-soluble components were collected with a particle-into-liquid sampler (PILS), and analyzed by ion chromatography (IC) for the contents of SO4(2-), NO3-, NH4+, Cl-, Na+, K+, Mg2+ and Ca2+ Simultaneously particle size distributions were measured using scanning mobility particle sizer (SMPS) and Aerodynamic Particle Sizer (APS). The absorption and scattering coefficients were measured by three-wavelength photoacoustic soot spectrometer (PASS-3). Trace gases (SO2, NO2 etc.) were also monitored. The results showed that the average concentrations of total water-soluble ions were 70.3 and 22.9 microg x m(-3) in haze and normal days, respectively. Secondary hygroscopic components including SO4(2-), NO3- and NH4+ were the major ionic pollutants. Hazy days favored the conversion of SO2 and NOx, to SO4(2-) and NO3-, respectively, and in particular the oxidation of NOx. Using multiple linear regression statistical method, the empirical relationship between the dry aerosol extinction coefficient and the chemical composition was established. NH4NO3 was found to be the largest contributor to aerosol extinction in winter in Nanjing, followed by (NH4)2SO4, OC and EC. In two heavy pollution events, the increase of ion concentrations was influenced by the increase of primary emissions and secondary transformation.
authors.forename: Yao-yao
authors.initials: YY
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Ma
authors.forename: Jun
authors.initials: J
authors.lastname: Zheng
authors.forename: Fen-ping
authors.initials: FP
authors.lastname: Cui
authors.forename: Li
authors.initials: L
authors.lastname: Wang
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D002681:China; D002947:Cities; D004784:Environmental Monitoring; D005740:Gases; D007477:Ions; D008027:Light; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D012995:Solubility; D014867:Water
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D005740:Gases; D007477:Ions; D052638:Particulate Matter; D014867:Water