title: Temporal variations of black carbon during haze and non-haze days in Beijing.
abstract: Black carbon (BC) aerosol has been identified as one of key factors responsible for air quality in Beijing. BC emissions abatement could help slow regional climate change while providing benefits for public health. In order to quantify its variations and contribution to air pollution, we systematically studied real-time measurements of equivalent black carbon (eBC) in PM2.5 aerosols at an urban site in Beijing from 2010 to 2014. Equivalent black carbon (eBC) is used instead of black carbon (BC) for data derived from Aethalometer-31 measurement. Equivalent BC concentrations showed significant temporal variations with seasonal mean concentration varying between 2.13 and 5.97 μg m(-3). The highest concentrations of eBC were found during autumn and winter, and the lowest concentrations occurred in spring. We assessed the temporal variations of eBC concentration during haze days versus non-haze days and found significantly lower eBC fractions in PM2.5 on haze days compared to those on non-haze days. Finally, we observed a clear inverse relationship between eBC and wind speed. Our results show that wind disperses PM2.5 more efficiently than eBC; so, secondary aerosols are not formed to the same degree as primary aerosols over the same transport distance during windy conditions.
authors.affiliation: College of Biology and the Environment, Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Nanjing Forestry University, Nanjing, China.|Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Qingyang
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Biology and the Environment, Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Nanjing Forestry University, Nanjing, China.
authors.forename: Tangming
authors.initials: T
authors.lastname: Ma
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Olson
authors.affiliation: Beijing Center for Physical and Chemical Analysis, Beijing, China.
authors.forename: Yanju
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Beijing Center for Physical and Chemical Analysis, Beijing, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.affiliation: College of Biology and the Environment, Collaborative Innovation Center of Sustainable Forestry in Southern China of Jiangsu Province, Nanjing Forestry University, Nanjing, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Environmental Chemistry and Technology Program, University of Wisconsin-Madison, Madison, WI, USA.|Wisconsin State Laboratory of Hygiene, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Schauer
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000032:analysis*; D000068476:Beijing; D002244:Carbon / Q000032:analysis*; D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D010316:Particle Size; D012621:Seasons; D053260:Soot / Q000032:analysis*; D014919:Wind
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D053260:Soot; D002244:Carbon