title: Source apportionment using radiocarbon and organic tracers for PM2.5 carbonaceous aerosols in Guangzhou, South China: contrasting local- and regional-scale haze events.
abstract: We conducted a source apportionment and investigated the atmospheric behavior of carbonaceous aerosols during hazy and normal days using radiocarbon ((14)C) and biomass burning/secondary organic aerosol (SOA) tracers during winter in Guangzhou, China. Haze episodes were formed either abruptly by local emissions or through the accumulation of particles transported from other areas. The average contributions of fossil carbon to elemental carbon (EC), water-insoluble organic carbon, and water-soluble organic carbon were 71 ± 10%, 40 ± 6% and 33 ± 3%, respectively. High contributions of fossil carbon to EC (80-90%) were observed for haze samples that were substantially impacted by local emissions, as were the highest (lowest) ratios for NO3(-)/SO4(2-) (OC/EC), which indicates that these particles mainly came from local vehicle exhaust. Low contributions of fossil carbon to EC (60-70%) were found for haze particles impacted by regional transport. Secondary organic carbon (SOC) calculated using SOA tracers accounts for only ∼ 20% of the SOC estimated by (14)C, which is probably because some important volatile organic carbons are not taken into account in the SOA tracer calculation method and because of the large discrepancy in ambient conditions between the atmosphere and smog chambers. A total of 33 ± 11% of the SOC was of fossil origin, a portion of which could be influenced by humidity.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences , Guangzhou, 510640, People's Republic of China.
authors.forename: Junwen
authors.initials: J
authors.lastname: Liu
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Yanlin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Ding
authors.forename: Chengde
authors.initials: C
authors.lastname: Shen
authors.forename: Kaijun
authors.initials: K
authors.lastname: Shen
authors.forename: Quanfu
authors.initials: Q
authors.lastname: He
authors.forename: Xiang
authors.initials: X
authors.lastname: Ding
authors.forename: Xinming
authors.initials: X
authors.lastname: Wang
authors.forename: Duohong
authors.initials: D
authors.lastname: Chen
authors.forename: Sönke
authors.initials: S
authors.lastname: Szidat
authors.forename: Gan
authors.initials: G
authors.lastname: Zhang
mesh_terms: D000336:Aerosols / Q000032:analysis* / Q000737:chemistry; D000393:Air Pollutants / Q000032:analysis; D018533:Biomass; D002244:Carbon / Q000032:analysis / Q000737:chemistry; D002250:Carbon Radioisotopes; D002681:China; D004784:Environmental Monitoring / Q000379:methods*; D006813:Humidity; D009566:Nitrates / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis; D012621:Seasons; D012995:Solubility; D013431:Sulfates / Q000032:analysis; D001335:Vehicle Emissions; D014867:Water
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D002250:Carbon Radioisotopes; D009566:Nitrates; D052638:Particulate Matter; D013431:Sulfates; D001335:Vehicle Emissions; D014867:Water; D002244:Carbon