Air and water samples were collected from Taihu Lake, East China through 2004 and analyzed for 33 congeners of polybrominated diphenyl ether (PBDE) and other seven brominated and chlorinated flame retardants. The annual concentration of total atmospheric PBDEs was 220 pg m(-3); BDE-209 was most abundant (average 41% of total PBDEs), followed by BDE-47 (17%) and BDE-28 (15%). The relative abundance of tetra- and tri-BDE congeners (including BDE-47, -28, -49, -66, and -17) instead of BDE-99 indicated that a specific penta-BDE formulation might be produced and/or consumed in this region. The source was confirmed by the analysis of air-water gas exchange, which was nearly at equilibrium in spring and summer but displayed strong volatilization flux in autumn and winter, especially for BDE-28, indicating the potential wastewater discharge of PBDEs into the lake. In addition to PBDEs, hexabromobenzene, 1,2-bis(2,4,6-tribromophenoxy)ethane, decabromodiphenylethane, and Dechlorane Plus were detected in air samples, with an annual mean concentration of 23 pg m-3 for decabromodiphenylethane, and <4 pg m(-3) for the others. (C) 2010 Elsevier Ltd. All rights reserved.
Measurements made at a rural site in central Ontario during May-June 2007 are used to investigate the composition of organic aerosol (OA) downwind of an urban region. Observations of aerosol organic carbon and oxygen containing fragments from a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) are combined with toluene to benzene ratios to estimate the relative importance of secondary organic aerosol (SOA) and primary organic aerosol (POA) to the total OA at the site during periods of significant urban influence. We estimate that SOA formed within 1-2 days of the anthropogenic source regions was 40-50% of the measured OA and that POA was 5-16% of the OA. The remaining 35-45% of the OA is assumed to have been present in the aerosol upwind of the source regions prior to entering the study domain as defined by trajectories and estimates of the potential photochemical aging time. The apportionment results were also compared to that of positive matrix factorization analysis. In addition, the measurements of the molar oxygen to carbon ratio (O/C) in the OA demonstrates that SOA becomes progressively more oxygenated with increasing photochemical age and at low total OA mass.