Source contribution of PCBs and OC/EC at a background site in the Yangtze River Estuary: insight from inter-comparison by Positive Matrix Factorization (PMF)

Abstract

AbstractBackground air samples, including gas-phase components and suspended particulates, were collected over one year (2013-2014) for an investigation of polychlorinated biphenyls (PCBs) and OC/EC in the Yangtze River Estuary. PCB concentrations exhibited great seasonal variability and ranged between 43 and 720 pg·m−3. They mainly were associated with the gas phase, and levels peaked in the summer time at 327 ± 177 pg·m−3. By contrast, concentrations of particulate PCBs and OC/EC were higher in the cold seasons, which was due to high-temperature combustion emission and frequent haze events. According to the results of a positive matrix factorization, the combustion and non-combustion sources of PCBs accounted for 30% and 70% of total PCBs, respectively. Meanwhile, SOC/OC value was 54.7% ± 20.1%, which suggests gas-to-particle conversion process plays a significant role in contributing to atmospheric particles. To this end, the influence of OC/EC on both combustion and non-combustion PCBs in the long-range atmospheric transport deserves further research. Graphical Abstract