GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs P. Huang1, S. L. Gong1,2, T. L. Zhao2, L. Neary3, and L. A. Barrie4 1Air Quality Research Division, Science & Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada 2Dept. of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, Canada, M5S 3E5, Canada 3Dept. of Earth and Space Science and Engineering, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada 4Atmospheric Research and Environment Program, World Meteorological Organization, 7 bis, avenue de la Paix, BP2300, 1211 Geneva 2, Switzerland
Abstract. Global transports and budgets of three PCBs were investigated with a 3-D
dynamic model for semi-volatile persistent organic pollutants – GEM/POPs.
Dominant pathways were identified for PCB transports in the atmosphere with
a transport flux peaking below 8 km for gaseous and 14 km for particulate
PCB28, and peaking below 4 km for gaseous and 6 km for particulate PCB180.
The inter-continental transports of PCBs in the Northern Hemisphere (NH) are
dominated in the zonal direction with their route changes regulated
seasonally by the variation of westerly jet. The transport pathways from
Europe and North Atlantic contributed the most PCBs to the Arctic.
Inter-hemispheric transports of PCBs originated from the regions of Europe,
Asia and North America in three different flow-paths, accompanying with
easterly jet, Asian monsoon winds and trade winds. PCBs from the Southern
Hemisphere (SH) could also be exported into the NH. According to the PCB
emissions of year 2000, Europe, North America and Asia are the three largest
sources of the three PCBs, contributing to the global background
concentrations in the atmosphere, soil and water. Globally, PCB28 in soil
and water has become a comparable source to the anthropogenic emissions
while heavier PCBs such as PCB153 and 180 are still transporting into soil
and water. For all three congeners, particulate PCBs are concentrated in the
higher levels than gaseous PCBs. More than half of the particulate PCB28
could reach up to the stratosphere, while most of the heavier counter-parts
(PCB153 and PCB180) are stored in the troposphere including boundary layer
with more than 99% gaseous PCB180 below 6 km.
Citation: Huang, P., Gong, S. L., Zhao, T. L., Neary, L., and Barrie, L. A.: GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs, Atmos. Chem. Phys., 7, 4015-4025, doi:10.5194/acp-7-4015-2007, 2007.