GEM/POPs: a global 3-D dynamic model for semi-volatile persistent organic pollutants – Part 2: Global transports and budgets of PCBs
1Air Quality Research Division, Science & Technology Branch, Environment Canada, 4905 Dufferin Street, Toronto, Ontario M3H 5T4, Canada
2Department of Chemical Engineering and Applied Chemistry, University of Toronto 200 College Street, Toronto, Ontario, Canada, M5S 3E5, Canada
3Department 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 peak transport flux below 8 km and 14 km for gaseous and particulate PCB28, 4 km and 6 km for gaseous and particulate PCB180. The inter-continental transports of PCBs in the Northern Hemisphere (NH) are dominated in the zonal direction with their route changes seasonally regulated by the variation of westerly jet. The transport pathways from Europe and North Atlantic to the Arctic contributed the most PCBs over there. 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 export 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 and 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. It is found that lighter PCBs have more long range transport potentials than their heavier counter-parts in the atmosphere.