MODELING THE EFFECTS OF A CLIMATE CHANGE SCENARIO ON THE DISTRIBUTION OF ORGANIC POLLUTANTS IN THE GLOBAL ATMOSPHERE

摘要

We have applied a global multimedia fate model to evaluate changes in the atmospheric distribution of two polychlorinated biphenyls, PCB 28 and PCB 153, under the influence of climate change. We defined a climate scenario representing the last twenty years of the 20th century ("20CE scenario") and a scenario representing the global climate under the assumption of strong future greenhouse gas emissions ("A2 scenario"). These two climate scenarios are defined by four groups of environmental factors: 1) temperature in the atmosphere, 2) wind speeds and directions, 3) oceanic current velocities and directions, and 4) precipitation rate and geographical pattern. As a fifth factor in our scenarios, we consider the effect of temperature on primary volatilization emissions of PCBs. Comparison of model results for the 20CE scenario against long-term monitoring data of concentrations of PCBs in air shows satisfactory agreement between modeled and measured PCBs concentrations. Temperature and wind differences between the two scenarios are the dominant factors determining the difference in atmospheric distribution of PCB under the A2 scenario. This study indicates that, in a future impacted by climate change, we can expect increased volatilization emissions and increased mobility of persistent organic pollutants with properties similar to the PCBs.