MEASUREMENT OF PCCS IN AIR IN SOUTHERN ONTARIO

In 1988 and 1989, a study of the annual cycle of PCBs, organohalogen P esticides and herbicides was undertaken at Egbert, Ontario, Canada. Th is paper examines, in additional detail, the annual behaviour of the p olychlorinated bornanes or camphenes (called PCCs here) in southern on tario in air. The results show that the annual cycle of PCCs peaks in the summer months, indicating volatilization of PCCs from the earth's surface. A best fit linear regression of the logarithm of the air conc entration gives an inverse temperature slope which is -4780, very clos e to the vapour pressure slope. This result is used to rederive the an nual cycle using only the air temperature and a much closer representa tion to the air concentration values is found than was presented in an earlier work. The deviations of the air concentrations from these pre dictions are analysed in terms of air trajectory analysis and the five highest concentration deviations are due to air masses arriving in on tario from the southern U.S.