1. Meteorological Service of Canada, Atmospheric Toxic Processes
Section, Environment Canada, 100 Boulevard Alexis Nihon,
Suite 300, Ville St. Laurent, Québec, Canada, H4M 2N8,
INRS-EAU, Université du Québec, 2800 Rue Einstein,
C.P. 7500, Sainte-Foy, QC, G1V 4C7, Canada, and
Department of Biology, University of Ottawa,
P.O. Box 450 Station A, Ottawa, K1N 6N5, Canada