[1] Environm Canada, Atmospher Sci & Technol Directorate, Air Qual Res Div, Toronto, ON M3H 5T4, Canada
[2] SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12203 USA
[3] SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12203 USA
[4] Envair Aerochem, Placitas, NM 87043 USA
[5] MIT, La Jolla, CA 92037 USA
[6] Molina Ctr Energy & Environm, La Jolla, CA 92037 USA
[7] Columbia Res & Educ Associates, Columbia, WA 99301 USA
[8] US EPA, Durham, NC 27711 USA