[1] Univ Montana, Dept Chem, Missoula, MT 59812 USA
[2] Max Planck Inst Chem, Atmospher Chem Dept, D-55128 Mainz, Germany
[3] Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA
[4] US Forest Serv, Fire Sci Lab, USDA, Missoula, MT 59807 USA
[5] Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA