NONMETHANE HYDROCARBONS AND CO DURING PACIFIC-93

Measurements of hydrocarbons and CO that were made during the summer o f 1993 as part of the PACIFIC 93 field study in the Lower Fraser Valle y, B.C., Canada are summarized. Good comparison between diverse data s ets is observed. It appears that on basis of percent carbon (by weight ) alkanes (excluding ethane) represent about 55%, alkenes 10%, aromati cs (excluding benzene) 20%, and the biogenic hydrocarbon isoprene 3% o f the total mass. Classification schemes that incorporate the differen t reactivity of the compounds suggest much less importance of the alka nes in favor of the alkenes and aromatics. About 10% of ozone producti on seems to be due to isoprene chemistry alone. Ozone is shown to incr ease during the day most likely due to photochemistry involving these hydrocarbons. Using hydrocarbon data from a location downwind of the c ity of Vancouver, and maximum ozone reactivity (MOR) factors derived b y Carter (1991, EPA Report, 84pp.) it is estimated that the O-3 produc tion rate in the first week of August 1993 might have been as high as 8 ppbv h(-1). (C) 1997 Elsevier Science Ltd.