MEASUREMENTS OF PAN, ALKYL NITRATES, OZONE, AND HYDROCARBONS DURING SPRING IN INTERIOR ALASKA

Measurements of the atmospheric mixing ratios of ozone, peroxyacetylni ltrate (PAN), hydrocarbons, and alkyl nitrates were made in a boreal f orest ecosystem in the interior of Alaska from March 15 to May 14, 199 3. During this period the mixing ratios of PAN, alkyl nitrates, and no nmethane hydrocarbons (NMHCs) generally decreased due to the influence of both meteorology and OH removal. Mean mixing ratios of ozone, PAN, C-2-C-6 alkyl nitrates, and total C-2-C-5 NMHC during southerly flow periods were 24.4 parts per billion (ppbv), 132.1 parts per trillion ( pptv), 34 pptv, and 8.2 ppbCv, respectively. During a short period of northerly flow, mixing ratios of PAN and total NMHC were approxinately 2 times the southerly flow mixing ratios. PAN is correlated with ozon e, and alkyl nitrates are correlated with alkanes. PAN and ozone mixin g ratios exhibit similar diurnal variations on a number of days with a n early morning minimum and afternoon maximum. This is likely due to a diurnal cycle in the boundary layer-free troposphere exchange and los s processes in the boundary layer for both O-3 and PAN. Higher molecul ar weight (mw) hydrocarbons and alkyl nitrates are observed to decreas e more quickly than the lower mw hydrocarbons consistent with removal by OH as the primary loss process.