MEASUREMENTS OF HYDROCARBONS, OXYGENATED HYDROCARBONS, CARBON-MONOXIDE, AND NITROGEN-OXIDES IN AN URBAN BASIN IN COLORADO - IMPLICATIONS FOR EMISSION INVENTORIES

Concentrations of a wide variety of volatile organic compounds (VOCs) in the C-3 to C-10 range, CO, NOy (total reactive oxidized nitrogen), SO2, and meteorological parameters were measured concurrently at a sit e on the western perimeter of Boulder, Colorado, during February 1991. The measurement site, located some 150 m above the Boulder urban basi n, receives air masses typifying averaged local sources. The highest h ydrocarbon concentrations observed showed little effects of photochemi cal loss processes and reflect the pattern of the local emission sourc es. The observed ratios of CO and the VOCs to NOy are compared to thos e predicted by the 1985 National Acid Precipitation Assessment Program (NAPAP) inventory. These comparisons indicate (1) good agreement for CO/NOY, (2) significant overpredictions by the NAPAP inventory for man y of the hydrocarbon to NOY ratios,(3) much more benzene from mobile s ources(and less from area sources) than predicted by the NAPAP invento ry, and (4) large underpredictions of the light alcohols and carbonyls by the NAPAP inventory. These first two results are in marked contras t to the conclusions of the recent tunnel study reported by Ingalls in 1989. Source profile reconciliation implies substantial input from bo th a local propane source and gasoline headspace venting.