Determination of C2 to C12 ambient air hydrocarbons in 39 US cities from 1984 through 1986

Abstract

Currently more than 60 urban areas are not in compliance with the National Ambient Air Quality Standard (NAAQS) for ozone. The use of photochemical models will be necessary to forecast the nonmethane organic compound (NMOC) reductions needed to attain the NAAQS. These models require knowledge of the individual organic species in ambient air. To this end, speciated hydrocarbons were determined in over 800 ambient air samples obtained from 39 U.S. cities during 1984, 1985, and 1986. Whole-air samples were collected in electropolished, stainless steel spheres on weekdays from 6 to 9 A.M. during June through September each year. Two gas-chromatographic (GC) procedures with cryogenic sample preconcentration were employed to separate and measure C2 to C12 hydrocarbon species. Menu-driven software was developed to transfer GC data to a personal computer. The 48 compounds seen in highest concentration consisted of 25 paraffins, 15 aromatics, 7 olefins, and acetylene. Sample concentrations of the 64 most abundant species are reported.