关键词：大气；碳氧化合物；空气污染
摘 要：This study is composed of the following sections: (1) collection and measurement of ambient fine particles during the intensive field campaign, (2) factor analysis for source apportionment, (3) identifying particle clusters using cluster analysis, and (4) studying formation mechanisms of the SOA components. We measured chemical composition of submicron particle mass (PM1) and sub 2.5 micron particle mass (PM2.5) using a set of complementary, ensemble, and single particle analysis techniques, including Fourier transform infrared (FTIR) spectroscopy, Aerosol Mass Spectrometry (AMS), and scanning transmission X-ray microscopy with near edge absorption fine structure (STXM-NEXAFS). Positive matrix factorization (PMF) was used to extract major components that contributed to the organic mass. Cluster analysis applied to the ensemble infrared spectra, the single-particle mass, and NEXAFS spectra separated particles into several groups, each of which has characteristics of distinct sources or atmospheric processes. By showing the consistency of particle source types (from factor analysis) and clusters, we indicate that SOA accounts for a major fraction of fine particle mass. Based on the composition and diurnal cycle of the SOA components and their relationships with potential atmospheric oxidants, formation mechanisms of the SOA components were estimated.