Diurnal Variations of Individual Organic Compound Constituents of Ultrafine and Accumulation Mode Particulate Matter in the Los Angeles Basin
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- 作者：Philip M Fine ; Bhabesh Chakrabarti ; Meg Krudysz ; James J. Schauer ; and Constantinos Sioutas
- 刊名：Environmental Science & Technology
- 出版年：2004
- 出版时间：March 1, 2004
- 年：2004
- 卷：38
- 期：5
- 页码：1296 - 1304
- 全文大小：219K
- 年卷期：v.38,no.5(March 1, 2004)
- ISSN：1520-5851
文摘
Individual organic compounds can be used as tracers forprimary sources of ambient particulate matter (PM) inchemical mass balance receptor models. Previous workhas examined PM2.5 only and usually over long samplingperiods encompassing entire days or longer. In this study,a high-flow-rate, low-pressure-drop ultrafine particleseparator was deployed to collect sufficient mass fororganic speciation of ultrafine and accumulation modeaerosol on a diurnal basis. Particles between 0.18 and 2.5
m in diameter were collected on a quartz-fiber impactionsubstrate, and ultrafine particles below 0.18 m were collecteddownstream on a high-volume filter. Four daily timeperiod samples (morning, midday, evening, and overnight)were sampled over five weekdays to form a weeklyaverage composite for each diurnal period. Sampling wasconducted at two sites over two seasons; summer(August) and winter (January) samples were collected atboth an urban site near downtown Los Angeles (Universityof Southern California) and a downwind, inland site inRiverside, CA. Hopanes, used as organic markers for vehicularemissions, were found to exist primarily in the ultrafinemode. Levoglucosan, an indicator of wood combustion, wasquantified in both size ranges, but more was present inthe accumulation mode particles. An indicator ofphotochemical secondary organic aerosol formation, 1,2-benzenedicarboxylic acid, was found primarily in theaccumulation mode and varied with site, season, and timeof day as one would expect for a photochemical product.The atmospheric variations of particulate cholesteroland other organic acids were also considered. By examiningthe diurnal variation, size-fractionation, and intercorrelationsof individual organic compounds, the sources andatmospheric fate of these tracers can be better understoodand their utility as molecular markers can be assessed.
m in diameter were collected on a quartz-fiber impactionsubstrate, and ultrafine particles below 0.18 m were collecteddownstream on a high-volume filter. Four daily timeperiod samples (morning, midday, evening, and overnight)were sampled over five weekdays to form a weeklyaverage composite for each diurnal period. Sampling wasconducted at two sites over two seasons; summer(August) and winter (January) samples were collected atboth an urban site near downtown Los Angeles (Universityof Southern California) and a downwind, inland site inRiverside, CA. Hopanes, used as organic markers for vehicularemissions, were found to exist primarily in the ultrafinemode. Levoglucosan, an indicator of wood combustion, wasquantified in both size ranges, but more was present inthe accumulation mode particles. An indicator ofphotochemical secondary organic aerosol formation, 1,2-benzenedicarboxylic acid, was found primarily in theaccumulation mode and varied with site, season, and timeof day as one would expect for a photochemical product.The atmospheric variations of particulate cholesteroland other organic acids were also considered. By examiningthe diurnal variation, size-fractionation, and intercorrelationsof individual organic compounds, the sources andatmospheric fate of these tracers can be better understoodand their utility as molecular markers can be assessed.