Gas/Particle Partitioning of 2-Methyltetrols and Levoglucosan at an Urban Site in Denver

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• 作者：Mingjie Xie ; Michael P. Hannigan ; Kelley C. Barsanti
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：March 4, 2014
• 年：2014
• 卷：48
• 期：5
• 页码：2835-2842
• 全文大小：337K
• 年卷期：v.48,no.5(March 4, 2014)
• ISSN：1520-5851

文摘

In this study, a medium volume sampler incorporating quartz fiber filters (QFFs) and a polyurethane foam (PUF)/XAD/PUF sandwich (PXP) was used to collect 2-methyltetrols (isoprene tracer) and levoglucosan (biomass burning tracer) in gaseous and particle (PM_2.5) phases. The measured gas/particle (G/P) partitioning coefficients (K_p,OM^m) of 2-methyltetrols and levoglucosan were calculated and compared to their predicted G/P partitioning coefficients (K_p,OM^t) based on an absorptive partitioning theory. The breakthrough experiments showed that gas-phase 2-methyltetrols and levoglucosan could be collected using the PXP or PUF adsorbent alone, with low breakthrough; however, the recoveries of levoglucosan in PXP samples were lower than 70% (average of 51.9鈥?3.3%). The concentration ratios of 2-methyltetrols and levoglucosan in the gas phase to those in the particle phase were often close to or higher than unity in summer, indicating that these polar species are semi-volatile and their G/P partitioning should be considered when applying particle-phase data for source apportionment. The K_p,OM^m values of 2-methyltetrols had small variability in summer Denver, which was ascribed to large variations in concentrations of particulate organic matter (5.14 卤 3.29 渭g m^鈥?) and small changes in ambient temperature (21.8 卤 4.05 掳C). The regression between log K_p,OM^m and log K_p,OM^t suggested that the absorptive G/P partitioning theory could reasonably predict the measured G/P partitioning of levoglucosan in ambient samples.