Source Apportionment of Polycyclic Aromatic Hydrocarbons in the Urban Atmosphere: A Comparison of Three Methods

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• 作者：Randolph K. Larsen ; III and Joel E. Baker
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：May 1, 2003
• 年：2003
• 卷：37
• 期：9
• 页码：1873 - 1881
• 全文大小：278K
• 年卷期：v.37,no.9(May 1, 2003)
• ISSN：1520-5851

文摘

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitouspollutants in urban atmospheres. Several PAHs are knowncarcinogens or are the precursors to carcinogenicdaughter compounds. Understanding the contributions ofthe various emission sources is critical to appropriatelymanaging PAH levels in the environment. The sources ofPAHs to ambient air in Baltimore, MD, were determined byusing three source apportionment methods, principalcomponent analysis with multiple linear regression, UNMIX,and positive matrix factorization. Determining the sourceapportionment through multiple techniques mitigatesweaknesses in individual methods and strengthens theoverlapping conclusions. Overall source contributionscompare well among methods. Vehicles, both diesel andgasoline, contribute on average 16-26%, coal 28-36%, oil15-23%, and wood/other having the greatest disparity of 23-35% of the total (gas- plus particle-phase) PAHs. Seasonaltrends were found for both coal and oil. Coal was the dominatePAH source during the summer while oil dominatedduring the winter. Positive matrix factorization was theonly method to segregate diesel from gasoline sources.These methods indicate the number and relative strengthof PAH sources to the ambient urban atmosphere. Aswith all source apportionment techniques, these methodsrequire the user to objectively interpret the resultingsource profiles.