Photochemical Aging of Polycyclic Aromatic Hydrocarbons on Asian Particulate Matter

本研究的主要目的是了解光化学老化对亚洲颗粒物（PM）在跨太平洋大气输送到美国西海岸过程中多环芳烃（PAH）组成的影响。研究人员推测，硝基多环芳烃（NPAHs）和氧基多环芳烃（OPAHs）是在亚洲PM的跨太平洋大气运输过程中形成的。本研究的具体目的是利用气溶胶反应器在实验室中研究分级亚洲PM的光化学老化。虽然不完全燃烧会生成未取代的多环芳烃，但硝基多环芳烃和氧基多环芳烃都是在白天不完全燃烧和未取代多环芳烃与光化学反应物（臭氧、羟基自由基和氮氧化物）的直接排放以及在夜间与硝酸盐自由基的反应中产生的。在跨太平洋运输过程中，多环芳烃很可能与这些氧化剂反应形成NPAH和OPAH。来自亚洲和俄勒冈州的含有亚洲PM的现有气溶胶样本将用于多环芳烃老化的实验室研究。将与波尔多大学的同事合作，对气溶胶样品进行多环芳烃的化学氧化，并随后进行分析。该活动包括培训一名研究生，并继续包括来自中俄勒冈社区学院（COCC）的一名教员和她的本科生参与研究。COCC本科学生将学习对大型研究数据集进行统计操作，以及了解使用质谱法识别和量化多环芳烃的过程。最后，研究结果可能对亚洲燃烧排放控制方面的全球环境政策产生影响。

The primary objective of the research is to understand the effect of photochemical aging on the polycyclic aromatic hydrocarbon (PAH) composition of Asian particulate matter (PM) during trans-Pacific atmospheric transport to the U.S. West Coast. The principal investigators hypothesize that nitro-PAHs (NPAHs) and oxy-PAHs (OPAHs) are formed on Asian PM during trans-Pacific atmospheric transport. The specific goal of this research is to use aerosol reactors to study the photochemical aging of size-fractionated Asian PM in the laboratory.While incomplete combustion results in the formation of unsubstituted PAHs, both nitro-PAHs and oxy-PAHs result from both direct emission during incomplete combustion and reactions of unsubstituted PAHs with photochemical reactants (ozone, hydroxyl radical and nitrogen oxides) during the daytime and reactions with nitrate radicals at night. It is likely that PAHs react with these oxidants during trans-Pacific transport to form NPAH and OPAH. Existing aerosol samples from both Asia and Oregon, containing Asian PM, will be used for the laboratory studies of PAH aging. Chemical oxidation of PAHs on aerosol samples will be carried out and subsequently analyzed in collaboration with colleagues at the University of Bordeaux.The activity includes training a graduate student and continued inclusion of a faculty member from Central Oregon Community College (COCC) and her undergraduate students in the research. COCC undergraduate students will learn to conduct statistical manipulations of a large research data set, as well as understand the process of identifying and quantifying PAHs using mass spectrometry. Finally, the results of the research could have global environmental policy implications with regard to combustion emission controls in Asia.