Characterization of the sources and processes of organic and inorganic aerosols in New York city with a high-resolution time-of-flight aerosol mass apectrometer
Characterization of the sources and processes of organic and inorganic aerosols in New York city with a high-resolution time-of-flight aerosol mass apectrometer
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DOI：
10.5194/acp-11-1581-2011
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发表时间：
2011-02
影响因子：
6.3
通讯作者：
Yele Sun;Qi Zhang;J. Schwab;K. Demerjian;W. Chen;M. Bae;H. Hung;O. Hogrefe;Brian P. Frank
中科院分区：
文献类型：
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作者：
Yele Sun;Qi Zhang;J. Schwab;K. Demerjian;W. Chen;M. Bae;H. Hung;O. Hogrefe;Brian P. Frank
抽象。2009年夏季，在纽约州纽约皇后学院进行的实地密集研究中，使用高分辨率飞行时间气溶胶质谱仪原位测量了亚微米气溶胶颗粒（PM 1）。有机气溶胶（OA）和硫酸盐是两个主要的物种，分别占54%和24%，总的PM 1质量。OA的平均质量粒度分布呈现出峰值约为150 nm（Dva）的小模式和内部与硫酸盐、硝酸盐和铵混合的累积模式（约550 nm）。由于光化学的产生，硫酸盐和OA的日循环在东部时间下午01：00-02：00之间达到峰值。NYC中OA的平均（±σ）氧碳比（O/C）、氢碳比（H/C）和氮碳比（N/C）分别为0.36（±0.09）、1.49（±0.08）和0.012（±0.005），对应于平均有机质碳比（OM/OC）为1.62（±0.11）。高分辨率质谱的正矩阵分解（PMF）确定了两个主要OA（POA）来源，交通和烹饪，以及三个次要OA（SOA）组分，包括高度氧化，区域性低挥发性含氧OA（LV-OOA; O/C = 0.63），氧化程度较低的半挥发性SV-OOA（O/C = 0.38）和独特的富氮OA（NOA; N/C = 0.053），其特征在于突出的CxH 2x + 2N+峰可能来自氨基化合物。我们的研究结果表明，烹饪和交通是两个不同的和质量等效的POA源在纽约市，共同贡献了约30%的总OA质量在这项研究中。OA的组成是占主导地位的次生物种，特别是在高PM事件。SV-OOA和LV-OOA平均分别占总OA质量的34%和30%。SOA在NYC中的化学演化似乎是随着从SV-OOA到LV-OOA的连续氧化而进行的，这进一步得到了O/C比逐渐增加和总OOA中H/C比同时降低的支持。NOA（OA的5.8%）的详细分析提出的证据表明，有机氮物种，如胺可能发挥了重要作用，在纽约市的OA的大气处理，可能涉及酸碱化学和光化学。此外，通过对气团轨迹和气溶胶光学厚度（AOD）卫星图像的分析，表明次生硫酸盐和老化OA的高潜在源区主要位于城市的西部和西南部。
Abstract. Submicron aerosol particles (PM1) were measured in-situ using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer during the summer 2009 Field Intensive Study at Queens College in New York, NY. Organic aerosol (OA) and sulfate are the two dominant species, accounting for 54% and 24%, respectively, of the total PM1 mass. The average mass-based size distribution of OA presents a small mode peaking at ~150 nm (Dva) and an accumulation mode (~550 nm) that is internally mixed with sulfate, nitrate, and ammonium. The diurnal cycles of both sulfate and OA peak between 01:00–02:00 p.m. EST due to photochemical production. The average (±σ) oxygen-to-carbon (O/C), hydrogen-to-carbon (H/C), and nitrogen-to-carbon (N/C) ratios of OA in NYC are 0.36 (±0.09), 1.49 (±0.08), and 0.012 (±0.005), respectively, corresponding to an average organic mass-to-carbon (OM/OC) ratio of 1.62 (±0.11). Positive matrix factorization (PMF) of the high resolution mass spectra identified two primary OA (POA) sources, traffic and cooking, and three secondary OA (SOA) components including a highly oxidized, regional low-volatility oxygenated OA (LV-OOA; O/C = 0.63), a less oxidized, semi-volatile SV-OOA (O/C = 0.38) and a unique nitrogen-enriched OA (NOA; N/C = 0.053) characterized with prominent CxH2x + 2N+ peaks likely from amino compounds. Our results indicate that cooking and traffic are two distinct and mass-equivalent POA sources in NYC, together contributing ~30% of the total OA mass during this study. The OA composition is dominated by secondary species, especially during high PM events. SV-OOA and LV-OOA on average account for 34% and 30%, respectively, of the total OA mass. The chemical evolution of SOA in NYC appears to progress with a continuous oxidation from SV-OOA to LV-OOA, which is further supported by a gradual increase of O/C ratio and a simultaneous decrease of H/C ratio in total OOA. Detailed analysis of NOA (5.8% of OA) presents evidence that organic nitrogen species such as amines might have played an important role in the atmospheric processing of OA in NYC, likely involving both acid-base chemistry and photochemistry. In addition, analysis of air mass trajectories and satellite imagery of aerosol optical depth (AOD) indicates that the high potential source regions of secondary sulfate and aged OA are mainly located in regions to the west and southwest of the city.