Seasonal and diurnal variations of submicron organic aerosol in Tokyo observed using the Aerodyne aerosol mass spectrometer
Seasonal and diurnal variations of submicron organic aerosol in Tokyo observed using the Aerodyne aerosol mass spectrometer
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DOI：
10.1029/2005jd006515
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发表时间：
2006-06
影响因子：
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通讯作者：
N. Takegawa;T. Miyakawa;Y. Kondo;J. Jimenez;Q. Zhang;D. Worsnop;M. Fukuda
中科院分区：
文献类型：
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作者：
N. Takegawa;T. Miyakawa;Y. Kondo;J. Jimenez;Q. Zhang;D. Worsnop;M. Fukuda
[1]在东京的一个城市站点（35°39′N，139°40′E）进行了痕量气体和气溶胶的原位测量。在夏季（2003年7月至8月），秋季（2003年9月至10月）和冬季（2003年2月和2004年1月至2月）获得的数据用于本分析。使用Aerodyne气溶胶质谱仪（AMS）测量非耐火（在600°C高真空下蒸发）亚微米气溶胶的尺寸分辨化学组成。有机物被认为是占主导地位的组成部分（总的非耐火气溶胶质量的40-60%）在所有时期。有机气溶胶（OA）是通过与AMS质谱中的一氧化碳（CO）以及脂肪族和含氧有机化合物碎片的相关性进行分类的。燃烧相关的有机气溶胶（燃烧OA）被定义为主要的有机气溶胶（POA）部分，通过与CO的线性相关性确定。过量的有机气溶胶（过量OA）通过从总OA中减去燃烧OA和背景OA来定义。燃烧OA和过量OA分别与烃类有机气溶胶（HOA）和含氧有机气溶胶（OOA）显示出良好的相关性（r2 = 0.65-0.85），这些气溶胶来自自定义的主成分分析。在夏季期间，估计的过量OA浓度表现出明显的日变化，并与臭氧（O3）在白天。平均而言，燃烧OA没有表现出明显的昼夜变化的夏季，秋季和冬季期间，而过量的OA显示出明确的昼夜模式（白天峰值在1300 LT）。在白天的峰值过剩的OA被发现是在几乎相同的浓度为燃烧OA的所有季节，这表明显着的二次有机气溶胶（SOA）的形成发生在白天的整个测量期间。
[1] In situ measurements of trace gases and aerosols were conducted at an urban site in Tokyo (35°39′N, 139°40′E). The data obtained in summer (July–August 2003), fall (September–October 2003), and winter (February 2003 and January–February 2004) are used for the present analysis. Size-resolved chemical composition of nonrefractory (vaporized at 600°C under high vacuum) submicron aerosol was measured using an Aerodyne aerosol mass spectrometer (AMS). Organics are found to be the dominant component (40–60% of total nonrefractory aerosol mass) in all periods. Organic aerosol (OA) is classified by correlation with carbon monoxide (CO) and fragments of aliphatic and oxygenated organic compounds in the AMS mass spectra. Combustion-related organic aerosol (combustion OA) is defined as the primary organic aerosol (POA) fraction, as determined by a linear correlation with CO. Excess organic aerosol (excess OA) is defined by subtracting the combustion OA and the background OA from the total OA. The combustion OA and excess OA show good correlation (r2 = 0.65–0.85) with hydrocarbon-like organic aerosol (HOA) and oxygenated organic aerosol (OOA), respectively, which were derived from a custom principal component analysis. In the summer period the estimated excess OA concentrations show distinct diurnal variations and correlate with ozone (O3) during daytime. On average, the combustion OA does not exhibit a distinct diurnal variation for the summer, fall, and winter periods, while the excess OA shows a clear diurnal pattern (daytime peak at ∼1300 LT). At the daytime peak the excess OA is found to be at nearly the same concentration as the combustion OA for all seasons, suggesting that significant formation of secondary organic aerosol (SOA) occurred in daytime throughout the measurement period.