Effects of combustion emissions from the Eurasian continent in winter on seasonal δ13C of elemental carbon in aerosols in Japan
Effects of combustion emissions from the Eurasian continent in winter on seasonal δ13C of elemental carbon in aerosols in Japan
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DOI：
10.1016/j.atmosenv.2011.05.015
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发表时间：
2012
影响因子：
5
通讯作者：
H. Kawashima;Yuya Haneishi
中科院分区：
文献类型：
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作者：
H. Kawashima;Yuya Haneishi
研究了2008年4月至2010年1月在日本秋田县采样的气溶胶中悬浮颗粒物（SPM， 100%截止空气动力直径为10μm的颗粒）和PM2.5（50%截止空气动力直径为2.5μm的颗粒）的浓度，以及SPM和PM2.5以及可能来源样品中单质碳（EC）的碳同位素比（δ13C）。我们还测定了SPM的离子含量，并估计了在研究期间到达秋田县的气团的反向轨迹。SPM浓度极低（年平均15.2μgm−3），呈春高冬低的趋势。我们将春季的SPM升高归因于亚洲大陆带来的沙尘暴。PM2.5年平均浓度为8.6μgm−3。源样品（汽柴油汽车尾气、壁炉烟尘、露天生物质燃烧排放物、街道粉尘、土壤、木炭和煤）的δ13C值在−34.7‰~−1.8‰之间。轻型车（- 24.4±0.7‰）和乘用车（- 24.1±0.6‰）烟灰的δ13C值与所有柴油车（- 24.3±0.3‰）烟灰的δ13C值非常相似。冬季SPM中δ13C较夏季富集，PM2.5中δ13C仅呈轻微的季节变化趋势。根据这些数据和源结果，我们假设冬季SPM和PM2.5 δ13C的富集是煤燃烧等海外燃烧过程的长期影响。此外，SPM的δ13C与SPM中的Cl−和Mg2+含量相关，表明海盐的影响。我们通过反轨迹分析验证了这一假设。结果表明，大陆对冬季SPM和PM2.5的EC有影响。
We investigated suspended particulate matter (SPM, particles with a 100% cut-off aerodynamic diameter of 10μm) and PM2.5 (particles with a 50% cut-off aerodynamic diameter of 2.5μm) concentrations in aerosols sampled in Akita Prefecture, Japan, from April 2008 to January 2010, and the carbon isotope ratios (δ13C) of elemental carbon (EC) in both SPM and PM2.5 and in samples from possible sources. We also determined the ion contents of SPM and estimated the back trajectories of air masses arriving at Akita Prefecture during the study period. The SPM concentration was very low (annual average, 15.2μgm−3), and it tended to be higher in spring and lower in winter. We attributed the higher SPM in spring to dust storms brought from the Asian continent. The average annual PM2.5 concentration was 8.6μgm−3. δ13C of source samples (gasoline and diesel vehicle exhaust, fireplace soot, open biomass burning emissions, street dust, soil, charcoal, and coal) ranged from −34.7‰ to −1.8‰. δ13C values of soot from gasoline light-duty (−24.4±0.7‰) and passenger vehicles (−24.1±0.6‰) were very similar to that of soot from all diesel vehicles (−24.3±0.3‰). δ13C was enriched in SPM in winter compared with summer values, moreover, only a slight seasonal trend was detected in δ13C in PM2.5. From these data and the source results, we hypothesized that the enrichment of δ13C of SPM and PM2.5 in winter was a long-range effect of overseas combustion processes such as coal combustion. In addition, δ13C of SPM was correlated with Cl−and Mg2+contents in SPM, suggesting the influence of sea salt. We verified this hypothesis by back trajectory analyses. The results indicated a continental influence effects on EC of SPM and PM2.5 in winter.