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Development of The Carbon-Containing Aerosol Measuring Method and Elucidation of The Characteristic Property

含碳气溶胶测量方法的研制及其特性的阐明

基本信息

批准号：
14048206
负责人：
SAKAMOTO Kazuhiko
金额：
$ 21.95万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2005
项目状态：
已结题

项目摘要

Major results investigated in this research project are summarized as shown below.Two mechanisms to induce high concentrations of SPM and PM_<2.5> were found : (i) an active photochemical process produced high concentrations of OC and sulfate, leading to a high concentration of (NH_4)_2SO_4 in the particles and to production of secondary organic aerosols ; (ii) stable meteorological conditions resulted in accumulation of primary particles, mainly emitted from vehicle exhaust, resulting in high concentrations of OC and EC.PM_<10> and PM_<2.5> collected at 200 m were lower than those collected on the ground. "Others" species defined as the difference between the total particle mass and the sum of the masses of the measured species dominantly accounted for the vertical difference in mass concentrations in summer, whereas EC and OC were the major contributors in winter. Vertical profiles of relative humidity observed simultaneously indicated that the higher concentrations of "others" speci … More es in the samples collected on the ground were probably caused by water having been absorbed by deliquescent components of the particles.Gas-particle distributions of semi-volatile bifunctional carbonyls sampled with a low-volume denuder and filter pack system were investigated. Comparing the average concentrations founded at Saitama and Meguro, glyoxylic acid concentrations were similar in both sites, though, glyoxal, methyl glyoxal and glycolaldehyde showed higher concentrations in the gaseous phase at Meguro and higher concentrations in the particulate phase at Saitama, suggesting a gas to particle conversion on their transport.Daily samples for PM_<10> were collected with FRM sampler during 1995-2004 at urban area in Sakai and analyzed for carbonaceous components. Yearly average concentrations during 1995-2004 decreased from 13.7 to 7.1μg-C/m^3for TC, 8.9 to 4.8 μg-C/m^3 for OC, and 4.8 to 2.3 μg-C/m^3 for EC. OC concentrations decreased considerably during 1995-1998 and steady decrease in EC concentrations was found during 2000〜2004. Less

主要研究结果如下：(1)活跃的光化学过程产生高浓度的有机碳和硫酸盐，导致颗粒物中高浓度的(NH_4)_2SO_4和二次有机气溶胶的产生；(2)稳定的气象条件导致初级颗粒物的积累，主要是汽车尾气排放的初级颗粒物，导致高浓度的OC和EC.PM&lt；10&gt；和PM&lt；2.5&gt；在200米处采集的土壤水分低于地面采集的土壤。“其他”物种被定义为总颗粒物质量与被测量物种质量之和之间的差异，这是夏季质量浓度垂直差异的主要原因，而EC和OC是冬季的主要贡献者。同时观测到的相对湿度垂直剖面表明，较高浓度的“其他”物种…地面采集的样品中ES较多的原因可能是水分被颗粒中的潮解组分吸收所致。研究了采用小体积剥离器和滤袋系统采样的半挥发性双官能团的气固两相分布。比较崎玉站和目黑站的平均浓度，乙二醛、甲基乙二醛和乙醇醛在目黑站的气相和颗粒相的浓度较高，说明它们在运输过程中有气体向颗粒的转化。1995-2004年间，用FRM采样器在酒井市区采集了PM_&lt；10和gt；的每日样本，并进行了碳质成分分析。1995年至2004年期间，TC、OC和EC的年平均浓度分别从13.7μg-C/m^3、8.9μg-C/m^3和4.8μg-C/m^3降至7.1μg-C/m^3、8.9至4.8 g-C/m^3、4.8至2.3 gC/m^3。1995-1998年间，有机碳浓度显著下降，2000-2004年期间，EC浓度稳步下降。较少