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Source and source strength determination of atmospheric organic acids

大气有机酸的来源和来源强度测定

基本信息

批准号：
07454142
负责人：
SAKUGAWA Hiroshi
金额：
$ 4.74万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

(1) Concentrations of rain and dew organic acids such as formic, acetic and oxalic acids in the Hiroshima prefecture, western Japan, during 1995-1997 were determined by ion chromatography. Concentration range of formic, acetic and oxalic acids detected in rain and dew was 0-25,0-49 and 0-3.4mu M,respectivesy. The percentage of free acidity generated from organic acids to that from the total acidic substances was 2.9-7.1% and 14% in rain and dew, respectivesy, implying that organic acids contribute to the acidification of rain and dew.(2) Measurements of organic acid concentrations in car exhausts and combustion gases of incinerator were carried out to evaluate the role of anthropogenic activities in the production of atmospheric organic acids. The results indicate that these fossil fuel combustion gases contain from ppbv level to hundreds ppbv level of organic acids and the emission rates of these organic acids into the atmosphere are calculated to be from tons to hundreds tons per year in the Hiroshima fecture.(3) To elucidate the source and source strength of atmospheric organic acids, carbon stable isotopic ratio of organic acids was determined. Authentic samples of organic acids were first examined to determine if the change of isotopic ratio occurs during lon chromatographic separation and it was found to occur only minor isotopic ratio change. Thus the measurement of stable isotopic ratio of organic acids should be an useful method to determine the origin of organic acids.

(1)采用离子色谱法测定了1995 ~ 1997年日本广岛地区雨露有机酸甲酸、乙酸和草酸的浓度。雨露中甲酸、乙酸和草酸的检测浓度范围分别为0 ~ 25 μ M、0 ~ 49 μ M和0 ~ 3.4 μ M。雨水和露水中有机酸产生的游离酸度占总酸性物质的比例分别为2.9-7.1%和14%，说明有机酸对雨水和露水的酸化有一定的促进作用。(2)通过对汽车尾气和焚化炉燃烧气体中有机酸浓度的测定，评价了人为活动对大气有机酸生成的影响。结果表明，这些化石燃料燃烧气体中有机酸的含量在ppbv到数百ppbv之间，而这些有机酸在广岛地区每年向大气中的排放率在吨到数百吨之间。(3)为了阐明大气有机酸的来源和来源强度，测定了有机酸的碳稳定同位素比。首先对真实的有机酸样品进行了检查，以确定在色谱分离过程中是否发生了同位素比的变化，发现同位素比只发生了很小的变化。因此，测定有机酸的稳定同位素比值是确定有机酸来源的一种有效方法。