| 题名 | 大气羰基硫未知源探析 |
| 作者 | 程晔 |
| 学位类别 | 硕士 |
| 答辩日期 | 2014-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 牟玉静 |
| 关键词 | 羰基硫 人为源 民用煤炉 一氧化碳 排放因子 carbonyl sulfide anthropogenic sources residential coal combustion carbon monoxide emission factor |
| 其他题名 | Researches on unknown sources of atmospheric carbonyl sulfide |
| 学位专业 | 环境科学 |
| 中文摘要 | 羰基硫(COS)是在无火山爆发情况下平流层硫酸盐的主要来源，对全球太阳辐射及平流层臭氧损耗具有重要影响。然而，目前人们对于大气中COS源和汇的认识还存在很大的不确定性，且其源和汇强度存在不平衡。为此，本文基于北京市大气中COS的观测和华北地区冬季民用取暖煤炉COS排放测定，分析探讨了不同污染源对大气COS的贡献，主要取得了以下研究进展： 对研究组原有Tenax-GC吸附富集-六通阀进样-GC-FPD的分析方法进行了改进，显著提高了COS样品分析的可操作性、精度和重现性：进样成功率100%，重复进样的相对标准偏差小于1.11%；基于水体中COS紫外光化学产生现象，建立了一套水体中COS前体物测定装置，并对河水中COS的前体物进行了初步测定。 两年观测数据表明北京地区大气中COS存在明显的季节变化，春夏秋冬的平均浓度分别为：608±262 pptv, 372±115 pptv, 651±275 pptv 和 849±477 pptv。北京地区大气COS的季节变化可反映该地区COS源和汇强度的变化，即冬季取暖化石燃料的排放对大气COS具有明显贡献，而夏季植被及土壤对大气COS存在强吸收。基于观测数据的深入分析发现大气COS与CO的浓度呈现显著的线性相关，其斜率(ΔCOS/ΔCO)在5月到6月为0.72 pptv/ppbv (R2>0.66，P＜0.005)，10月到4月为0.14 pptv/ppbv (R2>0.68，P＜0.005)，表明北京地区大气中COS主要来源于与燃烧过程相关的排放，夏季显著的ΔCOS/ΔCO高比值主要归咎于机动车轮胎在较高温度和臭氧浓度下磨损导致额外COS排放。根据ΔCOS/ΔCO比值以及北京市CO的排放清单，估算了北京市大气COS总的人为源为0.53±0.02 Gg/year。 根据华北冬季农村取暖煤炉燃烧特征，测定了COS, CS2 和SO2的排放，发现COS和CS2的排放主要集中在添煤后不久的燃烧初期过程，而SO2的排放则集中在燃烧过程的中后期；计算了COS和CS2在完全燃烧阶段（集中在农民做饭期间）的排放因子分别为0.08±0.04 g COS kg-1 coal 和6.07±3.37 mg CS2 kg-1 coal，而在压火阶段分别为1.77±0.26 g COS kg-1 coal和66.2±26.1 mg CS2 kg-1coal，显然，民用取暖煤炉在长时间压火阶段对大气中COS具有显著贡献。采用统计年鉴中民用煤消耗量及本研究所获排放因子估算了中国民用煤炉COS和CS2的排放量分别为49.72±8.12 Gg yr-1和2.01±0.80 Gg yr-1，表明民用煤炉是大气COS的一种重要人为来源。 目前，关于民用煤炉COS排放的测定还未见报道，本论文的研究为更好的认识全球羰基硫的源和汇提供了新的数据基础和科学依据。 |
| 英文摘要 | Carbonyl sulfide (COS) is the dominated nonvolcanic source of the stratospheric aerosol which can reduce solar irradiation and make contribution to the stratospheric ozone destruction. Now, however, the estimation of the sources and sinks contains considerable uncertainties with an unbalanced budget of the sources and sinks. Therefore, in this dissertation, based on the observation of atmospheric COS in Beijing and the COS emission measurement from the residential coal stoves used for winter heating in North China, the contribution of various pollution sources to atmospheric COS were studied. The COS concentration analyze system, Tenax-GC cryogenic trapping- six-way valve sampling-GC FPD, has been improved with the enhancement of feasibility, accuracy and repeatability: Sampling rate is 100%, the relative standard deviation of repeated samplings is less than 1.11%. Based on the phenomenon that COS can be formed from natural water under UV, a COS precursor(s) analyze system has been designed. Several water samples have been analyzed. Two years measurement reveals that COS mixing ratios exhibited distinct seasonal variation, with average values of 608±262 pptv, 372±115 pptv, 651±275 pptv and 849±477 pptv for spring, summer, autumn and winter, respectively. The seasonal variation of COS reflected the variation of the strengths of the COS sources in Beijing that coal combustion for winter heating made distinct contribution to the amopheric COS and vegetation uptake was strong in summer. Based on the observation data, two types of significant linear correlations (R2>0.66) between COS and CO were found during the periods from May to June and from October to March, with slopes (ΔCOS/ΔCO) of 0.72 pptv/ppbv and 0.14 pptv/ppbv, respectively. It indicated the dominant anthropogenic sources of COS in Beijing were found to be combustion related. The remarkably high valueΔCOS/ΔCO ratios observed in summer were astributed to the vehicles tires wear emission in summer under high temperature and O3 concentration. The total anthropogenic emission of COS in Beijing was roughly estimated as 0.53±0.02 Gg/year based on local CO emission inventory. Based on the combustion charactors of the residential coal stoves used for winter heating in North China, the emission of COS CS2 and SO2 have been measured. The results shows that emission of COS and CS2 mainly concentrated at the beginning of the combustion just after coaling, while at middle and end periods for SO2. The emission factors of COS and CS2 have been calculated as 0.08±0.04 g COS kg-1 coal, and 6.07±3.37 mg CS2 kg-1 coal at full combustion process At damping down process the emission factors are 1.77±0.26 g COS kg-1 coal and 66.2±26.1 mg CS2 kg-1 coal repectively for COS and CS2. Obviously, long-time damping down process has ansignificant contribution to atmospheric COS. Based on the coal comsuption data from the statistical yearbook and the calculated emission factors, the total emissions of COS and CS2 from the residential coal stoves in China were calculated as 49.72±8.12 Gg yr-1 and 2.01±0.80 Gg yr-1, respectively. The results indicated the residential coal stove is an important anthropogenic source for COS in China. Until now, no study on the COS emission from residential coal stoves has been reported. This study provided further scientific evidences to better understand the global sources and sinks of carbonyl sulfide. |
| 公开日期 | 2015-06-16 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/13487]  |
| 专题 | 生态环境研究中心_大气环境科学实验室 |
| 推荐引用方式 GB/T 7714 | 程晔. 大气羰基硫未知源探析[D]. 北京. 中国科学院研究生院. 2014. |
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