| 近3年太原市夏季降水的化学特征研究 |
| 摘要点击 4051 全文点击 1678 投稿时间：2014-07-29 修订日期：2014-09-23 |
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| 中文关键词 太原 降水 化学特征 中和因子 后向轨迹 |
| 英文关键词 Taiyuan precipitation chemical characteristics neutralization factors backward trajectory |
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| 中文摘要 |
| 本研究采集了2011~2013年太原市夏季66场降水样品,分析了pH值、电导率和水溶性阴阳离子,探讨了太原市夏季降水的化学组成及来源. 结果表明,近3年太原市夏季降水pH值范围为4.63~8.02,加权平均值为5.19; 2011~2013年酸雨频率分别为37.0%、31.2%和17.4%. 太原夏季降水的化学组成以SO42-、NO3-、Ca2+和NH4+为主,阴离子SO42-和NO3-加权平均浓度分别占阴离子总浓度的67.2%和22.0%,阳离子Ca2+和NH4+加权平均浓度分别占阳离子总浓度的55.1%和29.0%; 降水中SO42-、NO3-、Ca2+和NH4+浓度水平随年度有明显的下降趋势. 近3年SO42-/NO3-的当量浓度比分别为2.97、3.06和3.08,平均值为3.02,说明太原市夏季酸性降雨类型为硫酸和硝酸复合型,且硝酸盐的贡献逐年增强. 通过中和因子分析,表明太原市夏季降水中Ca2+和NH4+对酸性中和起主导作用,但Mg2+的作用不可忽略. 太原市夏季降水中水溶性化学组分主要与燃煤排放有关; 结合气团的后向轨迹分析表明太原市夏季降水主要受山西省内南部低空运行的短距离输送气团的控制; 西南和东南气团是太原市夏季降水中水溶性化学组分的主要来源. 为了有效改善太原市的空气质量,太原南部及本地焦化企业和燃煤电厂污染物的排放应给予关注. |
| 英文摘要 |
| The chemical characteristics of the precipitation in Taiyuan in summer of 2011-2013 were investigated. The results showed that the pH of precipitation varied from 4.63 to 8.02 with a volume-weighted mean of 5.19. The frequency of acid rain was 37.0%, 31.2% and 17.4%, respectively, in 2011-2013. SO42- and NO3- were dominant anions in the precipitation, which accounted for 67.2% and 22.0% of the total anions, respectively. While Ca2+ and NH4+ were dominant cations in the precipitation, which accounted for 55.1% and 29.0% of the total cations, respectively. There were evident declining trends in the concentration of SO42-, NO3-, Ca2+ and NH4+ in the precipitation over the study period. The mean ratio of SO42- to NO3- in summer precipitation was 3.02, indicating that the acid rain was of sulfuric-nitrous mixed type, however, NO3- was very important for the acidity of rain water. Neutralization factors (NF) were calculated to show that Ca2+ and NH4+ were the predominant neutralizers in rainwater samples, but Mg2+ could also not be negligible. The correlation analysis revealed that coal combustion was the dominant source of chemical composition of rainwater in summer of Taiyuan. The back trajectory analysis demonstrated that the air pollutants of Taiyuan were from the local plants and the coal coking plants in the southern Taiyuan basin. However, to improve the air quality in this city, both industrial emissions from thermal power plants and coal coking plants in Taiyuan basin need to be controlled. |
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