Chloroform in the environment: occurrence,sources, sinks and effects

The chloroform flux through the environment is apparently constant at some 660±220 Gg yr⁻¹ (±1σ) and about 90% of the emissions are natural in origin: the largest single source being in offshore sea water (contributing 360±90 Gg yr⁻¹), with soil processes the next most important (220±100 Gg yr⁻¹). Other natural sources, mainly volcanic and geological, account for less than 20 Gg yr⁻¹. The non-natural sources total 66±23 Gg yr⁻¹ and are much better characterised than the natural sources. They are predominantly the result of using strong oxidising agent on organic material in the presence of chloride ion, a direct parallel with the natural processes occurring in soils.

Chloroform partitions preferentially into the atmosphere; the equilibrium distribution is greater than 99% and the average global atmospheric concentration has been calculated to be 18.5 pmol mol⁻¹. Atmospheric oxidation, the principal removal process, is approximately in balance with the identified source fluxes. Chloroform is widely dispersed in the aquatic environment (even naturally present in some mineral waters). Consequently, it is also widely dispersed in the tissue of living creatures and in foodstuffs but there is little evidence of bioaccumulation and the quantities in foodstuffs and drinking water are not problematical for human ingestion at the highest concentrations found. Definitive studies have shown that current environmental concentrations of chloroform do not present an ecotoxicological risk, even to fish at the embryonic and larval stages when they are most susceptible.

By virtue of the very small amounts that actually become transported to the stratosphere, chloroform does not deplete ozone materially, nor is it a photochemically active volatile organic compound (VOC). It has a global warming potential that is less than that of the photochemically active VOCs and is not classed as a greenhouse gas.     

石墨炉原子吸收直接测定大气颗粒物中的铅和锰

以少量HNO_3-HF-HClO_4消解粉尘滤膜,石墨炉原子吸收法测定铅和锰,进行了最佳条件选择,采用本法测定粉尘中的铅和锰,其回收率分别为87％～98％和94％～105％,用标准加入法检验结果吻合,方法变异系数分别为铅4.1％,锰3.7％。     

大气环境影响预测模式应用的几个问题

将当前大气环境影响预测模式应用中，对颗粒污染物地面浓度模式修正，气态污染物地面最大浓度模式选用和求长方法，静风条件下地面浓度模式及其参数选择等方面容易出现疏忽或失误的问题提出了来讨论，并提出了正确的应用方法。     

距离加权插值法在大气环境监测数据处理中的应用

探讨了用距离加权插值法对大气环境监测数据进行网格图形化处理，并对算法过程进行研究，从而得到区域大气环境污染物浓度分布等值线图，以便于更简明、直观地进行分析评价。     

山东省城市大气降水pH值观测结果及其初步分析

通过对山东省十七个主要城市2003年大气降水观测数据的统计分析,对大气降水pH值的时空分布特征和酸雨频率进行了分析。结果表明,山东省酸雨主要出现在秋季和冬季;鲁北平原、鲁中南的莱芜地区,胶东半岛地区频率较高。从酸雨与气象条件的初步分析得出,风速越小时,地面风对酸雨的贡献就相对增大;冬季接地逆温的存在为酸雨形成提供了极其有利的条件。文章并从气象角度对酸雨成因机理作了初步的分析。     

Project of an Air Quality Monitoring Network for Industrial Site in Italy

In this paper results concerning project of an atmospheric monitoring network applied to an area of south of Italy carried out using chemical measurement campaigns (for traffic emissions characterisation couple with diffusional simulation of industrial pollutant emissions will be presented. The area selected is characterised by an high concentration of high environmental impacting industrial activities, with also high concentration of urban settlement and vehicular traffic. A comprehensive definition of all the monitoring system to be installed in order to have a correct monitoring system for the all province will be described and discussed.     

运用系统决策方法优选大气污染治理方案

本文运用层次分析和多目标决策技术来量化大气污染治理方案的综合效益,从而为最佳治理方案的选取提供了科学依据.     

在用车加装催化净化器的技术分析

安装催化净化器是目前控制机动车污染排放最有效的技术手段之一,而用于在用车排放污染的治理,将会遇到很多具体的技术问题。文章从理论与技术两方面来分析如何确保在用车加装催化净化器后有良好的净化效果,根据国外的实践经验来探讨加装催化净化器的环境效益与经济费用,以及国产在用车加装催化净化器的可行性。     

第二代空气质量模式HPDM的分析改进

对第二代空气质量模式一混合烟气扩散模式ＨＰＤＭ进行了分析，通过与ＰＰＳＰ、ＡＭＳ、ＧＢ等模式的对比和工程验算，提出了ＨＰＤＭ在计算混合层高度和处理烟气穿透方面的缺陷，并提出了相应的改进方案。计算结果表明：改进以后的模式性能更加完善，其预测结果总体上与改进前相当，但在夜间不出现浓度值的大幅度跃变，在部分局部穿透情况下不出现极端高浓度。     

大气颗粒物对降水酸度缓冲能力的估算方法探讨

在按降雨天气系统和雨前大气颗粒物不同平衡状念对雨样进行分类的基础上,建立了大气颗粒物对降水酸度缓冲作用的计算公式。实例计算表明,计算酸度与清洁点上实测酸度十分一致;颗粒物所消耗的[H~+]占实测[H~+]的24％,占总缓冲能力的44％。