Hygroscopic properties of sodium and potassium salts as related to saline mineral dusts and sea salt aerosols

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction. Temperature dependence of deliquescence RH (DRH) values for five of those salts was also investigated, which are comparable to those in literature within 1%–2% RH, most showing negative dependence on temperature. Hygroscopic growth curves of real-world soil and sea salt samples were also measured. The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition. The substantial amounts of water-soluble ions, including Na⁺ and K⁺, in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH (>80%) conditions. For three less-hygroscopic dust samples, however, measurements showed higher water uptake ability than that predicted by the thermodynamic model. The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH. The results of this study provide a comprehensive characterization of the hygroscopicity of Na- and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.     

焦作市采暖期大气降尘重金属的分布特征和健康风险评估

本文在对焦作市采暖期大气降尘样品中重金属含量进行测定的基础上,研究其分布特征并评估其导致的健康风险。结果表明,焦作市采暖期大气降尘重金属Cr、Co、Ni、Cu、As、Cd、Pb、Zn的含量范围为14.18~136.97、3.40~13.98、15.57~63.28、15.05~150.00、19.86~71.49、1.23~22.36、105.52~213.18、487.00~2180.00 mg/kg,重金属元素含量均服从对数正态分布。各重金属非致癌风险暴露剂量的排序为Zn>Pb>Cr>Cu>Ni>As>Co>Cd。3种途径的暴露剂量均为儿童大于成人,且儿童的非致癌危害商大于成年人;儿童和成人的致癌风险Risk排序均为Cr>As>Co>Cd>Ni,致癌风险均低于10-6~10-4,暂无致癌风险。     

Dust storm frequency and its relation to climate changes in Northern China during the past 1000 years

Dust storm events and their relation to climate changes in Northern China during the past 1000 years were analyzed by using different paleoclimate archives such as ice cores, tree rings, and historical documents. The results show that in the semiarid region, the temperature and precipitation series were significantly negatively correlated to the dust storm frequency on a decadal timescale. Compared with temperature changes, however, there was a closer correlation between precipitation changes and dust storm events on a centennial timescale. At this timescale, precipitation accounts for 40% of the variance of dust fall variations during the last 1700 years, inferring precipitation control on the formation of dust storms. In the western arid region, both temperature and precipitation changes are important forcing factors for the occurrence of dust storms in the region on a centennial timescale. In the eastern arid region, the relationship between dust storm events and climate changes are similar like in the semiarid region. As a result, the effects of climate change on dust storm events were manifested on decadal and centennial timescales during the last millennium. However, there is a phase shift in the relation between climate change and the dust storm frequency. A 1400 years reconstruction of the strength of the Siberian High reveals that long-term variations of spring Siberian High intensity might provide a background for the dynamic conditions for the frequency of historical dust storm events in Northern China.     

煤矿综采工作面防尘技术研究现状及趋势

随着煤矿机械化程度和开采强度的不断加大,导致综采工作面的产尘强度及作业环境中粉尘浓度也愈来愈大,严重影响煤矿安全生产和作业人员身体健康.本文主要介绍最近几年国内外综采工作面防尘技术方面的研究成果,总结提高综采工作面防尘效果的技术研究基本趋势,期望为我国煤矿综采工作面粉尘防治提供多种方法和手段.     

地下金属矿山安全评价体系的探讨

对矿山实行安全评价是确保安全生产的重要措施。根据地下金属矿山生产工艺的特点，分析发生事故的原因及影响因素，以定量分析的方法，从企业管理、工程设计、人员配备、环境条件等方面进行安全评价，提出评价体系，系统而直观地反映企业生产安全程度。     

Tropical deciduous forests and the adivasi. Indigenous traditions as response to leaf fall in Bastar, India

This article draws attention to the crucial link between the tropical deciduous forest ecosystem and the lifestyle of the adivasi (indigenous) people. Taking the case of Bastar District in Chhattisgarh, Central India, an analysis is made of the various commonly used wild plants, their deciduous habit, and the adivasi calendar that regulates the peoples’ use of these plants. By examining the specific seasonal patterns of leaf fall of plants and the dates set for the commencement of their use, the article shows that there is an implicit relation between adivasi festivals and the deciduous character of Bastar's forests.     

装饰不锈钢管抛光粉尘的治理

通过装饰不锈钢管抛光粉尘治理实例，介绍除尘系统密闭罩设计、除尘以及装置的降噪、防腐、防磨。     

厦门市尘污染的主要原因及防治措施

分析了厦门市尘污染现状，探讨了造成尘污染的主要原因，并提出防治措施．     

水泥散装率变化对粉尘排放的影响

依据历史数据和有关部门提供的数据,建立了水泥粉尘排放的基本计算方法,采用投入产出模型、水泥使用分配模型和生产粉尘排放系数模型,测算了不同散装率水平下粉尘排放量的总体规模。当水泥产量增加到7×108t时,如果水泥散装率保持在20％的情况下,粉尘排放量为1988万t,如果散装率提高到40％,则粉尘排放量则降低到1598万t,降低幅度为390万t。     

用水淬煤渣混合料代替碎石作为集装箱货场硬化面基层的试验研究

本文通过对热电厂的工业废料──水淬煤渣与土、石灰组成混合料的各种物理、力学性能的试验研究，指出用其代替碎石作为集装箱场硬化面基，不仅可以减少工业废料对城市的污染，而且还可以降低工程造价．