The study of TSP, PM(2.5-10) and PM2.5 during Taiwan Chi-Chi Earthquake in the traffic site of central Taiwan, Taichung

Ambient particle concentration was taken on the traffic sampling site over the Chung-Chi Road over bridge (CCROB) in front of Hungkuang Institute of Technology (HKIT). The sampling time was from August 1999 to December 1999. During the sampling period, Taiwan's biggest earthquake in more than a century registered 7.3 on the Richter scale (Taiwan Chi-Chi Earthquake). Besides, there were more than 20,000 aftershocks that followed the Taiwan Chi-Chi Earthquake within three months. Thus, the PM2.5, PM(2.5-10) particle concentrations were also collected then and compared with total suspended particle (TSP) in this study. The average PM(2.5-10), PM2.5 and TSP concentrations are 24.6, 58.0 and 106 microg/m3, respectively, after the Taiwan Chi-Chi Earthquake. The average TSP concentrations before and after Taiwan Chi-Chi Earthquake were 70 and 127 microg/m3, respectively. It is clearly shown that the average concentration of TSP after Taiwan Chi-Chi Earthquake was about 1.8 times as that of TSP concentration before Taiwan Chi-Chi Earthquake in the traffic site of central Taiwan. And the ratios of PM2.5/PM(2.5-10), PM2.5/PM10 and PM2.5/TSP are 2.2%, 67.2%, 38.9%, respectively. The results also indicated about Chi-Chi fine particle concentration (PM25) and the TSP increases in the traffic site of central Taiwan after Taiwan Chi-Chi Earthquake.     

Photochemical production of ozone and control strategy for Southern Taiwan

An observation-based method (OBM) is developed to evaluate the ozone (O₃) production efficiency (O₃ molecules produced per NO_x molecule consumed) and O₃ production rate (P(O₃)) during a field campaign in southern Taiwan. The method can also provide an estimate of the concentration of OH. A key step in the method is to use observed concentrations of two aromatic hydrocarbons, namely ethylbenzene and m,p-xylene, to estimate the degree of photochemical processing and amounts of photochemically consumed NO_x and NMHCs by OH. In addition, total oxidant (O₃+NO₂) instead of O₃ itself turns out to be very useful for representing ozone production in the OBM approach. The average O₃ production efficiency during the field campaign in Fall (2003) is found to be about 10.2±3.9. The relationship of P(O₃) with NO_x is examined and compared with a one-dimensional (1D) photochemical model. Values of P(O₃) derived from the OBM are slightly lower than those calculated in the 1D model. However, OH concentrations estimated by the OBM are about a factor of 2 lower than the 1D model. Fresh emissions, which affect the degree of photochemical processing appear to be a major cause of the underestimate. We have developed a three-dimensional (3D) OBM O₃ production diagram that resembles the EKMA ozone isopleth diagram to study the relationship of the total oxidant versus O₃ precursors. The 3D OBM O₃ production diagram suggests that reducing emissions of NMHCs are more effective in controlling O₃ than reducing NO_x. However, significant uncertainties remain in the OBM, and considerable more work is required to minimize these uncertainties before a definitive control strategy can be reached. The observation-based approach provides a good alternative to measuring peroxy radicals for evaluating the production of O₃ and formulating O₃ control strategy in urban and suburban environments.     

Vertical distribution of polycyclic aromatic hydrocarbons in atmospheric boundary layer of Beijing in winter

Air samples were collected using active samplers at various heights of 8, 15, 32, 47, 65, 80, 102, 120, 140, 160, 180, 200, 240, 280 and 320 m on a meteorological tower in an urban area of Beijing in two campaigns in winter 2006. Altitudinal distributions of polycyclic aromatic hydrocarbons (PAHs) in atmospheric boundary layer of Beijing in winter season were investigated. Meteorological conditions during the studied period were characterized by online measurements of four meteorological parameters as well as trajectory calculation. The mean total concentrations of 15 PAHs except naphthalene of gaseous and particulate phase were 667±450 and 331±144 ng m⁻³ in January and 61±19 and 29±6 ng m⁻³ in March, respectively. Domestic coal combustion and vehicle emission were the dominant PAH sources in winter. Although the composition profiles derived from the two campaigns were similar, the concentrations were different by one order of magnitude. The higher concentrations in January were partly caused by higher emission due to colder weather than March. Moreover, weak wind, passing through the city center before the sampling site, picked up more contaminants on the way and provided unfavorable dispersion condition in January. For both campaigns, PAH concentrations decreased with heights because of ground-level emission and unfavorable dispersion conditions in winter. The concentration ratio of PAHs in gas versus solid phases was temperature dependent and negatively correlated to their octanol–air partition coefficients.     

Utilization of agricultural waste corn cob for the preparation of carbon adsorbent

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K2CO3) and carbon dioxide (CO2). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO2 was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption-desorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO2 is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m2/g and about 1.0 cm3/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K2CO3 and CO2 was suitable for the preparation of large-surface-area activated carbons.     

富勒烯对PCR反应的抑制作用

以110bp单链DNA为模板,研究富勒烯(C60)对聚合酶链式反应(polymerase chain reaction,PCR)的影响.实验结果表明,随着C60浓度的增加,PCR反应被显著抑制;将Taq DNA聚合酶、单链DNA模板与C60孵育后,其PCR扩增产物均显著减少;增加PCR反应体系中的Taq DNA聚合酶量,可消除C60的抑制作用,但增加起始单链DNA模板的数量,效应不明显,上述研究结果说明,C60不仅可抑制Taq DNA聚合酶活性,同时对DNA模板也具有一定的损伤作用.     

EDTA-assisted phytoextraction of lead from lead-contaminated soils by Echinochloa crusgalli var. frumentacea

The herbaceous plant Echinochloa crusgalli var. frumentacea is highly resistant to a wide range of heavy metal concentrations. In this study we tested the phytoextraction capacity of E. crusgalli var. frumentacea. Specifically, we compared the effect of EDTA on lead (Pb) accumulation in two groups of plants: those sown in lead contaminated soil and those transplanted to the contaminated soil as seedlings. The result of the time development of the Pb concentrations in the plants in the seedling and seed groups shows that for the seedling group, the effect of adding EDTA to the Pb-contaminated soil was even more pronounced in the shoots than the roots, which showed Pb concentrations 32-fold higher. Compared to the seedling group, the Pb concentrations in the roots of plants in the seed group were approximately 5 times higher in controls and 2 to 10 times higher in the presence of EDTA. Collectively, these results might be considered that EDTA elevates the bioavailability of Pb in soil and this native species is particularly suited to use in Pb phytoextraction.     

粉尘云最小点火能量的研究现状

通过大量文献调研,从3个方面整理并分析了近年来关于粉尘云最小点火能量的研究现状,即粉尘云着火及火焰传播过程的理论模拟、纳米粉体着火敏感特性的实验研究和可燃粉尘的惰化技术,并在此基础上提出进一步的研究建议,为相关理论技术的发展提供参考。     

中国旅游业全要素碳生产率动态演进及其影响因素

为探清中国旅游业全要素碳生产率（total factor carbon productivity,TFCP）增长演化特征及影响因素,运用Malmquist-Luenberger指数测算2000—2017年中国30个省（自治区、直辖市）旅游业TFCP及其分解（不含港澳台及西藏自治区数据,下同）,借助核密度估计揭示其动态演进趋势,并建立面板数据模型探究影响旅游业TFCP的关键因素.结果表明:①2000—2017年,中国旅游业TFCP平均增长率为6.2%,呈现中部高于东部、东部高于西部的空间增长格局,且技术进步是其增长的主要驱动力.②中国共有28个省份的旅游业TFCP呈现正增长,其中吉林省的增幅最高,而青海省、宁夏回族自治区旅游业TFCP出现下降;旅游业碳排放技术“创新者”主要为天津市、河南省、山西省、上海市和内蒙古自治区.③旅游业累积TFCP和累积技术进步均存在明显提升,但二者省际差距有所扩大;而累积技术效率虽然省际差距在缩小,但效率提高幅度不明显,且呈一定倒退趋势.④全国范围内,旅游业经济规模、产业结构和对外开放程度分别在1%、1%和10%的显著性水平上正向促进旅游业TFCP,旅游业能源强度、旅游业碳排放结构及城镇化水平在1%的显著性水平上负向影响旅游业TFCP,环境规制对其影响不显著.研究显示,中国旅游业TFCP虽波动性较大,但整体呈增长趋势,技术进步的贡献高于技术效率的贡献,今后在依靠技术进步提升旅游业TFCP的同时,更要注重改善技术效率.      

伊逊河流域总磷污染来源解析

2017—2018年TP成为滦河一级支流伊逊河流域的主要污染因子,部分国控断面水质主要以GB 3838—2002《地表水环境质量标准》Ⅳ类、Ⅴ类为主.为开展伊逊河TP污染定量识别研究,在2017年和2018年伊逊河流域水体TP污染时空特征分析的基础上,从流域磷铁矿工业污染、城镇生活污水、雨水径流、河道内源释放以及农业非点源等方面开展TP污染研究.结果表明:①伊逊河流域上游至下游TP污染程度呈加剧恶化趋势,上游唐三营控制单元污染较轻,下游李台控制单元TP污染最重;丰水期TP污染较重,枯/平水期污染较轻;从年度看,2017年TP污染严重,2018年年均ρ（TP）下降了50.00%.②2017年、2018年伊逊河流域TP污染来源差异显著,2017年磷输入主要来自于磷铁矿工业污染,占比为33.46%;选矿企业整改后,2018年磷输入主要来源变为畜禽养殖和城镇生活污染,二者占比合计为59.91%.针对伊逊河流域TP污染特征,提出伊逊河流域TP污染控制建议:加强选矿企业环境监管,进一步完善监管体系;加强流域水土流失治理,实施矿山披绿;大力实施绿色农业工程,加强畜禽养殖布局优化.      

Seasonal and spatial distributions of euphotic zone and long-term variations in water transparency in a clear oligotrophic Lake Fuxian, China

To assess the seasonal and spatial variations and long-term trends in water optical properties in Lake Fuxian, investigations based on field work in four seasons and a long-term analysis of data from 1980 to 2014 were conducted. The results show that there was no significant variation in the euphotic depth(Z_(eu)) across the four seasons, and no significant correlations between Z_(eu) and potential influencing factors in seasons other than summer, suggesting that the water itself may be a major factor regulating the Z_(eu)in general. Nevertheless, significant differences in Z_(eu) between the north region(NR) and the south region(SR) were observed in all seasonal tests except spring. This finding relates to a higher abundance of chromophoric dissolved organic matter(CDOM) in the NR due to runoff, especially in the rainy seasons(summer and autumn).CDOM and its terrigenous component had an important impact on Z_(eu)in summer, with the highest precipitation, and impacts from suspended solids and non-algal particles were also found in the NR in summer. The Secchi disk depth in the lake decreased clearly over the years,with significantly negative correlations with the increasing permanganate index and air temperature, implying that organic contaminants(CDOM and/or phytoplankton) are important regulators of water transparency. We estimate that the combined effects of climate warming and changes in land use and land cover are also indirect regulating factors. These findings should be considered in the protection of Lake Fuxian, owing to the importance of light penetration in aquatic ecosystems.