Pollution characteristics of ambient volatile organic compounds (VOCs) in the southeast coastal cities of China

With the rapid urbanization, the southeast coastal cities of China are facing increasing air pollution in the past decades. Large emissions of VOCs from vehicles and petrochemical factories have contributed greatly to the local air quality deterioration. Investigating the pollution characteristics of VOCs is of great significance to the environmental risk assessment and air quality improvement. Ambient VOC samples were collected simultaneously from nine coastal cities of southeast China using the Tedlar bags, and were subsequently preprocessed and analyzed using a cryogenic preconcentrator and a gas chromatography–mass spectrometry system, respectively. VOC compositions, spatial distributions, seasonal variations and ozone formation potentials (OPFs) were discussed. Results showed that methylene chloride, toluene, isopropyl alcohol and n-hexane were most abundant species, and oxygenated compounds, aromatics and halogenated hydrocarbons were most abundant chemical classes (62.5–95.6 % of TVOCs). Both industrial and vehicular exhausts might contribute greatly to the VOC emissions. The VOC levels in the southeast coastal cities of China were sufficiently high (e.g., 6.5 μg?m^?3 for benzene) to pose a health risk to local people. A more serious pollution state was found in the southern cities of the study region, while higher VOC levels were usually observed in winter. The B/T ratio (0.26?±?0.09) was lower than the typical ratio (ca. 0.6) for roadside samples, while the B/E (1.6–7.6) and T/E (7.2–26.8) ratios were higher than other cities around the world, which indicated a unique emission profile in the study region. Besides, analysis on ozone formation potentials (OFPs) indicated that toluene was the most important species in ozone production with the accountabilities for total OFPs of 22.6 to 59.6 %.     

树脂吸附-Fenton 试剂氧化法预处理炼油碱渣废水

采用树脂吸附-Fenton 试剂氧化组合工艺对某炼油企业炼油碱渣废水进行预处理.实验确定的最佳工艺条件为:3 种树脂串联吸附,废水流量0.33 mL/ min,H2O2加入量0.20 mol / L,n（H2O2）1 n（Fe2 +）= 12,Fenton 试剂氧化进水pH 3,Fenton 试剂氧化反应时间120 m...     

气象因子对臭氧的影响及其在空气质量预报中的应用

为提高重庆市臭氧(O_3)预报准确率,利用2013—2015年5—10月O_3监测数据和气象数据,通过主成分分析、逐步回归分析等方法,确定了影响重庆O_3浓度的主要气象因素为最高温度、温差、太阳辐射、降水量、相对湿度、水气压和压差;通过基于O_3污染水平相似的主要气象控制因子筛选和最优组合的预报结果优化方法,提高了O_3预报准确率,使2016年5—8月O_3的AQI类别预报准确率由57.7%增至72.4%,O_3超标的预报准确率由38%增至46%。     

水平潜流人工湿地在不同水力负荷下的水力效率及可视化分析

构建水平潜流人工湿地装置,通过NaCl示踪脉冲实验,得到不同水力负荷条件下的水力停留时间分布密度曲线,根据不同停留时间的关系计算相对水力效率,并利用染料,进行不同水力负荷下的可视化示踪实验,通过MATLAB处理得到高对比度的流态图像。观察"死区"分布,计算"死区"相对面积用以表征其水力效率。结果表明,湿地装置进水水力负荷较高或较低时,水力效率均较低,且水力负荷较大时更明显;水力分布散度(σ2θ)的大小会对水平潜流人工湿地水力效率造成较大影响;在不同水力负荷下,采用水力学效能(λ)所得到的排序结果相比短路值(s)和有效体积比(e)更能代表实际水平潜流人工湿地的水力效率。     

Quantitative analysis of CO2 embodiment in international trade: An overview of emerging literatures

The increasing volume of CO₂ embodiment in international trade adds a layer of complexity to environmental policies and has raised arguments on the traditional production based responsibility for CO₂ emissions. In order to help understand the quantity of CO₂ embodiment in trade and its policy implications, this paper gives observations to recently emerging literatures that quantitatively discuss CO₂ embodiment in trade. The analytical approaches share the principle of using input and output modeling but vary dramatically in study boundary and estimation accuracy. The calculations can be roughly categorized into three types: direct quantification of CO₂ embodiments in multiregional trade, direct quantification of CO₂ embodiment in bilateral trade, and indirect analysis by comparing the scenarios with or without trade. The practical estimations strongly rely on trade partner selection and data availability. An obvious imbalance of net CO₂ embodiment in the commodity trade between major developed countries and developing economies as a whole was confirmed by these literatures. Carbon taxes and other possible limitations on CO₂ emissions have been addressed. The consistency across the calculations could be enhanced by systematic analyses in more detail to convince the international community to take binding commitments for the reduction of global CO₂ emissions.     

In vitro activity of antimicrobial agents against Legionella isolated from environmental water systems: first results from Turkey

We evaluated the in vitro activity of antimicrobial agents against Legionella obtained from hotel and hospital water systems in three different regions of Turkey. Sixty-five Legionella strains (Legionella pneumophila serogroup 6 [n?=?32], L. pneumophila serogroup 1 [n?=?27], L. pneumophila serogroup 3 [n?=?2], and Legionella spp. [n?=?4]) were tested against levofloxacin, ciprofloxacin, clarithromycin, azithromycin, and rifampicin. The minimum inhibitory concentration (MIC) values of each antimicrobial agent for these strains was determined by the microdilution method using buffered yeast extract medium supplemented with 0.1% ketoglutarate broth. L. pneumophila ATCC 33152, Staphylococcus aureus ATCC 29213, and Escherichia coli ATCC 25922 were used as controls. Minimum inhibitory concentration values were in the following ranges: clarithromycin 0.001–0.5 mg/L, azithromycin 0.001–0.5 mg/L, levofloxacin 0.001–0.5 mg/L, ciprofloxacin 0.001–0.125 mg/L, and rifampicin 0.001– 0.5 mg/L. The MIC₉₀ for rifampicin, levofloxacin, ciprofloxacin, azithromycin, and clarithromycin were 0.015, 0.125, 0.06, 0.125, and 0.06 mg/L, respectively. To the best of our knowledge, this is the first study to determine in vitro activities of antimicrobial agents against Legionella species in Turkey. Rifampicin had the lowest MIC₉₀ value. It would seem that azithromycin and clarithromycin exhibit good activity as well as levofloxacin and ciprofloxacin against Legionella isolated from environmental water systems in Turkey.     

Al3+胁迫对茶园土壤微生物区系及生理群的影响

以茶园土壤为研究对象,通过外源添加Al3+溶液,研究了Al3+胁迫对茶园土壤微生物区系及生理群的影响.结果表明,茶园土壤中的不同种类的微生物对Al3+的敏感性不同,Al3+添加量升至0.8 g/kg时,放线菌、真菌有一定的耐受性,而细菌数量呈快速下降趋势,亚硝化细菌几乎不能成活,但随着Al3+添加量的进一步升高,放线菌...     

Evaluation of airborne particulate matter and metals data in personal,indoor and outdoor environments using ED-XRF and ICP-MS and co-located duplicate samples

Factors and sources affecting measurement uncertainty associated with monitoring metals in airborne particulate matter (PM) were investigated as part of the Windsor, Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate samples and a comparison of two analytical approaches: ED-XRF and ICP-MS. Sampling variability was estimated using relative percent difference (RPD) of co-located duplicate samples. The comparison of ICP-MS and ED-XRF results yields very good correlations (R² ≥ 0.7) for elements present at concentrations that pass both ICP-MS and ED-XRF detection limits (e.g. Fe, Mn, Zn, Pb and Cu). PM concentration ranges (median, sample number) of 24-h indoor PM₁₀ and personal PM₁₀ filters, and outdoor PM_2.5 filters were determined to be 2.2–40.7 (11.0, n = 48) μg m^?3, 8.0–48.3 (11.9, n = 48) μg m^?3, and 17.1–42.3 (21.6, n = 18) μg m^?3, respectively. The gravimetric analytical results reveal that the variations in PM mass measurements for same-day sampling are insignificant compared to temporal or spatial variations: 92%, 100% and 96% of indoor, outdoor and personal duplicate samples, respectively, pass the quality criteria (RPD ≤ 20%). Uncertainties associated with ED-XRF elemental measurements of S, Ca, Mn, Fe and Zn for 24-h filter samples are low: 78%–100% of the duplicate samples passed the quality criteria. In the case of 24-h filter samples using ICP-MS, more elements passed the quality criteria due to the lower detection limits. These were: Li, Na, K, Ca, Si, Al, V, Fe, Mn, Co, Cu, Mo, Ag, Zn, Pb, As, Mg, Sb, Sn, Sr, Th, Ti, Tl, and U. Low air concentrations of metals (near or below instrumental detection limits) and/or inadvertent introduction of metal contamination are the main causes for excluding elements based on the pass/fail criteria. Uncertainty associated with elemental measurements must be assessed on an element-by-element basis.     

活性碳纤维改性技术研究进展

介绍了活性碳纤维(ACF)的孔结构及表面官能团,综述了国内外ACF改性技术的研究现状.ACF的改性主要包括孔结构调控和表面化学改性,表面化学改性包括氧化还原法、表面负载法、浸渍法、热处理法、远程等离子体处理法、微波辐照法等,也可将多种方法结合来对ACF进行改性,以改善和提高ACF的吸附性能.在总结现有研究的基础上,对ACF改性技术发展趋势进行了展望.     

重金属元素在冻土与融土中迁移的对比试验

随着寒区经济的发展,冻土地区的矿山开采活动不断加剧,随之产生的重金属污染问题也越来越严重.冻土地区生态环境脆弱,一旦受到破坏就很难恢复.针对此问题,室内模拟了尾矿矿渣在冻土与融土中的填埋及其对填埋场周边土体的影响,通过检测填埋场各处土壤的温度、含水量以及重金属元素的含量,发现温度和水分对重金属元素的迁移影响很大.土壤温度越低,重金属元素的迁移越慢;在温度梯度的作用下,重金属元素均随着水分从土体的暖端向冷端迁徙并聚集于冻结锋面.重金属元素在冻土中的迁移比融土中慢,表明冻土环境不利于重金属元素的迁移.在土壤质地、温度和含水量等相同的情况下,Zn的迁移性较强,Pb和Cu的迁移性相对较弱.