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排序方式: 共有949条查询结果,搜索用时 343 毫秒
61.
TaeSeok Oh MinJeong Kim JungJin Lim OnYu Kang K. Vidya Shetty B. SankaraRao 《Journal of the Air & Waste Management Association (1995)》2013,63(5):517-526
Subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, in this study, a new cumulative calculation method for the estimation of total amounts of indoor air pollutants emitted inside the subway station is proposed by taking cumulative amounts of indoor air pollutants based on integration concept. Minimum concentration of individual air pollutants which naturally exist in indoor space is referred as base concentration of air pollutants and can be found from the data collected. After subtracting the value of base concentration from data point of each data set of indoor air pollutant, the primary quantity of emitted air pollutant is calculated. After integration is carried out with these values, adding the base concentration to the integration quantity gives the total amount of indoor air pollutant emitted. Moreover, the values of new index for cumulative indoor air quality obtained for 1 day are calculated using the values of cumulative air quality index (CAI). Cumulative comprehensive indoor air quality index (CCIAI) is also proposed to compare the values of cumulative concentrations of indoor air pollutants. From the results, it is clear that the cumulative assessment approach of indoor air quality (IAQ) is useful for monitoring the values of total amounts of indoor air pollutants emitted, in case of exposure to indoor air pollutants for a long time. Also, the values of CCIAI are influenced more by the values of concentration of NO2, which is released due to the use of air conditioners and combustion of the fuel. The results obtained in this study confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well.
Implications: Nowadays, subway systems are considered as main public transportation facility in developed countries. Time spent by people in indoors, such as underground spaces, subway stations, and indoor buildings, has gradually increased in the recent past. Especially, operators or old persons who stay in the indoor environments more than 15 hr per day usually influenced a greater extent by indoor air pollutants. Hence, regulations on indoor air pollutants are needed to ensure good health of people. Therefore, this paper presents a new methodology for monitoring and assessing total amounts of indoor air pollutants emitted inside underground spaces and subway stations. A new methodology for the calculation of cumulative amounts of indoor air pollutants based on integration concept is proposed. The results suggest that the cumulative assessment approach of IAQ is useful for monitoring the values of total amounts of indoor air pollutants, if indoor air pollutants accumulated for a long time, especially NO2 pollutants. The results obtained here confirm that the proposed method can be applied to monitor total amounts of indoor air pollutants emitted, inside apartments and hospitals as well. 相似文献
62.
为了提高污泥水解酸化过程中的挥发酸产量,获取污水脱氮除磷所需的内碳源,以深圳市罗芳污水厂的二沉池污泥为研究对象,采用不同的碱量对其进行预处理。通过测定碱预处理污泥水解酸化过程中的挥发酸浓度,并采用聚合酶链式反应-变性梯度凝胶电泳(polymerase chain reaction denature gradient gel electrophoresis,PCR-DGGE)技术对参与碱预处理污泥水解酸化产酸过程的主要微生物种群进行分析,结果表明,当碱投加量为0.20 g NaOH/g VSS时,初始溶出的蛋白浓度为1 780 mg/L;水解酸化15 d时,挥发酸总量达到3 473 mg/L;参与产酸的主要细菌属于Firmicutes、Proteobacteria、Bacteroidetes三个门类。 相似文献
63.
Kim SS Kang YS Lee HD Kim JK Hong SC 《Journal of the Air & Waste Management Association (1995)》2012,62(2):235-241
In this study, the physicochemical properties of the char of Indonesian SM coal following heat treatment at various temperatures were evaluated using X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and morphological and specific surface area analysis. Based on these analyses, heat treatment of coal was determined to be the most effective in increasing the coal rank. In the XPS analysis, the C-O and C-O-C groups and quaternary-N species were found to be of a lower grade coal when the pretreatment temperature decreased, meanwhile the C-C group and pyridinic species increased. In the FT-IR analysis, the collapse of the C-O and C-O-C group was observed due to the collapse of the ether group. In SEM and Brunauer-Emmett-Teller (BET) analysis, a decrease in the ether group was shown to be accompanied with the formation of micropores. 相似文献
64.
65.
Cadmium tolerance in six poplar species 总被引:5,自引:1,他引:4
Jiali He Chaofeng Ma Yonglu Ma Hong Li Jingquan Kang Tongxian Liu Andrea Polle Changhui Peng Zhi-Bin Luo 《Environmental science and pollution research international》2013,20(1):163-174
Selection of poplar species with greater Cd tolerance and exploiting the physiological mechanisms involved in Cd tolerance are crucial for application of these species to phyto-remediation. The aim of this study is to investigate variation in Cd tolerance among the six poplar species and its underlying physiological mechanisms. Cuttings of six Populus species were cultivated for 10 weeks before exposure to either 0 or 200 μM CdSO4 for 20 days. Gas exchange in mature leaves was determined by a portable photosynthesis system. Cd concentrations in tissues were analyzed by a flame atomic absorbance spectrometry. Subsequently, Cd amount per plant, bio-concentration factor (BCF) and translocation factor (T f) were calculated. Nonenzymatic compounds and activities of antioxidative enzymes in tissues were analyzed spectrophotometrically. Cd exposure caused decline in photosynthesis in four poplar species including Populus cathayana (zhonghua 1). Among the six species, P. cathayana (zhonghua 1) displayed the highest Cd concentrations in tissues, the largest Cd amount in aerial parts, the highest BCF in aerial parts and T f under Cd exposure. Under Cd stress, increases in total soluble sugars in roots but decreases in starch in roots, wood, and leaves of P. cathayana (zhonghua 1) were found. Induced O 2 ?? and H2O2 production in roots and leaves, and increases in free proline, soluble phenolics, and activities of antioxidative enzymes were observed in P. cathayana (zhonghua 1). Based on results of this pot experiment, it is concluded that P. cathayana (zhonghua 1) is superior to other five species for Cd phyto-remediation, and its well-coordinated physiological changes under Cd exposure confer the great Cd tolerance of this species. 相似文献
66.
Yuan Kang Yi Yin Yubon Man Laisheng Li Qiuyun Zhang Lixuan Zeng Jiwen Luo Ming Hung Wong 《Chemosphere》2013
Human exposure to bioaccessible PCBs via indoor dust is limited around the world. In the present study, the workplace dust sample from commercial office, hospital, secondary school, shopping mall, electronic factory and manufacturing plant were collected from Hong Kong for PCBs analyses. Total PCBs concentrations ranged from 46.8 to 249 ng g−1, with a median of 107 ng g−1. Manufacturing plant showed the highest concentration among all of sampling sites. PCB 77 was found as the dominant congeners. The bioaccessibility of PCBs in small intestinal juice ranging from 8.3% to 26.0% was significantly higher than that in gastric condition, ranging from 4.8% to 12.4%. In addition, significant negative correlations (p < 0.05) were observed between KOW and bioaccessibility for all workplace dust samples. Risk assessment indicated that the averaged daily dose of dioxin-like PCBs via non-dietary intake of workplace dust, considering the bioaccessibility of PCBs, were much lower than the TDI of dioxins (2.3 pg WHO-TEQ kg bw−1 d−1) established by Joint FAO/WHO Expert Committee on Food Additives. 相似文献
67.
68.
通过把起相转移作用的聚乙二醇链固载在硅胶上(SiO2-PEG600),再将聚乙稀吡咯烷酮(PVP)络合双金属Pd-Cu(PVP-PdCl2-CuCl2)后负载其中,制成一种新型双负载双金属水相脱卤催化剂PVP-PdCl2-CuCl2/SiO2-PEG600。以甲酸钠为氢转移试制,在水相中催化有机卤化物脱卤,研究结果表明:反应温度为800℃,Pd∶Cu=2∶1(摩尔比),反应介质pH≈11.7左右时,该催化剂对芳香氯化物及α-氯代酮、酯具有良好的催化脱氯和重复使用性能。 相似文献
69.
70.
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were analyzed in agricultural soil samples from Shanghai to determine levels and to identify possible dioxin sources. The dioxin level was measured by an enzyme immunoassay method, US EPA 4025 (modified), which provides results as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents. The Method 4025m results obtained from 60 soil samples displayed a normal distribution, ranging from 2.8 to 23.4 pg/g 2378-TCDD-equvalents, with an average of 11.0 pg/g. The result also revealed a similar PCDD/Fs concentration among crop usage patterns, but differences by geographic region, low in the southwest of Shanghai and considerably higher in the northwest region. In contrast, the dioxin concentrations on Chongming Island were fairly homogeneous, with a range 10–15 pg/g. This immunoassay method is an effective high throughput screening tool which helps to minimize the need for more expensive analyses. 相似文献