Regulated emission characteristics of in-use LNG and diesel semi-trailer towing vehicles under real driving conditions using PEMS

On-road driving emissions of six liquefied natural gas(LNG) and diesel semi-trailer towing vehicles(STTVs) which met China Emission Standard IV and V were tested using Portable Emission Measurement System(PEMS) in northern China.Emission characteristics of these vehicles under real driving conditions were analyzed and proved that on-road emissions of heavy-duty vehicles(HDVs) were underestimated in the past.There were large differences among LNG and diesel vehicles, which also existed between China V vehicles and China IV vehicles.Emission factors showed the highest level under real driving conditions, which probably be caused by frequent acceleration, deceleration, and start-stop.NOx emission factors ranged from 2.855 to 20.939 g/km based on distance-traveled and 6.719–90.557 g/kg based on fuel consumption during whole tests, which were much higher than previous researches on chassis dynamometer.It was inferred from tests that the fuel consumption rate of the test vehicles had a strong correlation with NOx emission, and the exhaust temperature also affected the efficiency of Selected Catalytic Reduction(SCR) aftertreatment system, thus changing the NOx emission greatly.THC emission factors of LNG vehicles were 2.012–10.636 g/km, which were much higher than that of diesel vehicles(0.029–0.185 g/km).Unburned CH_4 may be an important reason for this phenomenon.Further on-road emission tests, especially CH_4 emission test should be carried out in subsequent research.In addition, the Particulate Number(PN) emission factors of diesel vehicles were at a very high level during whole tests, and Diesel Particulate Filter(DPF)should be installed to reduce PN emission.     

便携式GC-MS法快速测定固定污染源废气中的VOCs

采用便携式GC-MS法快速测定固定污染源废气中VOCs,32种VOCs在2×10~(-7)~1×10~(-6)范围内线性良好,方法检出限为2×10~(-9)~1×10~(-8),标准气体样品6次测定结果的RSD为1.9%~19.1%,环境空气样品的加标回收率为66.2%~116%。在实际现场监测固定污染源中VOCs时,使用速查(Survey)功能可初步判断样品浓度,确定稀释倍数。比对试验结果表明,气袋和玻璃注射器采样法对VOCs测定结果无显著性差异。     

便携式GC/MS热脱附法直接测定环境空气中挥发性有机物

采用便携式气相色谱/质谱联用热脱附法直接测定环境空气中的挥发性有机物,优化了试验条件。方法在5×10-9~100×10-9范围内线性良好,39种化合物的检出限为1.1μg/m3~19μg/m3,标准气体平行测定的RSD≤11.0%,回收率在80%~120%之间。     

Rapid detection of toxic metals in non-crushed oyster shells by portable X-ray fluorescence spectrometry

The aim of this study was the multi-elemental detection of toxic metals such as lead (Pb) in non-crushed oyster shells by using a portable X-ray fluorescence (XRF) spectrometer. A rapid, simultaneous multi-element analytical methodology for non-crushed oyster shells has been developed using a portable XRF which provides a quick, quantitative, non-destructive, and cost-effective mean for assessment of oyster shell contamination from Pb. Pb contamination in oyster shells was further confirmed by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS). The results indicated that Pb is distributed in-homogeneously in contaminated shells. Oyster shells have a lamellar structure that could contribute to the high accumulation of Pb on oyster shells.     

便携式GC-MS仪快速测定水中硝基苯及其在应急监测中的应用

采用便携式GC-MS仪快速测定水中硝基苯,通过优化水中离子强度和顶空加热时间,使方法在0μg/L^300μg/L范围内线性良好,方法检出限为2.5μg/L。标准溶液6次测定结果的RSD为7.8%~10.9%,实际水样的加标回收率为80.7%~103%。同步测定试验表明,硝基苯与7种苯系物分离良好。与国标方法对比,该方法单个样品测定时间由2 h缩短为15 min。将该方法用于应急监测工作中,及时有效的数据可为污水处理及事故调查提供分析和研判依据。     

环境污染物快速检测技术的国内外研究进展

介绍了环境污染物的分类与危害,基于目前国内外不同类型污染物快速检测技术的研究进展,综述了包括离子传感器、气体传感器和生物传感器等在内的化学传感器选择性强、成本低廉、可检测痕量污染物的优势,以及便携式检测设备节省时间、避免样品采集、应用领域广泛的特点,并提出了污染物快速检测技术的未来发展方向。     

野外便携净水器净水消毒工艺试验研究

野外便携净水器应具杀菌消毒效率高、净水时间短、使用寿命长、操作方便等功能使用要求。通过试验考察了三碘树脂和载银活性炭两种不同净水消毒工艺流程对原水处理效果。结果表明：三碘树脂材料比载银活性炭材料具有灭菌效果好、反应接触时间短、使用时间长等优势，是一类具有良好军事应用价值的野外便携净水器的净水消毒材料。     

便携式布氏硬度计在电厂金属硬度检测中的应用

针对电厂金属部件及焊缝现场硬度检测中里氏硬度计误差较大的问题,介绍了有关标准的进展情况,以及便携式布氏硬度计和压痕自动测量装置的最新技术.结果表明:在现场硬度检测中,对有争议的硬度值宜采用便携式布氏硬度计进行测量校核,国内已形成关于便携式布氏硬度计的标准体系,自动压痕测量装置配合便携式布氏硬度计非常适于电厂的现场硬度检测,通过换算得到的数据,不能作为投诉和满足验收要求的依据.     

Identification and mapping of heavy metal pollution in soils of a sports ground in Galway City,Ireland, using a portable XRF analyser and GIS

Heavy metals in urban soils continue to attract attention because of their potential long-term effects on human health. During a previous investigation of urban soils in Galway City, Ireland, a pollution hotspot of Pb, Cu, Zn and As was identified in the sports ground of South Park in the Claddagh. The sports ground was formerly a rubbish dumping site for both municipal and industrial wastes. In the present study, a portable X-ray fluorescence (PXRF) analyser was used to obtain rapid in-situ elemental analyses of the topsoil (depth: about 5–10 cm) at 200 locations on a 20 × 20-m grid in South Park. Extremely high values of the pollutants were found, with maximum values of Pb, Zn, Cu and As of 10,297, 24,716, 2224 and 744 mg/kg soil, respectively. High values occur particularly where the topsoil cover is thin, whereas lower values were found in areas where imported topsoil covers the polluted substrate. Geographic Information Systems (GIS) techniques were applied to the dataset to create elemental spatial distribution maps, three-dimensional images and interpretive hazard maps of the pollutants in the study area. Immediate action to remediate the contaminated topsoil is recommended to safeguard the health of children who play at the sports ground.     

便携式GC法测定石油污染地地下水中苯、乙苯和二甲苯

采用便携式气相色谱法测定石油污染地地下水中苯、乙苯和二甲苯，通过试验选择出测定的最佳色谱条件和适宜内标物，并对样品平衡时间、NaCl用量、取样后 VOA瓶中液-气体积比等条件进行优化。试验表明，该方法在0 mg/L～2．00 mg/L范围内线性良好，相关系数均＞0．98；方法检出限为0．05 mg/L ～0．15 mg/L。用该方法和吹扫捕集-气相色谱/质谱联用法同时测定实际水样，两种方法测定结果具有良好的一致性。