大气硝酸测量方法研究进展

大气中硝酸(HNO3)的生成是排放到空气中氮氧化物(NOx)的主要沉降途径,对降水酸化、二次细颗粒物中硝酸盐的形成以及在研究光化学污染和霾形成等大气复合污染过程之间的联系中具有重要作用.获得高时间分辨率、准确的大气HNO3测量数据对研究和认识大气中NOx的循环机理是十分必要和迫切的.大气中的HNO3浓度低且具有很强的吸...     

Seasonal variation in surface ozone and its regional characteristics at global atmosphere watch stations in China

We investigated the seasonal and spatial ozone variations in China by using three-year surface ozone observation data from the six Chinese Global Atmosphere Watch(GAW)stations and tropospheric column ozone data from satellite retrieval over the period2010–2012. It is shown that the seasonal ozone variations at these GAW stations are rather different, particularly between the western and eastern locations. Compared with western China, eastern China has lower background ozone levels. However, the Asian summer monsoon(ASM) can transport photochemical pollutants from the southern to the northern areas in eastern China, leading to a northward gradual enhancement of background ozone levels at the eastern GAW stations. Over China, the tropospheric column ozone densities peak during spring and summer in the areas that are directly and/or indirectly affected by the ASM, and the peak time lags from the south to the north in eastern China. We also investigated the regional representativeness of seasonal variations of ozone at the six Chinese GAW stations using the yearly maximum tropospheric column month as indicator.The results show that the seasonal variation characteristics of ozone revealed by the Chinese GAW stations are typical, with each station having a considerable large surrounding area with the ozone maximum occurring at the same month. Ozone variations at the GAW stations are influenced by many complex factors and their regional representativeness needs to be investigated further in a broader sense.     

Ecotoxicity of silver nanoparticles on earthworm Eisenia fetida: responses of the antioxidant system,acid phosphatase and ATPase

Ecotoxicity of nanoparticles has received growing attention in recent years. This study investigated the influence of silver nanoparticles (Ag-NP) on earthworm Eisenia fetida. The experiment was performed with five test groups: control (without Ag-NP), 10?nm Ag-NP groups (20, 100 or 500?mg?kg^?1) and positive control (787?mg?kg^?1 AgNO₃). After 14-day acute exposure, activities of various enzymes, including glutathione S-transferase (GST), glutathione reductase (GR), acid phosphatase (AP), and Na⁺, K⁺-ATPase were determined. Effects of Ag-NP with different sizes (10 and 80?nm) were also tested. Data showed that the activity of GR was significantly lower at 500?mg?kg^?1. The activities of AP and Na⁺, K⁺-ATPase were inhibited following the increase of Ag-NP concentration. When treated with Ag-NP with different sizes, activities of AP and Na⁺, K⁺-ATPase of the 10?nm group were significantly lower than the control group, but those of the 80?nm group were similar to the control group. Data indicate that Ag-NP may be harmful to the earthworm E. fetida at 500?mg?kg^?1, and the toxicity of Ag-NP with 10?nm size is greater than 80?nm. In addition, AP and Na⁺, K⁺-ATPase are sensitive biomakers to the effects of Ag-NP.     

红外气体分析仪比对防护试验检测方法的探究

本文通过比对检测方法,即化学法检测氨气防护试验的浓度和仪器法进行比对试验,得出两种方法准确度为2.77%,一致性良好,并且红外气体分析仪自动化程度高,测定简便、迅速,适用于防护试验。     

北京城区大气苯系物变化特征及其环境意义

使用在线分析仪于2018年7月至2019年2月在北京城区对大气中的苯系物(BTEX)进行连续监测.监测期间BTEX平均体积分数为(5.05±5.23)×10-9,其中苯、甲苯、乙苯、间/对二甲苯及邻二甲苯的体积分数分别为(1.51±1.70)×10-9、(2.22±2.05)×10-9、(0.38±0.46)×10-9...     

我国典型城市中小学水环境教育现状与需求解析

本文选择青岛、武汉两城市为代表,对我国典型城市中小学水环境教育现状进行了调查研究,研究结果表明,目前已经在两地已开展的环境教育活动对青少年环境知识水平的提高起到了积极作用.但是,青少年环境保护意识仍需加强,相关知识有待于和实践进一步结合,同时在解决环境问题的技能、思考力和判断力方面仍有很大的空间.因此,构建我国青少年水环境教育体系应进一步注重提高青少年解决环境问题的思考力和环境意识,特别是落实到水环境保护行为的教育需纳入青少年环境教育框架.     

四氯化碳在包气带的迁移机理及动态降解

生物降解方法是处理有机物污染的土壤和地下水的主要途径。试验以污染场地土壤为样本,分析土样的有机碳含量、容重、密度、孔隙比、饱和含水率等基本物理特性,并制作成试验土柱,模拟研究四氯化碳在包气带土壤中垂直迁移规律,动态分析影响生物降解的主要因素。结果表明,四氯化碳随淋溶作用向深层迁移,并在包气带底部积聚;温度是影响生物降解的重要因素,当温度为18℃时,稳定降解率最大为48.2μg/L;该菌株最适宜降解的四氯化碳淋溶强度为42.3μg/L,此时菌株能正常地进行生物代谢;25 g/L的葡萄糖对微生物降解有促进作用,稳定降解率达44.3%。     

基于信息扩散理论的江苏省酸雨风险评估

利用江苏省2008-2013年24个站的酸雨监测资料,分析出2008-2013年江苏省酸雨的强度和发生频率都有下降趋势,秋冬季酸雨发生频率高,夏季最低。基于信息扩散理论对全省酸雨进行风险评估,结果发现:年降水p H值和酸雨发生频率在不同风险水平分布特征较为一致,呈西北-东南逐渐增强趋势;年降水p H值80%的可能介于4.5~5.6之间,呈弱酸性;淮河以南地区酸雨发生频率的风险为40%的概率超过90%。     

铁掺杂介孔氧化硅-石墨化炭复合物对橙黄Ⅱ的吸附

利用水热法合成铁掺杂介孔氧化硅-石墨化炭复合物(Fe MS),并对其进行结构表征,发现其具有介孔结构,且高铁含量的Fe MS含有明显的石墨化炭物种.比较了传统吸附剂活性炭、SBA-15及Fe MS分别对橙黄Ⅱ的吸附性能,考察了初始p H、投加量、初始浓度、吸附时间对吸附的影响,并对吸附过程进行了动力学研究和吸附等温模型的模拟.结果表明:Fe MS对橙黄Ⅱ有很好的吸附性能,且高铁含量的Fe MS吸附量优于低铁含量;Fe MS吸附橙黄Ⅱ的最佳p H值为7,最高吸附量能达到1108 mg·g-1;初始浓度对橙黄Ⅱ吸附效率有明显的影响;对低浓度的橙黄Ⅱ,可在120 min内达到吸附平衡;Fe MS对橙黄Ⅱ的吸附动力学数据符合准二级动力学模型;Fe MS对低浓度橙黄Ⅱ的吸附符合Henry等温模型,饱和吸附量与橙黄Ⅱ的浓度有关.     

硫化氢浓度测定方法的比较和建议

本文研究了过滤式防毒面具滤毒罐防护硫化氢性能试验中,采用用碘量法和紫外光度法对硫化氢浓度测定的对比。通过试验证明了,碘量法测得的硫化氢的浓度均偏低。结果表明:紫外光度法具有良好的准确度和精确度,适用于长时间测定硫化氢混合气体浓度。