Secondary organic carbon quantification and source apportionment of PM10 in Kaifeng, China

During 2005, the filter samples of ambient PM₁₀ from five sites and the source samples of particulate matter were collected in Kaifeng, Henan Province of China. Nineteen elements, water-soluble ions, total carbon (TC) and organic carbon (OC) contained in samples were analyzed. Seven contributive source types were identified and their contributions to ambient PM₁₀ were estimated by chemical mass balance (CMB) receptor model. Weak associations between the concentrations of organic carbon and element carbon (EC) were observed during the sampling periods, indicating that there was secondary organic aerosol pollution in the urban atmosphere. An indirect method of “OC/EC minimum ratio” was applied to estimate the concentration of secondary organic carbon (SOC). The results showed that SOC contributed 26.2%, 32.4% and 18.0% of TC in spring, summer-fall and winter, respectively, and the annual average SOC concentration was 7.07 μg/m³, accounting for 5.73% of the total mass in ambient PM₁₀. The carbon species concentrations in ambient PM₁₀ were recalculated by subtracting SOC concentrations from measured concentrations of TC and OC to increase the compatibility of source and receptor measurements for CMB model.     

水泥行业SO2和NOX排放总量核算方法选取

就水泥企业SO₂和NO_X排放总量核算方法的选取问题,以3家不同类型水泥企业为例,以监测数据法核算结果为依据,对排污系数法和物料衡算法的核算结果进行统计学描述和差异性检验。结果表明:排污系数法能基本反映各类企业SO₂、NO_X实际排放状况;物料衡算法不适合各类企业NO_χ的总量核算;对含熟料生产线的水泥企业,物料衡算法核算得出的SO₂排放量偏小,实际工作中不建议采用;对粉磨站水泥企业,物料衡算法与排污系数法均能反映实际SO₂排放情况,建议以"取大值"原则选取。     

Environmental impacts of irrigated sugarcane production: Nitrogen lost through runoff and leaching

There is concern about environmental impacts of cropping in catchments of Australia's Great Barrier Reef, especially losses of nitrogen (N) from cropping systems. Sugarcane production in the Burdekin region in the dry tropics stands out from other crops/regions because it is grown with the highest applications of irrigation water and N fertiliser rates of any sugarcane producing region in Australia, attributes which may enhance losses of N. Little is known about N losses from sugarcane production systems, especially irrigated systems. We measured parts of the water and N balance over three sugarcane crops at three contrasting sites in different parts of the Burdekin region, covering a range of soil types/textures and irrigation managements. The experimental data were used to parameterise the APSIM-Sugarcane cropping systems model, and the model then used to ‘infill’ missing data and develop more complete water and N balances for each of the crops at the three sites. The model was also used to simulate long-term yields and N losses through runoff and leaching below the root zone at the sites under a range of N fertiliser and irrigation management practices. Unlike the experience in other cropping systems, N losses through runoff and leaching below the root zone were not higher at our sites than measured in rainfed sugarcane production systems. The long-term simulations showed there were clear opportunities for reducing N losses while maintaining yields through reducing N fertiliser application rates. Simulations results suggested that long-term N surpluses of 50 kg ha⁻¹ yr⁻¹, considerably less than those during the experiment or common in the study region, were sufficient to maintain yields but reduce N losses by 50-57%. So, N fertiliser management should aim to keep surpluses to that level. Improved irrigation management could also help reduce N losses but generally to a much lesser extent than reduced N fertiliser applications. Research is required to confirm these predicted benefits, and investigate potential interaction between N fertiliser and irrigation management practices, and impacts of other management practices.     

基于污染物平衡分析的污水厂尾水补水城市内湖的优化运行研究——以昆明翠湖为例

针对污水厂尾水补水的城市内湖污染调控问题,提出了基于水量和污染物收支平衡分析的污染物净积累(NPA)模型,建立了污染物输入和输出量化计算方法.最后,以昆明翠湖为案例,在调查水体污染物输入和输出途径及水体自净量计算的基础上,选择COD、TN和TP为代表性污染物,开展了模型和计算方法的应用.结果表明,尾水补水是污染物输入的最主要途径,排水和渗漏是污染物输出的两个主要途径,COD在水体中的净积累程度较低,TN和TP的净积累比例分别达到42.9%和39.0%.以此为基础,本文提出了以调整补水和用水途径为主要手段的水体优化运行方案,并对方案实施后的预期效果进行了分析验证.本研究可为城市景观水体的污染物积累分析提供新方法和典型案例.     

The Mass and Energy Exchange of a Tibetan Glacier: Distributed Modeling and Climate Sensitivity

Most glaciers in the Tibetan Plateau (TP) are not closely monitored for mass balance (MB) due to their inaccessibility, which makes it difficult to better understand the dynamics of glacial advancement or retreat. Surface energy budget, MB, and the resulting melt runoff were calculated for Zhadang glacier (5,710 m above sea level) of the central TP. Energy balance was calculated on 30‐m square grids for the summers of 2007 and 2008. On average, net radiation dominated the total energy source (66%) while the residual was supplied by sensible heat flux. More than 67% of the energy sink was available for melting on the glacier. Thus, less than 33% of the total energy was consumed by latent heat flux. A large and a slightly negative summer MB were calculated for the 2007 and 2008 summers, respectively. The high sensitivity of the glacier to air temperature may indicate that the lower than average seasonal temperature was more important than the increased precipitation for the slightly negative MB in the summer of 2008. Comparisons of glacial melt runoff indicated that rainfall and snowmelt were the dominant contribution to total runoff in the glacierized basin and the ice melting is also very important. Glacial melt calculation provides a basis for quantifying glacial melt‐runoff contribution to the river streamflow in the TP.     

庭院垃圾对填埋场甲烷的减量化研究

将熟化时间为24个月和2个月的庭院垃圾分别用于建设0.9 m厚的1#和2#两个生物覆盖层单元,并进行了为期15个月的野外试验,以验证庭院垃圾能否作为生物覆盖层材料用于减少垃圾填埋场甲烷的排放,以及利用同位素和质量守恒方法量化生物覆盖层对垃圾填埋场甲烷的氧化能力.结果表明,两个生物覆盖层对甲烷的氧化能力在建设初期达到整个观测期的最高值,分别为(141±10)g·m-2·d-1和(197±27)g·m-2·d-1,随后生物覆盖单元的甲烷氧化能力随季节交替降低至18~120 g·m-2·d-1和23~70 g·m-2·d-1.试验的中后期,在两个生物覆盖单元中均观测到明显数量的甲烷产出.试验结果表明24个月和2个月熟化时间的庭院垃圾作为生物覆盖填料,均具有较好的甲烷减量化能力,但所含不稳定有机质在厌氧条件下的降解会造成额外的甲烷释放.除此之外,在利用质量守恒方法量化甲烷氧化率时,忽略非甲烷氧化菌的呼吸作用会高估庭院垃圾对甲烷的减量化能力.     

海口市PM_(2.5)和PM_(10)来源解析

以海口市为例,研究了我国典型热带沿海城市——海口市环境空气颗粒物的污染特征和主要来源.2012年春季和冬季在海口市区4个采样点同步采集了环境空气中PM10和PM2.5样品,同时采集了多种颗粒物源样品,并使用多种仪器分析方法分析了源与受体样品的化学组成,建立了源化学成分谱.使用CMB(化学质量平衡)模型对海口市大气颗粒物进行源解析.结果表明:污染源贡献具有明显的季节特点,并存在一定的空间变化.冬季城市扬尘、机动车尾气尘、二次硫酸盐和煤烟尘是海口市PM10和PM2.5中贡献较大的源,在PM10和PM2.5中贡献率分别为23.6%、16.7%,17.5%、29.8%,13.3%、15.7%和13.0%、15.3%;春季机动车尾气尘、城市扬尘、建筑水泥尘和二次硫酸盐是海口市PM10和PM2.5中贡献较大的源,在PM10和PM2.5中贡献率分别为27.5%、35.0%,20.2%、14.9%,12.8%、6.0%和9.5%、10.5%.冬季较重的颗粒物污染可能来自于华南内陆地区的区域输送,特别是,本地排放极少的煤烟尘和二次硫酸盐受区域输送的影响更为显著.     

Process hazard assessment of energetic ionic liquid with kinetic evaluation and thermal equilibrium

With the continuous development of battery technology, there are new research investments in materials of various parts. In the field of electrolytes, ionic liquids (IL) are considered to be excellent electrolytes and have been widely studied in distinct energy fields. However, it is necessary to pay attention to the safety characteristics of ionic liquids at high temperature due to the application of energy, but there is little research on the reaction and kinetics of ionic liquids. To ensure the safety of ionic liquids, such as high temperature, the common ionic liquid 1-Ethyl-3-methylimidazolium nitrate ([Emim] NO₃) was selected for analysis. The exothermic mode is obtained from the data of differential scanning calorimetry. The basic reaction parameters of [Emim] NO₃ were determined with thermodynamic equation simulation. For ionic liquids in the actual situation, consider adding a heat balance model to estimate its temperature change pattern and find out the hazard temperature and related safety parameters. Temperature changes were estimated by constructing 25.0 g and 50.0 g packages to simulate material reactions and heat transfer in the external environment. The results showed that [Emim] NO₃ had shorter TMR_ad and TCL (<1 day) when the temperature was above 180 °C.     

1959-2008年乌鲁木齐河源1号冰川融水径流变化及其原因

采用数理统计、 Morlet小波分析和Mann-Kendall突变检验对乌鲁木齐河源1号冰川1959-2008年径流序列进行分析,揭示了冰川融水径流的变化趋势、 周期特征和突变特性,并对径流与气候、 冰川变化关系进行了探讨。结果表明:乌鲁木齐河源1号冰川近50 a来径流增加趋势显著,特别是在1993年发生突变后,平均径流较1993年前增加了69.4%。径流序列第一主周期为15 a,第二主周期为6 a。在13~16 a时间尺度上看,1号冰川融水径流在未来的几年将继续保持偏多趋势,但是从5~7 a和超长期时间尺度上看则相反。冰川融水径流与冰川物质平衡、 年均气温、 消融期气温及年降水量存在良好的瞬时响应关系,其中消融期气温的振动对冰川融水径流振动能量贡献最大,在气温超过2 ℃时,径流将加速增长。物质平衡变化100 mm可引起河流径流变化22.9×10⁴ m³,1号冰川过去50 a累积物质平衡为-13 693 mm,相当于额外补给河流径流量3 135.7×10⁴ m³,约是年径流量的16.1倍。     

Conversion characteristics and mechanism analysis of gaseous dichloromethane degraded by a VUV light in different reaction media

The photodegradation of gaseous dichloromethane (DCM) by a vacuum ultraviolet (VUV) light in a spiral reactor was investigated with different reaction media and initial concentrations. Through the combination of direct photolysis, O₃ oxidation and HO. oxidation, DCM was ultimately mineralized into inorganic compounds (such as HCl, CO₂, H₂O, etc.) in the air with relative humidity (RH) of 75%-85%. During the photodegradation process, some small organic acids (including formic acid, acetic acid) were also detected and the intermediates were more soluble than DCM, providing a possibility for its combination with subsequent biodegradation. Based on the detected intermediates and the confirmed radicals, a photodegradation pathway of DCM by VUV was proposed. With RH 75%-80% air as the reaction medium, the DCM removal followed the second-order kinetic model at inlet concentration of 100-1000 mg/m³. Kinetic analysis showed that the reaction media affected the kinetic constants of DCM conversion by a large extent, and RH 80% air could cause a much lower half-life for its conversion. Such results supported the possibility that VUV photodegradation could be used not only for the mineralization of DCM but also as a pretreatment before biodegradation.