北京市石景山区PM2.5中典型水溶性离子分布特征及其致敏效应研究

为了考察大气细颗粒物水溶性成分与过敏性疾病的相关性,对北京市石景山区PM_2.5中水溶性离子分布特征进行分析,对文献中报道的有机酸浓度进行总结,选取其中9种典型水溶性无机盐（硝酸铵、硫酸铵、氯化铵、硝酸钠、无水硫酸钠、硝酸钾、硫酸钾、硝酸钙、硫酸钙）及3种水溶性有机酸（丙二酸、丁二酸、乙二酸）进行肥大细胞激活实验,观察上述成分经IgE及非IgE途径对肥大细胞β-Hex释放率的影响.结果表明：铵离子、硝酸离子和硫酸离子是研究区PM_2.5中占比最大的3种离子,丙二酸、丁二酸、乙二酸是北京市PM_2.5中3种浓度较高的水溶性有机酸.非IgE途径下,100μg·mL^-1的9种水溶性无机盐和80μg·mL⁽-1(的3种水溶性有机酸均无法提高肥大细胞β-Hex释放率.IgE途径下,仅观察到80μg·mL^-1丙二酸能使肥大细胞β-Hex释放率提高约3%,其增敏作用还需进一步研究证实.本研究将为进一步研究PM_2.5水溶性成分诱发或加重过敏性疾病的潜在机制...     

区域氮干沉降分布特征的数值模拟

氮沉降对全球尺度的粮食生产、碳氮循环及大气环境质量均具有重要影响.本研究采用WRF-Chem模式对区域氮沉降过程进行数值 模拟,着重分析氮干沉降的时空分布特征.结果表明：在空间场上,我国氮干沉降主要体现出东高西低的特点,华北平原和川渝地区为氮沉降高值区,这主要与排放高值区的空间分布有关,NH₃和HNO₃ 沉降量都是在东部最大,这与东部一直以来较高的经济增长速度和农业活动水平有直接联系.从氮的不同组分形式（气态/颗粒态氮或者氧化性/还原性氮）来看,气态氮较颗粒态氮对总氮沉降的贡献更大,贡献比达66%; 相较氧化性氮,还原性氮对总氮沉降的贡献较大,贡献比为57%.进一步分析不同下垫面类型的氮干沉降结果,气态氮的干沉降均是在城市和农田下垫面上更高.NH₃ 干沉降通量主要受排放源影响,HNO₃ 干沉降通量则受气象条件影响较大,而排放源和气象条件均有很强的季节性 变化.NH₄⁺和NO₃^-在森林下垫面上的干沉降通量远多于其它类型的下垫面,这主要是因为森林下垫面粗糙度比较大,相应的摩擦速度也较大,湍流比较活跃,有利于粒子污染物的沉积.     

基于栅格尺度的生态安全评价及生态修复——以酒泉市肃州区为例

以节约优先、保护优先和自然恢复的方针为导向,基于栅格尺度评价生态安全状态,并开展国土空间生态修复分区,有助于实施精准修复、降低生态修复成本以及增加生态修复效益。本文以酒泉市肃州区为例,从环境基底和人类干扰的视角遴选评价因子,采用空间主成分分析法（SPCA）基于栅格尺度对生态安全进行评价,并将宏观尺度的生态保护红线和永久基本农田保护等现实约束条件与栅格尺度的生态安全评价结果相结合,实现精准的生态修复分区。结果表明：研究区整体生态安全水平偏低,中度安全水平及以下的面积为1391.65 km²,占研究区总面积的71.35%,生态安全格局总体呈中部高、四周低的特征。肃州区国土空间生态修复分区共划分出5个类型区,其中生态恢复区面积最大,占研究区总面积的46.17%。生态控制、生态保育、生态提升和生态整治四个类型区在乡村分布最多,说明肃州区乡村生态修复的复杂度、难度和重要程度更高。本文运用新的生态修复分区研究思路,以期丰富国土空间生态保护修复规划理论与方法。     

Reducing ammonia gas from chicken manure with lime and soybean plants

This research is aimed at addressing the complaints of local people living near chicken farms who are disturbed by odors caused by livestock activities, and specifically, by the generation of ammonia gas from chicken manure. Methods that are expected to reduce the intensity of ammonia gas odors include both scattering lime on the surface of the soil and planting soybeans around the cages. The results obtained showed a reduction in the levels of ammonia gas by 57.48%–from 1.67 parts per million (ppm) near an untreated cage to 0.71 ppm near the cage that achieved the best results. The study found that spreading lime evenly over the chicken manure was the most effective method that farmers could use to reduce ammonia odors. The sample area treated by the addition of soybean plants showed a reduction in the levels of ammonia gas from 1.67 to 0.78 ppm.     

Rapid discrimination of plastic packaging materials using MIR spectroscopy coupled with independent components analysis (ICA)

Plastic packaging wastes increased considerably in recent decades, raising a major and serious public concern on political, economical and environmental levels. Dealing with this kind of problems is generally done by landfilling and energy recovery. However, these two methods are becoming more and more expensive, hazardous to the public health and the environment. Therefore, recycling is gaining worldwide consideration as a solution to decrease the growing volume of plastic packaging wastes and simultaneously reduce the consumption of oil required to produce virgin resin. Nevertheless, a major shortage is encountered in recycling which is related to the sorting of plastic wastes. In this paper, a feasibility study was performed in order to test the potential of an innovative approach combining mid infrared (MIR) spectroscopy with independent components analysis (ICA), as a simple and fast approach which could achieve high separation rates. This approach (MIR-ICA) gave 100% discrimination rates in the separation of all studied plastics: polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS) and polylactide (PLA). In addition, some more specific discriminations were obtained separating plastic materials belonging to the same polymer family e.g. high density polyethylene (HDPE) from low density polyethylene (LDPE). High discrimination rates were obtained despite the heterogeneity among samples especially differences in colors, thicknesses and surface textures. The reproducibility of the proposed approach was also tested using two spectrometers with considerable differences in their sensitivities. Discrimination rates were not affected proving that the developed approach could be extrapolated to different spectrometers. MIR combined with ICA is a promising tool for plastic waste separation that can help improve performance in this field; however further technological improvements and developments are required before it can be applied at an industrial level given that all tests presented here were performed under laboratory conditions.     

石油炼化行业恶臭气体成分谱研究

为研究石油炼化行业恶臭污染排放现状,采用冷阱富集-GC/MS技术研究了天津一家典型石油炼化企业不同处理单元空气中臭气的组成、主要组分含量及成分谱.在所采集的样品中,定性分析共检测到140种有机化合物,主要包括硫化物、烷烃、烯烃、卤代烃、苯系物和含氧有机物六大类物质.定量检测结果表明,主要处理单元恶臭污染物浓度总体水平由高至低表现为气分处理装置>污油罐处理装置>汽柴油处理装置.结合数据分析,初步识别了石油炼化厂主要处理单元的特征污染物,气分处理装置有丙酮、2-丁烯、丁烷、乙硫醇、甲硫醚和甲硫醇,汽柴油处理装置有丙酮、丙烯、异丁烷、正戊烷和对二乙苯,污油罐处理装置有1-丁烯、2-丁烯、1-戊烯、丙酮、丙烯和乙硫醇.      

碳数和官能团对直链易挥发化合物异味阈值的影响规律

以具有代表性的异味特征-异味阈值为研究对象,采用三点比较式臭袋法测定了醇类、醛类、酮类、酸类和硫醇类5个系列常见异味化合物的异味阈值,研究了异味阈值与碳链长度之间的关系,并以官能团疏水性参数量化表征官能团结构,研究了异味阈值与官能团类型之间的关系.研究发现,分子碳链长度和官能团类型都能影响异味阈值的大小,其中异味阈值与碳链长度关系为y=axb或lgy=cx+d(y:异味阈值,x:碳原子数);异味阈值与官能团疏水常数π参数关系为y=aebx或lgy=cx+d(y:异味阈值,x:官能团疏水性参数).所得模型能定量描述碳链长度和官能团类型对异味阈值的影响,为异味机理的进一步探索提供了有力支撑.此外,对异味阈值与上述两因素的多元线性拟合及残差分析结果表明,碳链长度和官能团类型能够影响化合物异味阈值,但二者并非异味阈值的完全决定因素,研究决定异味阈值的全面结构因素,需大量后续工作.     

异味阈值与分子结构特征关系的研究进展

异味阈值和分子结构间的关系,受到阈值准确识别和嗅觉产生机制研究的制约,是一个非常复杂的问题.本文简要介绍了多元线性回归、拓扑指数、神经网络和分子生物学等几种研究异味阈值和分子结构关系的方法,探讨了目前存在的问题以及未来的发展趋势.     

Chemometrical analysis of waste water monitoring data from Yantra river basin,Bulgaria

A chemometrical study of waste water data is carried out in order to reveal some new information about the pollution events in Yantra river basin, Bulgaria. Cluster analysis shows that no substantial difference in the behaviour of various sites along the river could be found if all chemical pollutants are simultaneously considered as variables (both for direct and indirect inlet of pollutants). Further, the clustering of the variables indicates a separation between organic and nutrition polluting species. The principal components analysis offered information about the latent factors influencing the data structure. In principle, three to four such latent factors explain over 80% of the total variance of the system. These factors are conditionally named “organic pollution”;, “nutrition pollution”; or “natural”; and are slightly different for the cases of direct and indirect inlet.     

Development of odorous gas sampler and investigation of its practicality

The existing gas sampler is deficient in regard to its efficiency, handling and ability. In order to solve these problems, a new gas sampler was developed and its function was investigated. The sampler is a vessel made of aluminium and contains a polyester bag inside the vessel. The vacuum method is employed for taking the gas. The maximum capacity of the gas volume that can be taken is about 15 liters and sampling time can be from 15 sec to 10 min per sample. In addition, many odor surveys were carried out and the practicality of the new sampler was investigated. It was concluded that the new sampler was easy to handle and was more efficient than the existing gas sampler.