Baseline soil levels of PCDD/Fs established prior to the construction of municipal solid waste incinerators in China

In order to determine the baseline contamination by polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in different areas in China, prior to the construction of municipal solid waste incinerators (MSWIs), a total of 32 representative soil samples was collected near 16 incinerators and analyzed for their PCDD/F concentrations. The PCDD/F baseline concentrations in the soil samples ranged from 0.32 to 11.4 ng I-TEQ kg⁻¹ (dry matter), with average and median value of 2.73 and 2.24 ng I-TEQ kg⁻¹ (dry matter), respectively, and a span between maximum and minimum recorded value of 36. The PCDD homologues predominated in 26 out of 32 soil samples, with the ratio (PCDDs)/(PCDFs) ranging from 1.1 to 164; however in the other 6 samples, PCDF homologues were larger, with the same ratio varying from 0.04 to 0.8. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to examine PCDD/F amount and profile in these soil samples, and their possible associations with known emission sources: in this process 6 really distinct isomer fingerprints were identified. Background PCDD/F levels and profiles were comparable to those found in soils from China and other countries and indicate a rather low baseline PCDD/F contamination of soils. The present data provide the tools for future assessment of a possible impact of these MSWIs.     

政府突发事件应急能力综合评价

应对突发事件的能力是体现政府执政水平的重要标志之一。提出应充分考虑评价对象的属性以及各评价方法的特点，可以采用层次分析法与模糊综合评价法相结合的方法对政府突发事件应急能力进行评价。运用层次分析法建立层次结构模型，确定指标权重，通过模糊综合评价法构建评价模糊矩阵，进行模糊运算，得出综合评定结果。     

Worldwide effects of non-native species on species–area relationships

Non-native species have invaded most parts of the world, and the invasion process is expected to continue and accelerate. Because many invading non-native species are likely to become permanent inhabitants, future consideration of species-area relationships (SARs) should account for non-native species, either separately or jointly with native species. If non-native species occupy unused niches and space in invaded areas and extinction rate of native species remains low (especially for plants), the resultant SARs (with both native and non-native species) will likely be stronger. We used published and newly compiled data (35 data sets worldwide) to examine how species invasions affect SARs across selected taxonomic groups and diverse ecosystems around the world. We first examined the SARs for native, non-native, and all species. We then investigated with linear regression analyses and paired or unpaired t tests how degree of invasion (proportion of non-native species) affected postinvasion SARs. Postinvasion SARs for all species (native plus non-native) became significantly stronger as degree of invasion increased (r² = 0.31, p = 0.0006), thus, reshaping SARs worldwide. Overall, native species still showed stronger and less variable SARs. Also, slopes for native species were steeper than for non-native species (0.298 vs. 0.153). There were some differences among non-native taxonomic groups in filling new niches (especially for birds) and between islands and mainland ecosystems. We also found evidence that invasions may increase equilibrial diversity. Study of such changing species–area curves may help determine the probability of future invasions and have practical implications for conservation.     

炉内喷钙脱硫的模拟

煤粉炉内喷钙脱硫是应用较为广泛的脱硫技术，运用逾渗理论建立氧化钙脱硫模型，用来模拟煤粉炉喷钙脱硫过程，并对脱硫影响因素：ＳＯ２浓度、温度、Ｃａ／Ｓ比等进行了研究，模拟计算显示了这些因素对脱硫效果的影响，其结果与试验数据相一致。通过该模型计算可以优化脱硫过程，对煤粉炉内喷钙脱硫有重要的指导意义。     

工业废弃物在煤燃烧过程中脱硫行为的研究

提出了采用工业废弃物作为煤燃烧高温脱硫剂和催化促进剂的思路，对催化促进脱硫的机理进行试验研究，在此基础上提出几种不同配方的脱硫添加剂，并进行详细的试验研究，最终在6t/h工业链条上取得50％左右脱硫率的结果。     

空调生产有机废气治理工艺设计

简单介绍了化学吸收法处理空调生产有机废气的工艺流程、主要单元设备和工艺设计参数以及该工艺系统的运行效果     

偏转二次风系统600MW燃煤锅炉NO_x排放特性及数值模拟

某 6 0 0MW四角切圆燃烧锅炉 ,采用顶部燃尽风系统并配合使用偏转二次风系统 ,炉膛下部二次风大角度正切 ,上部二次风和OFA风反切消旋 ,在炉膛截面水平方向和炉膛高度方向形成分级燃烧 .运行结果表明 ,该燃烧器布置方式能抑制炉内结渣 ,减轻炉膛出口扭转残余并能降低NOx 排放量 .通过工况试验 ,将锅炉的氮氧化物排放水平降低到国家标准限定值以下 .采用数值计算对该炉炉内流动、传热、燃烧和氮氧化物生成过程进行模拟     

Land Use-related Chemical Composition of Street Sediments in Beijing

BACKGROUND: More than 10 million people are currently living in Beijing. This city faces severe anthropogenic air pollution caused by an intense vehicle increase (11% per year in China), coal combusting power plants, heavy industry, huge numbers of household and restaurant cookers, and domestic heating stoves. Additionally, each year dust storms are carrying particulate matter from the deserts of Gobi and Takla Makan towards Beijing, especially in spring. Other geogenic sources of particulate matter which contribute to the air pollution are bare soils, coal heaps and construction sites occurring in and around Beijing. Streets function as receptor surfaces for atmospheric dusts. Thus, street sediments consist of particles of different chemical compositions from many different sources, such as traffic, road side soils and industry. METHODS: Distributions and concentrations of various chemical elements in street sediments were investigated along a rural-urban transect in Beijing, China. Chemical elements were determined with X-ray fluorescence analysis. Factor analysis was used to extract most important element sources contributing to particulate pollution along a main arterial route of the Chinese capital. RESULTS AND DISCUSSION: The statistical evaluation of the data by factor analysis identifies three main anthropogenic sources responsible for the contamination of Beijing street sediments. The first source is a steel factory in the western part of Beijing. From this source, Mn, Fe, and Ti were emitted into the atmosphere through chimneys and by wind from coal heaps used as the primary energy source for the factory. The second source is a combination of traffic, domestic heating and some small factories in the center of Beijing discharging Cu, Pb, Zn and Sn. Calcium and Cr characterize a third anthropogenic element source of construction materials such as concrete and mortar. Beside the anthropogenic contamination, some elements like Y, Zr, Nb, Ce, and Rb are mainly derived from natural soils and from the deserts. This is supported by mineral phase analysis, which showed a clear imprint of material in road dusts coming from the West-China deserts. CONCLUSIONS: Our results clearly show that the chemical composition of urban road dusts can be used to identify distinct sources responsible for their contamination. The study demonstrates that the chemistry of road dusts is an important monitor to assess the contamination in the urban environment. Chemical composition of street sediments in Beijing comprises the information of different sources of atmospheric particles. RECOMMENDATIONS AND OUTLOOK: This study is only a small contribution to the understanding of substance fluxes related to Beijing's dust. More effort is required to assess Beijing's dust fluxes, since the dust harms the living quality of the inhabitants. Especially the measurable superimposing of long scale transported dust from dry regions with the anthropogenic polluted urban dust makes investigations of Beijing's dust scientifically valuable.     

基于RS和GIS的西部干旱区生态环境调控研究

实现生态环境优化调控与科学管理，是保护生态环境、促进社会经济与环境协调发展、建立人与自然和谐关系的重要举措。尤其是对生态环境十分脆弱的西部干旱地区，各级政府和学术界给予高度的重视。在定量研究生态环境调控的理论方法和具体操作过程中，需要借助遥感(RS)、地理信息系统(GIS)以及它们的结合等技术手段，来实现时空变化信息的实时、动态监测以及信息的提取、分析和处理。本文针对西部干旱区生态环境调控问题。提出一种RS和GIS支持下的生态环境调控量化研究方法，包括基于RS和GIS的西部干旱区生态环境量化指标体系、生态环境调控管理模型、调控方案优选与实施。并介绍一个应用例子。     

Association between pyrethroid exposure and risk of depressive symptoms in the general US adults

This study aimed to investigate the association between pyrethroid exposure and the risk of depressive symptoms in adults in the USA. Data of participants aged ≥20 years (n = 6455) from the National Health and Nutrition Examination Survey (NHANES, 2007–2014) were included. 3-Phenoxybenzoic acid (3-PBA), an adequately detected pyrethroid metabolite, was used as a biomarker to assess pyrethroid exposure. Depressive symptoms were defined as the Patient’s Health Questionnaire (PHQ-9) total score ≥10 or use of antidepressant. Multivariable logistic regression analyses were performed to examine the association between urinary 3-PBA levels and the risk of depressive symptoms. In this study, 1150 participants (weighted frequency, 18.45%) developed depressive symptoms. Participants in the highest tertile have a higher risk of depressive symptoms than those in the lowest tertile of urinary 3-PBA and weighted OR of 1.28 (95% CI, 1.00–1.63, P=0.019). There was a nonlinear association between urinary 3-PBA and depressive symptoms (P for nonlinearity = 0.034). Mediation analysis showed the mediating effect of trouble sleeping on the association of urinary 3-PBA with depressive symptoms was 28.8% (P = 0.006). Our findings indicate that pyrethroid exposure is associated with the increased risk of depressive symptoms, and trouble sleeping may mediated this association. Further studies should be conducted to validate our findings and elucidate their underlying mechanisms.