Characteristics of the pollutant emissions in a tunnel of Shanghai on a weekday

Tunnel displays a typical semi-closed environment, and multitudes of the pollutants tend to accumulate. The samples of gaseous pollutants and particulate matter(PM) were collected from the Xiangyin tunnel at Shanghai to investigate the characteristics of the pollutant emissions. The results indicated that both gaseous pollutants and PM exhibited much higher concentrations during the rush hours in the morning and at night due to vehicle emission. Two peaks of the PM concentration were observed in the scope of 0.7‐1.1 and 3.3–4.7 μm, accounting for 14.6% and 20.3% of the total concentrations, respectively.Organic matter(OM), EC, and many water-soluble ions were markedly higher at the rush hours in the morning than those at night, implicating comprehensive effects of vehicle types and traffic volume. The particle number concentrations exhibited two peaks at Aitken mode(25 nm and 100 nm) and accumulation mode(600 nm), while the particle volume concentration displayed high values at the accumulation mode(100–500 nm) and coarse mode(2.5–4.0 μm). The peak around 100 nm was detected in the morning rush hours, but it diminished with the decrease of the traffic volume. Individual-particle analysis revealed that main particles in the tunnel were Fe-rich particles, K-rich particles, mineral particles,Ca–S rich particles and Al–Si particles. The particles collected at the rush hours displayed marked different morphologies, element concentrations and particle sizes compared to the ones collected at the non-rush period. The data presented herein could shed a light on the feature of vehicle emissions.     

Enhanced photocatalytic activity of rGO/TiO2 for the decomposition of formaldehyde under visible light irradiation

Due to the low concentration of indoor air contaminants,photocatalytic technology shows low efficiency for indoor air purification.The application of TiO_2 for photocatalytic removal of formaldehyde is limited,because TiO_2 can only absorb ultraviolet(UV) light.Immobilization of TiO_2 nanoparticles on the surface of graphene can improve the visible light photocatalytic activity and the adsorption capacity.In this study,rGO(reduced graphene oxide)/TiO_2 was synthesized through a hydrothermal method using titanium tetrabutoxide and graphene oxide as precursors,and was used for the degradation of low concentration formaldehyde in indoor air under visible light illumination.Characterization of the crystalline structure and morphology of rGO/TiO_2 revealed that most GO was reduced to rGO during the hydrothermal treatment,and anatase TiO_2 nanoparticles(with particle size of 15–30 nm) were dispersed well on the surface of the rGO sheets.rGO/TiO_2 exhibited excellent photocatalytic activity for degradation of formaldehyde in indoor air and this can be attributed to the role of rGO,which can act as the electron sink and transporter for separating photo-generated electron–hole pairs through interfacial charge transfer.Furthermore,rGO could adsorb formaldehyde molecules from air to produce a high concentration of formaldehyde on the surface of rGO/TiO_2.Under visible light irradiation for 240 min,the concentration of formaldehyde could be reduced to 58.5 ppbV.rGO/TiO_2 showed excellent moisture-resistance behavior,and after five cycles,r GO/TiO_2 maintained high photocatalytic activity for the removal of formaldehyde(84.6%).This work suggests that the synthesized rGO/TiO_2 is a promising photocatalyst for indoor formaldehyde removal.     

四川省人为源大气污染物排放清单及特征

在收集四川省各城市人为污染源活动水平数据基础上,基于自下而上和自上而下结合的清单构建方法,选取排放因子并结合GIS技术,建立了该地区2015年1 km×1 km人为源大气污染物排放清单.结果表明,2015年四川省人为源SO_2、NO_x、CO、PM_(10)、PM_(2.5)、BC、OC、VOCs和NH_3排放量分别为444.9×10~3、820.0×10~3、3 773.1×10~3、1 371.6×10~3、537.5×10~3、28.7×10~3、53.1×10~3、923.6×10~3和988.0×10~3t.电厂和工业锅炉等燃煤排放贡献了95%以上的SO_2,移动源、化石燃料燃烧源和工艺过程源分别贡献了54%、23%和20%的NO_x,以钢铁和建材制造为主的工艺过程源分别贡献了20%的PM_(10)和34%的PM_(2.5),以道路扬尘为主的扬尘源分别贡献了60%的PM_(10)和35%的PM_(2.5),生物质燃烧分别贡献了33%的BC和51%的OC,以机械加工、建筑装饰、电子设备制造、印刷和家具等行业为主的溶剂使用源贡献了46%的VOCs,NH_3主要来自畜禽养殖和氮肥施用等农业部门排放,分别占总排放量的70%和25%.污染物空间分布结果显示,四川省各项大气污染物主要集中分布于人口最为密集,农业和工业均较为发达的四川盆地和攀枝花部分区域,其中,以成都、德阳和绵阳为代表的成都平原城市群为四川盆地内的主要排放高值区域.所建立的排放清单存在一定不确定性,后续研究中应针对活动水平数据获取的不足开展数据收集工作,加强排放贡献较大典型污染源的排放因子本地化研究工作,逐步完善四川省大气污染物排放清单,为四川省复合型大气污染研究和防治提供科学支撑.     

2006—2015年中国电力碳足迹及其生态压力分析

电力行业是我国节能减排的主力军.本文根据电力来源多样性特征,采用IPCC计算方法,结合净初级生产力模型,定量分析了中国2006-2015年电力消费碳足迹及其生态压力的变化,并将电力碳足迹生态压力与人均GDP进行脱钩分析.结果表明,2006-2015年,电力消费碳排放量经历了先升后降两个阶段,其中,2006-2013年,碳排放量稳步上升,2013年后开始逐渐下降,电力碳足迹生态压力与人均GDP之间主要呈弱脱钩关系,但在2013-2015年,开始出现强脱钩状态.可见在国家″十二五″政策引导下,推动经济结构转型调整,促进电力产业节能减排,已获得显著成效,但仍需继续努力,缓解电力消费过程给生态环境带来的压力.     

系统工程视野下的再生水饮用回用安全保障体系构建

再生水是就地可取、稳定可靠的城市第二水源.再生水饮用回用（补充水源）技术经济性可行,是解决城市缺水问题的重要途径和构建可持续水循环系统的重要组成部分.作为具有复杂系统特征的非传统供水工程,再生水饮用回用的关键是保障水质安全稳定和系统可靠高效运行,因此需要构建包括水质安全管理、健康风险评价和多重屏障工程措施在内的安全保障体系.水质安全管理方面需建设包括制订科学的饮用回用水质标准和再生水处理工艺要求,建立针对再生水处理工艺和饮用回用全系统的危害分析关键控制点管理（HACCP）体系,并加强水质安全监管和认证.健康风险评价方面需开展全方位、统筹性和持续性的化学污染物和微生物风险评价方法.工程措施方面需建设包括源头控制、再生水厂净化、环境缓冲和饮用水厂净化在内的多重屏障系统,以确保水质安全.在多重屏障系统中,再生水厂是保障饮用回用水质安全的核心环节,“反渗透-高级氧化”和“臭氧-生物活性炭”是再生水处理的可行工艺.今后需深入、持续开展新兴高风险污染物控制技术、再生水环境储存和饮用回用模式等方面的研究.      

一种适用于不同航天器电子产品的热循环试验的循环次数确定方法

目的给不同航天器电子设备提供合适的常压热循环试验条件,使其在不同的循环次数和温度范围下获得相等的应力筛选,提出一种定制化的热循环次数的确定方法。方法基于热疲劳理论,分析典型航天器热致故障机理,并综合考虑航天器设计、材料、工艺的特点以及历史故障数据分布的影响,引入综合疲劳加速指数和故障沉淀率,形成航天器综合疲劳寿命等效等式。最后以某航天器典型电子设备为例,给出该方法所确定的试验条件。结果该方法能降低航天器欠试验或过试验的风险。     

Causes of phytotoxicity of metsulfuron-methyl bound residues in soil

The bioavailability and phytotoxicity of bound residues of metsulfuron-methyl were studied using 14C-labeling and bioassay with oil rape (Brassica napus L.). Soil bound residues at the concentration of 0.27 and 0.53 nmol g(-1) resulted in significant inhibition of oil rape seedling growth. The biologically active component of the bound residues was identified to be metsulfuron-methyl parent compound. Other metabolites, including the hydrolysis product 2-methylformate-benzenesulfonamide, showed no toxicity to the test species. This study suggests that residues of metsulfuron-methyl bound previously to the soil matrix could be again released upon planting. The phytotoxicity of metsulfuron-methyl bound residues was mainly caused by the metsulfuron-methyl parent compound that became available during plant growth.     

杭州市郊菜区大气及蔬菜中氟化物的含量和分布

本文分析调查了杭州市郊菜区大气及一些主要蔬菜中氟化物的含量及分布，并对蔬菜中氟化物含量与大气氟污染的关系进行了相关分析。结果表明，杭州市郊菜区个别蔬菜中氟化物含量已超过有关标准，这主要与工业污染源的分布有关；蔬菜中氟化物含量与大气氟浓度之间存在着明显的相关关系。     

长链烷烃降解菌alkB片段的分离和鉴定

分离并鉴定了长链烷烃降解菌Pseudomonasaeruginosa1785和P.marginata766烃羟化酶基因alkB片段.根据烃羟化酶的保守氨基酸序列,设计兼并引物,扩增P.aeruginosa1785和P.marginata766的alkB片段,获得了目标产物.经DNA测序和氨基酸序列分析,证实目标片段编码的肽段含有烃羟化酶的特征基序.由此确认采用该方法分离到了长链烷烃降解基因的alkB同源体片段.DNA序列比对结果表明,P.aeruginosa1785和P.marginata766的alkB片段与P.aeruginosaPAO1的alkB1和alkB2的相似性分别达到95.7%和94.8%.这些alkB片段可用于分析烃降解微生物群落结构.图3表2参11     

若尔盖湿地3种无尾两栖类不同发育阶段的生态位宽度

研究了若尔盖湿地国家级自然保护区的3种无尾两栖类,高原林蛙(Rana kukunoris)、倭蛙(Nanorana pleskei)和岷山蟾蜍(Bufo minshanicus)的成体和亚成体在7个生境因子(牧场性质、牛粪数量、植被高度、植被盖度、距水塘距离、地表温度、地表湿度)上的生态位宽度.结果表明,岷山蟾蜍成体在牧场性质、牛粪数量、植被盖度、地表温度、地表湿度5个维度上的生态位宽度最窄,其亚成体在牧场性质、牛粪数量、植被高度、距水塘距离、地表湿度5个维度上的生态位宽度最宽;倭蛙亚成体在牧场性质、牛粪数量、地表温度、地表湿度4个维度上的生态位宽度最窄,而其成体在牛粪数量、植被高度、植被盖度、距水塘距离4个维度上的生态位宽度最宽;高原林蛙在微气候因子的两个维度上具有较大的生态位宽度值,而在水塘距离维度上的生态位宽度值则很小.当人类活动导致生境变更时,倭蛙的反应最为敏感;比较3种无尾两栖类在不同生长阶段(成体、亚成体)的生态位宽度,发现它们利用资源的策略不同.表3参16