不同类型新车内醛酮类化合物的污染研究

随着人们对环境质量要求的提高,轿车逐步普及,车内空气质量正成为人们关注的焦点,特别是车内毒性较大的醛酮类物质更是受到普遍关注。选取了8种类型共93辆新车,在静止并且密闭条件下,对其内部环境的醛酮类物质的浓度水平进行测定分析。结果表明,大部分新车内都存在不同程度的醛酮类物质污染,总醛酮质量浓度为0.09～0.31mg/m3,平均质量浓度0.16mg/m3,其中甲醛为最高组分,其次为丙酮、正丁醛、乙醛,平均质量浓度分别为0.08、0.04、0.02、0.0003mg/m3。8类新车有7类都存在一定程度的甲醛超标,超标率为21%～50%,只有豪华车不超标。还对甲醛进行了癌症风险评价,结果表明风险值超过安全限值,存在癌症风险。     

基于分形求和模型的克拉玛依市空气质量评价

以克拉玛依市4个区2012年的大气自动监测数据为样本,基于分形求和模型,分析大气污染物的分布特征,利用分维数确定污染物浓度分布的随机程度,计算 SO2、NO2、PM10的大气环境背景值与标准值,确定适合于评价区域的ORAQI指数计算公式,并与 API指数作对比。ORAQI指数计算结果显示,克拉玛依市全年环境空气质量基本呈现“U”字形变化,春夏季大气质量好于秋冬季,全年空气质量有明显的季节变化,4个区中克拉玛依区空气质量相对较差,乌尔禾区空气质量最好。相对于 API指数的均匀分布结果,ORAQI指数具有更好的次要污染物体现能力,可以综合体现所评价的各项污染因子的贡献。     

企业生产环保投诉案件的环境监测分析

企业生产环保投诉案件的环境监测有别于委托监测和“三同时”验收监测。以杭州市某企业生产环保投诉案件为例,从案件内容、监测前期准备、现场踏勘、监测重点、规范性与准确性要求等方面对企业生产环保投诉案件的环境监测进行阐述与分析,重点是掌握监测前后企业和敏感目标的环境情况,制定必要的监测工作流程和技术规范,为环境管理正确处理该类案件提供科学依据。     

广东省空气质量等级预报准确性评估

对广东省空气质量等级预报准确性评估进行了探讨,结果表明,在不区分污染等级的情况下,2016年夏季广东各市的预报准确性差异较大,中山预报准确性达92%,是全省唯一一个准确性超过90%的城市,云浮最低,为53%。在区分污染等级时,实测为轻度及以上污染级别的情况下,各市的准确性普遍较低,仅佛山、东莞与广州的准确性达50%以上,而有11个城市的准确性为0。综合考虑不同污染级别的准确性得分后,佛山市排名第1,较不区分污染等级时的排名提前9名。指出,采用区分污染等级的预报效果评估办法更加适合广东空气污染较轻的区域。在首要污染物为臭氧的情况下,广东省平均的等级预报准确性低于首要污染物为其他物种的情况。     

One-step ball milling-prepared nano Fe2O3 and nitrogen-doped graphene with high oxygen reduction activity and its application in microbial fuel cells

• Nano Fe₂O₃ and N-doped graphene was prepared via a one-step ball milling method. • The maximum power density of Fe-N-G in MFC was 390% of that of pristine graphite. • Active sites like nano Fe₂O₃, pyridinic N and Fe-N groups were formed in Fe-N-G. • The improvement of Fe-N-G was due to full exposure of active sites on graphene. Developing high activity, low-cost and long durability catalysts for oxygen reduction reaction is of great significance for the practical application of microbial fuel cells. The full exposure of active sites in catalysts can enhance catalytic activity dramatically. Here, novel Fe-N-doped graphene is successfully synthesized via a one-step in situ ball milling method. Pristine graphite, ball milling graphene, N-doped graphene and Fe-N-doped graphene are applied in air cathodes, and enhanced performance is observed in microbial fuel cells with graphene-based catalysts. Particularly, Fe-N-doped graphene achieves the highest oxygen reduction reaction activity, with a maximum power density of 1380±20 mW/m² in microbial fuel cells and a current density of 23.8 A/m² at –0.16 V in electrochemical tests, which are comparable to commercial Pt and 390% and 640% of those of pristine graphite. An investigation of the material characteristics reveals that the superior performance of Fe-N-doped graphene results from the full exposure of Fe₂O₃ nanoparticles, pyrrolic N, pyridinic N and excellent Fe-N-G active sites on the graphene matrix. This work not only suggests the strategy of maximally exposing active sites to optimize the potential of catalysts but also provides promising catalysts for the use of microbial fuel cells in sustainable energy generation.     

Contribution of Ecosystem Services to Air Quality and Climate Change Mitigation Policies: The Case of Urban Forests in Barcelona,Spain

Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services “air purification,” “global climate regulation,” and the ecosystem disservice “air pollution” associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.     

Polychlorinated biphenyls (PCBs) in the atmosphere of sub-alpine northern Italy

The main objective of this work was to assess the atmospheric concentrations and seasonal variations of selected POPs in a sub-alpine location where few data are available. A monitoring and research station was set up at the JRC Ispra EMEP site (Italy). We present and discuss a one-year data set (2005-2006) on PCB air concentrations. ∑7PCBs monthly averaged concentration varied from 31 to 76 pg m⁻³. Concentrations in the gas phase (21-72 pg m⁻³) were higher than those in the particulate phase (3-10 pg m⁻³). Advection of air masses and re-volatilization from local sources seem to play a dominant role as drivers of PCB atmospheric concentrations in the area. Indications of seasonal variation affecting PCB congener patterns and the gas/particulate partitioning were found. Modeling calculations suggest a predominant importance of the wet deposition in this region (1 μg m⁻² yr⁻¹ ∑7PCBs yearly total wet deposition flux; 650-2400 pg L⁻¹ rainwater concentrations).     

PCDD/F and PCB multi-media ambient concentrations, congener patterns and occurrence in a Mediterranean coastal lagoon (Etang de Thau, France)

Ambient concentrations, congener patterns and multi-media distribution of PCDD/Fs and PCBs were determined in air, water, sediment and mussels in a semi-enclosed marine ecosystem (Thau lagoon, France). summation operator2,3,7,8-PCDD/F and summation operator7ICES PCB air concentrations (0.2-1.4 and 31-57pg m(-3), respectively) were typical of rural areas. Concentrations in the water column were very low for PCDD/Fs (163-476fg L(-1)) and low for PCBs (138-708pg L(-1)). PCDD/F and PCB concentrations found in surface sediment (0.15-1.6 and 2.5-33ng g(-1) d.w., respectively) and mussel (13-21pg g(-1) d.w. and 10-39ng g(-1) d.w., respectively) were medium levels. PCDD/F congener patterns observed in air, water particulate phase and sediments were similar suggesting direct coupling among these compartments and atmospheric inputs of PCDD/Fs into the lagoon. Conversely, for the same set of samples, similar patterns were not observed for PCBs in the mentioned compartments.     

Effect of short-term regional traffic restriction on urban submicron particulate pollution

During the 2013 and 2015 Lanzhou International Marathon Events(LIME1 and LIME2),the local government made a significant effort to improve traffic conditions and air quality by implementing traffic restriction measures. To fill the gap in information on the effect of short-period(several hours)traffic control on urban air quality,submicron particle size distributions and meteorological data were measured simultaneously during June 2013 and June 2015 in urban Lanzhou. The number and surface area concentrations of particles in the100–200 nm range declined by 67.2% and 65.0% for LIME1 due to traffic control,while they decreased by 39.2% and 37.1% for LIME2. The impact of traffic restriction on air pollution near the sampling site lagged behind the traffic control period for LIME2. In addition,the effect of traffic restriction on air pollution near the sampling site was dependent on the distance between the relative orientation of the sampling site and traffic-restricted zones,as well as meteorological conditions such as wind direction. The influence of traffic restrictions on the particle concentrations differed for different particle sizes. The size range most affected by traffic restriction was 60–200 and 60–300 nm for number and surface area concentrations in the urban environment,respectively,while for the particle volume concentration it was the 100–600 nm range. This study will provide a basis for implementation of future urban traffic-induced particulate pollution control measures.     

“大气十条”实施期间南京市PM2.5化学组成与来源的演变特征

为深入认识“大气污染防治行动计划”(“大气十条”)对大气细颗粒物(PM_2.5)污染的影响,基于“大气十条”实施期间南京市主城区(草场门)PM_2.5的化学组分监测资料,研究了PM_2.5主要组分的浓度和占比、富集因子和酸度等变化特征,并采用正定矩阵因子分解法(PMF)进行了PM_2.5的来源解析.结果发现,“大气十条”实施期间,南京市PM_2.5中硫酸根(SO₄^2-)的占比总体下降,但硝酸根(NO^-₃)和铵根(NH⁺₄)的占比均明显上升,两者的占比从2014年的25.58%上升到2017年的37.15%;碳组分(OC和EC)的浓度在“大气十条”早期出现大幅下降,但后期的下降趋势明显变缓,其中,有机碳(OC),特别是二次有机碳(SOC)的占比不降反升;PM_2.5酸性显著减弱,阴阳离子的摩尔当量比值(CE/AE)从2014年的0.83上升...