A study on the characteristics of silt loading on paved roads in the Seoul metropolitan area using a mobile monitoring system

This study is considered the first attempt to apply a mobile monitoring system to estimating silt loading on paved roads in a megacity such as the Seoul metropolitan area. Using a mobile monitoring system developed in 2005, we estimated silt loadings on representative paved roads in the Seoul metropolitan area, including the city of Incheon, over a period of 3 yr. The temporal and spatial characteristics of silt loading were investigated for the carefully selected roads that may reflect the characteristics of the cities of Seoul and Incheon. In this study, changes in the average silt loading values were investigated in terms of land use, the temporal resolution of data acquisition (i.e., seasonal, daily, three-hour scale), the road width or number of lanes, and rainfall, which may affect the characteristics of the average silt loading significantly. It was found that the advantages of using the mobile monitoring system are its ability to obtain a large quantity of silt loading data in a short period of time and over a wide area and its ability to create a silt loading map showing the relative magnitude of silt loading in relation to a specific location, which makes it possible to easily locate hot spots.     

A study on the characteristics of silt loading on paved roads in the Seoul metropolitan area using a mobile monitoring system

This study is considered the first attempt to apply a mobile monitoring system to estimating silt loading on paved roads in a mega-city such as the Seoul metropolitan area. Using a mobile monitoring system developed in 2005, we estimated silt loadings on representative paved roads in the Seoul metropolitan area, including the city of Incheon, over a period of 3 yr. The temporal and spatial characteristics of silt loading were investigated for the carefully selected roads that may reflect the characteristics of the cities of Seoul and Incheon. In this study, changes in the average silt loading values were investigated in terms of land use, the temporal resolution of data acquisition (i.e., seasonal, daily, three-hour scale), the road width or number of lanes, and rainfall, which may affect the characteristics of the average silt loading significantly. It was found that the advantages of using the mobile monitoring system are its ability to obtain a large quantity of silt loading data in a short period of time and over a wide area and its ability to create a silt loading map showing the relative magnitude of silt loading in relation to a specific location, which makes it possible to easily locate hot spots.

Implications: This study may be considered the first practical application of a mobile monitoring system to obtain the silt loading data on paved roads in a mega-city such as Seoul. It was found that the advantages of using the mobile monitoring system are its ability to obtain a large quantity of silt loading data in a short period of time and over a wide area and its ability to create a silt loading map showing the relative magnitude of silt loading in relation to a specific location, which makes it possible to easily locate hot spots to be cleaned cost-effectively by city officials.     

唐山市典型道路积尘负荷分布特征研究

为研究唐山市典型道路积尘负荷分布特征,于2019年1、4、7月基于样方真空吸尘法采集样品,通过筛分称重获得道路积尘负荷,并探讨其时空分布特征.结果表明:(1)不同类型道路积尘负荷排序为支路((0.70±0.85)g/m2)>环线((0.50±0.47)g/m2)>次干道((0.30±0.25)g/m2)>主干道((0....     

Road dust emissions from paved roads measured using different mobile systems

Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.     

Using a dispersion model to estimate emission rates of particulate matter from paved roads

From January 1996 to June 1997, we carried out a series of measurements to estimate emissions of PM₁₀ from paved roads in Riverside County, California. The program involved the measurement of upwind and downwind vertical profiles of PM₁₀, in addition to meteorological variables such as wind speed and vertical turbulent intensity. This information was analyzed using a new dispersion model that incorporates current understanding of micrometeorology and dispersion. The emission rate was inferred by fitting model predictions to measurements. The inferred emission factors ranged from 0.2 g VKT^-1 for freeways to about 3 g VKT^-1 for city roads. The uncertainty in these factors is estimated to be approximately a factor of two since the contributions of paved road PM₁₀ emissions to ambient concentrations were comparable to the uncertainty in the mean value of the measurement. At this stage, our best estimate of emission factor lies between 0.1 and 10 g VKT^-1; there is some indication that it is about 0.1 g VKT^-1 for heavily traveled freeways, and is an order of magnitude higher for older city roads. We found that measured silt loadings were poor predictors of emission factors.The measured emission factors imply that paved road emissions may contribute about 30% to the total PM₁₀ emissions from a high traffic area such as Los Angeles. This suggests that it is necessary to develop methods that are more reliable than the upwind–downwind concentration difference technique.     

砂对海水中溶解油的吸附及影响因素研究

以柴油污染的海水为对象，研究了砂对海水中溶解油的吸附作用及吸附的影响因素。结果表明，砂对溶解油的吸附符合Henry型吸附等温式，其吸附量随着砂粒粒径的减小、温度的降低和盐度的增加而增大。在影响吸附的3种因素中，粒径对吸附的影响最大。通过吸附热力学分析，推断砂对溶解油的吸附属于物理吸附。     

A review on the influencing factors of pavement surface temperature

Environmental Science and Pollution Research - Pavement surface temperature is of great significance to pavement performance and pavement design, as well as the development of cool pavements. The...     

垃圾焚烧重金属迁移特性及其影响因素

综述了城市固体垃圾（MSW）焚烧过程中的Hg、Cd、Pb、Cu,Zn,As和Cr等几种主要重金属污染源在焚烧过程中的迁移特性及其主要影响因素。将重金属在焚烧过程中的迂变归结为：蒸发、气相和表面反应、冷凝成核团聚和飞灰吸附等4个主要过程；而垃圾中重金属的初始浓度、原始垃圾的基体盐分（如Al、Si和K、Na等的存在形式）、垃圾中的C1（PVc和NaCl）和S的含量、垃圾的含水量以及焚烧过程中的运行参数（温度、滞留时间、氧化一还原气氛）等都会对焚烧过程的迁移规律产生影响。     

Scattering cross-section emission factors for visibility and radiative transfer applications: military vehicles traveling on unpaved roads

Emission factors for particulate matter (PM) are generally reported as mass emission factors (PM mass emitted per time or activity) as appropriate for air quality standards based on mass concentration. However, for visibility and radiative transfer applications, scattering, absorption, and extinction coefficients are the parameters of interest, with visibility standards based on extinction coefficients. These coefficients (dimension of inverse distance) equal cross-section concentrations, and, therefore, cross-section emission factors are appropriate. Scattering cross-section emission factors were determined for dust entrainment by nine vehicles, ranging from light passenger vehicles to heavy military vehicles, traveling on an unpaved road. Each vehicle made multiple passes at multiple speeds while scattering and absorption coefficients, wind velocity and dust plume profiles, and additional parameters were measured downwind of the road. Light absorption of the entrained PM was negligible, and the light extinction was primarily caused by scattering. The resulting scattering cross-section emission factors per vehicle kilometer traveled (vkt) range from 12.5 m2/vkt for a slow (16 km/ hr), light (1176 kg) vehicle to 3724 m2/vkt for a fast (64 km/hr), heavy (17,727 kg) vehicle and generally increase with vehicle speed and mass. The increase is approximately linear with speed, yielding emission factors per vkt and speed ranging from 4.2 m2/(vkt km/hr) to 53 m2/(vkt km/hr). These emission factors depend approximately linearly on vehicle mass within the groups of light (vehicle mass < or =3100 kg) and heavy (vehicle mass >8000 kg) vehicles yielding emission factors per vkt, speed, and mass of 0.0056 m2/(vkt km/hr kg) and 0.0024 m2/(vkt km/hr kg), respectively. Comparison of the scattering cross-section and PM mass emission factors yields average mass scattering efficiencies of 1.5 m2/g for the light vehicles and of 0.8 m2/g for the heavy vehicles indicating that the heavy vehicles entrain larger particles than the light vehicles.     

嗅觉实验配气方法的改进及影响因素研究

配制气体样品是异味测试及相关研究的基础工作,配气稳定性直接影响测试结果准确度。三点比较式臭袋法使用微量进样针量取并转移液体标准物质到3L无臭气袋的传统配气方法。对于异味阈值较小物质或样品浓度处于较低范围时,为了降低取样体积波动对配气精度和稳定性的影响。提出先将标准注入100mL玻璃注射器,充分挥发混匀后再转移部分气体到无臭气袋的两步式配气方法。结果表明,2种配气方法的准确度不存在显著差异,但两步式配气法的配气稳定性明显优于传统方法。此外,研究还发现,常见异味物质在被注人气袋后3min内便能完全挥发并混合均匀。除一些挥发性和吸附性极强的物质外,气袋内的异味物质气体浓度能在配好后20min内基本保持不变。     

锶在改性介质中的吸附规律及其影响因素研究

通过室内等温静态批量平衡吸附实验,采用2种常见的等温吸附方程(Freundlich方程、Langmuir方程)对锶在3种不同润湿性的石英砂中的吸附行为进行了回归拟合。结果表明,介质润湿性对锶的吸附会产生重要的影响,润湿性较强的亲水性石英砂的吸附性能明显优于疏水性石英砂;从Freundlich方程和Langmuir方程拟合结果来看,两者均具有理想的相关性,但普通石英砂和亲水性石英砂的等温吸附式更符合Langmuir方程,而疏水性石英砂采用Freundlich方程拟合的相关性更好。     

光能自养生物膜形成机制及脱氮影响因素的研究进展

光能自养生物膜是一个由复杂微生物群落构成的相对稳定的微生态系统,微生物细胞及非生物物质镶嵌在微生物分泌的有机聚合物基质上,其显著特征是膜表面寄居着光能自养生长的微生物,并能在碳源缺乏条件下完成生物脱氮.总结了光能自养生物膜的形成机制,概述了光照、温度、微生物种类、营养物浓度对光能自养生物膜脱氮的影响,指出光能自养生物膜...     

天津市煤炭消费的行业结构和影响因素分析

分析了天津市煤炭消费的行业结构和影响因素,旨在为天津市削减煤炭消费总量提供参考依据。由于煤炭大部分用于生产二次能源,计算了天津市生产各行业消费的二次能源所需的煤炭量,将其与各行业的煤炭终端消费量综合考虑。结果显示,天津市煤炭消费的行业集中度较高,工业占大部分比例,其中又以钢铁、化工行业最突出,同时生活消费和第三产业的煤炭消费量也不容忽视。与全市煤炭消费总量灰色关联度最高的指标为城市建设用地数量和人均生活能源消费量。     

微波修复氯丹污染土壤中氯丹降解的影响因素研究

对微波修复氯丹污染土壤进行研究,重点考察了含水率、微波辐射时间、碱浓度、活性炭添加量和土壤量对其中氯丹降解的影响。结果表明:(1)总体上,氯丹降解率随着含水率的增加而先增加后减少,随着微波辐射时间的延长而增加。当含水率为20%、微波辐射15min后,α-氯丹和γ-氯丹的降解率分别增加到65%和56%。(2)总体上,氯丹降解率随着微波辐射时间的延长而不断增加,7min后氯丹的降解过程基本趋于平衡。10mol/L氢氧化钠溶液存在条件下氯丹降解效果最好,15min时α-氯丹和γ-氯丹的降解率分别为94%和82%。(3)氢氧化钠溶液最佳摩尔浓度为10mol/L。(4)添加1.0g活性炭条件下,氯丹降解率随着微波辐射时间延长而迅速增加,15min时α-氯丹和γ-氯丹的降解率分别为98%和94%。(5)当土壤和活性炭的质量比固定为15∶1时,随着土壤量的增加,氯丹降解率明显增加。     

Research on the influencing factors of reverse logistics carbon footprint under sustainable development

With the concerns of ecological and circular economy along with sustainable development, reverse logistics has attracted the attention of enterprise. How to achieve sustainable development of reverse logistics has important practical significance of enhancing low carbon competitiveness. In this paper, the system boundary of reverse logistics carbon footprint is presented. Following the measurement of reverse logistics carbon footprint and reverse logistics carbon capacity is provided. The influencing factors of reverse logistics carbon footprint are classified into five parts such as intensity of reverse logistics, energy structure, energy efficiency, reverse logistics output, and product remanufacturing rate. The quantitative research methodology using ADF test, Johansen co-integration test, and impulse response is utilized to interpret the relationship between reverse logistics carbon footprint and the influencing factors more accurately. This research finds that energy efficiency, energy structure, and product remanufacturing rate are more capable of inhibiting reverse logistics carbon footprint. The statistical approaches will help practitioners in this field to structure their reverse logistics activities and also help academics in developing better decision models to reduce reverse logistics carbon footprint.     

好氧颗粒污泥形成与运行稳定性的影响因素试验分析

用普通絮状污泥作为接种污泥,用SBR作为反应器,分析了高径比、污泥容积负荷以及营养比例(BOD5:N:P)等因素对好氧颗粒污泥形成的影响.试验结果表明,高径比对好氧颗粒污泥的形成有直接关系;污泥容积负荷越高、碳氮比正常、磷源缺乏越易诱导好氧颗粒污泥的骨架丝状菌的生长,可以促进好氧颗粒污泥的提前形成,但是越易引起粘性膨胀的出现.在高径比为38;6,污泥容积负荷为1.67 kg/(m3·d).BOD5:N:P为100:5:1,沉淀时同为2 h时,其好氧颗粒污泥形成时间为17个周期,成熟时间为23个周期,粒径为2～3 mm,平均污泥沉降比(SV)为29.0%,对模拟废水COD的平均去除率达94.3%.     

农田氮素淋溶损失影响因素及防治对策研究

农田氮素损失是造成农业非点源污染的主要原因之一,其中由于大量施用氮肥引起的土壤氮素淋溶损失又是农田氮素损失的重要途径.因此,农田氮素损失研究已成为国际土壤化学和环境科学领域研究的热点问题之一.根据近年来国内外在农田氮素运移领域的研究成果,从降雨和灌溉、施肥状况、土壤性质、耕作方式、作物种类和种植方式等方面分析了影响农田氮素淋溶损失的主要因素,提出了改进施肥方式、优化氮肥管理、推广缓释氮肥以及改善土地利用方式等提高氮肥利用率、减小氮素淋溶损失的防治对策.     

Modeling the influencing factors of electronic word-of-mouth about CSR on social networking sites

Environmental Science and Pollution Research - Corporate social responsibility (CSR) information can now be disseminated via social networking sites. An organization’s image and upcoming...     

中国西部地区环境投资效率及其影响因素研究

采用数据包络分析(DEA)—Tobit两阶段模型法,对西部地区的环境投资效率及其影响因素进行实证分析。结果表明,在DEA核算期(2003—2010年)内,西部地区的环境投资效率与中国平均水平相近,且均远高于东部地区;2003—2010年,西部地区全部处于纯技术有效和规模有效的省份只有广西和贵州,而其他省区均不同程度地存在纯技术无效或规模无效现象,这些省区不仅存在环保投资资金管理和经营水平上的非有效性,而且其环境治理投入规模也存在非合理性;对环境投资效率的影响因素进行Tobit回归分析后发现,经济规模和产业结构对环境投资效率有正向促进作用,对外贸易程度、政府规制和公民环保意识与环境投资效率则存在负相关关系。