Characterization of volatile organic compounds in the urban area of Beijing from 2000 to 2007

Beijing is one of the most polluted cities in the world. In this study, the long-term and continuous measurements of volatile organic compounds (VOCs) in the urban area of Beijing, specifically at Beijing 325 m Meteorological Tower, were conducted from 2000 to 2007. The annual record of VOC trends exhibited in two different phases was separated in 2003. Records show that VOC concentrations increased from 2000 to 2003 due to the abrupt increase in vehicle number. Contrarily, since 2003, there had been a decrease in VOCs concentrations as the policy on gasoline and air pollution was implemented. Toluene, benzene, and i-pentane are the chemicals that abound in and are directly related to vehicle activity, such as in vehicle exhaust and gasoline evaporation. Furthermore, records indicate that there had been seasonal variation in VOCs levels in that VOCs level in summer is higher than that in winter. As such, temperature is considered to significantly contribute to VOCs in Beijing. Records also show that VOCs level was high in the morning and during rush hours in the evening. In contrast, VOCs level was low during midday due to photochemical destruction with OH radical and dilution effect. In this study, a particular benzene to toluene ratio range (0.4-1.0) was used as the indicator of air propelled by vehicular exhaust. We also applied the correlation coefficients between BTEX and i-pentane to evaluate evaporation influence to ambient BTEX in the Beijing urban area.     

山西地区气溶胶垂直分布特征与光学特性的飞机观测研究

利用2013年8月,以Y-12飞机为空中观测平台,搭载PCASP、SMPS、AMS、CCN200、TSI-3563型积分浊度仪和美国MAAP-5012型多角度吸收光度计等多种气溶胶观测仪器,首次对黄土高原大气气溶胶特性开展联合观测的资料,对大气气溶胶粒度,散射和颗粒吸收特性进行了分析,研究了区域气溶胶的空间分布及理化特征.结果表明黄土高原特殊地形区域气溶胶的微物理特性较稳定,但随探测时气象条件的变化,散射系数仍然出现波动;区域气溶胶中以细粒子为主;三个波长散射系数变化趋势非常一致,可以认为探测过程中气溶胶的微物理特性基本不变,而仅仅是浓度在改变;散射系数的变化趋势与体积浓度的变化趋势基本一致;其高值区与大气高湿区的正相关性比较明显;四次探测过程中小尺度粒径的气溶胶粒子为优势粒子;后向轨迹分析可知研究区域大部分气溶胶粒子都来源于高空,由蒙古、内蒙、甘肃、陕西等地远距离输送而来.     

Precision Measurements from Very-Large Scale Aerial Digital Imagery

Managers need measurements and resource managers need the length/width of a variety of items including that of animals, logs, streams, plant canopies, man-made objects, riparian habitat, vegetation patches and other things important in resource monitoring and land inspection. These types of measurements can now be easily and accurately obtained from very large scale aerial (VLSA) imagery having spatial resolutions as fine as 1 millimeter per pixel by using the three new software programs described here. VLSA images have small fields of view and are used for intermittent sampling across extensive landscapes. Pixel-coverage among images is influenced by small changes in airplane altitude above ground level (AGL) and orientation relative to the ground, as well as by changes in topography. These factors affect the object-to-camera distance used for image-resolution calculations. ‘ImageMeasurement’ offers a user-friendly interface for accounting for pixel-coverage variation among images by utilizing a database. ‘LaserLOG’ records and displays airplane altitude AGL measured from a high frequency laser rangefinder, and displays the vertical velocity. ‘Merge’ sorts through large amounts of data generated by LaserLOG and matches precise airplane altitudes with camera trigger times for input to the ImageMeasurement database. We discuss application of these tools, including error estimates. We found measurements from aerial images (collection resolution: 5–26 mm/pixel as projected on the ground) using ImageMeasurement, LaserLOG, and Merge, were accurate to centimeters with an error less than 10%. We recommend these software packages as a means for expanding the utility of aerial image data.     

国外有害废物管理的动向与指南

简要介绍了德国、荷兰和美国等工业化国家的有害废物管理的新动向,以及由工业化国家在有害废物管理中取得的成功经验中,适用于发展中国家的有害废物的基本管理方法和可以作为借鉴的实用措施的指南性环境管理框架。     

室内空气污染物的种类及控制措施

室内空气污染物包括悬浮固体污染物和气体污染物。其中可吸入颗粒物对人体呼吸系统有极大危害，引起肺炎、肺癌等疾病，主要来源于燃料的燃烧、吸烟以及由室外进入室内的颗粒物。气体污染物主要包括有机气体污染物(挥发性有机物、甲烷等)和无机气体污染物(SO2、NOx、CO等)，它们可引起病态建筑综合症、化学物质过敏症(MCS)等相关病症。本文分析了室内空气污染的影响因素，并据此提出了控制室内空气污染以及提高室内空气质量的方法与措施。     

Summer air quality over an artificial lake

In the summer of 1998, the air quality (indicators: CO, NO, NO₂, O₃) above the water surface of the Lake Balderey (Essen, Ruhr area, North Rhine-Westphalia, Germany), an artificial lake used for recreation purposes, was measured using the Fourier transform infrared spectroscopy (FTIR) and differential optical absorption spectroscopy (DOAS) remote measurement methods. The lake, with an area of 3 km² was created by damming the Ruhr and is surrounded by higher ground. In calm, bright weather conditions, this location results in a low-exchange situation (formation of temperature inversions, cold air dynamics) with a sustained impact on pollutant concentrations over the lake. The results of trace substance measurements (1/2 h mean values) were compared with values from comparison stations (suburban, high traffic and forest) located outside the area of the lake. In general, it was found that mean CO and NO concentrations over the lake were very low (0.3 ppm and 7.5 ppb, respectively). NO₂ values (15 ppb) were some 3.5 times higher than those recorded at the forest station and O₃ values, at 27 ppb, almost reached the same level as at the forest station (30 ppb). Mass flow densities as a function of wind direction, diurnal courses, differences between weekdays and weekends and comparisons with air quality standards are presented for the lake station.     

Application of in-situ measurement to determine Cs in the Swiss Alps

Establishment of ¹³⁷Cs inventories is often used to gain information on soil stability. The latter is crucial in mountain systems, where ecosystem stability is tightly connected to soil stability. In-situ measurements of ¹³⁷Cs in steep alpine environments are scarce. Most studies have been carried out in arable lands and with Germanium (Ge) detectors. Sodium Iodide (NaI) detector system is an inexpensive and easy to handle field instrument, but its validity on steep alpine environments has not been tested yet. In this study, a comparison of laboratory measurements with GeLi detector and in-situ measurements with NaI detector of ¹³⁷Cs gamma soil radiation has been done in an alpine catchment with high ¹³⁷Cs concentration (Urseren Valley, Switzerland). The aim of this study was to calibrate the in-situ NaI detector system for application on steep alpine slopes. Replicate samples from an altitudinal transect through the Urseren Valley, measured in the laboratory with a GeLi detector, showed a large variability in ¹³⁷Cs activities at a meter scale. This small-scale heterogeneity determined with the GeLi detector is smoothed out by uncollimated in-situ measurements with the NaI detector, which provides integrated estimates of ¹³⁷Cs within the field of view (3.1 m²) of each measurement. There was no dependency of ¹³⁷Cs on pH, clay content and carbon content, but a close relationship was determined between measured ¹³⁷Cs activities and soil moisture. Thus, in-situ data must be corrected for soil moisture. Close correlation (R² = 0.86, p < 0.0001) was found for ¹³⁷Cs activities (in Bq kg⁻¹) estimated with in-situ (NaI detector) and laboratory (GeLi detector) methods. We thus concluded that the NaI detector system is a suitable tool for in-situ measurements in alpine environments. This paper describes the calibration of the NaI detector system for field application under elevated ¹³⁷Cs activities originating from Chernobyl fallout.     

Indoor radon levels in Greek schools

Radon and gamma dose rate measurements were performed in 512 schools in 8 of the 13 regions of Greece. The distribution of radon concentration was well described by a lognormal distribution. Most (86%) of the radon concentrations were between 60 and 250 Bq m⁻³ with a most probable value of 135 Bq m⁻³. The arithmetic and geometric means of the radon concentration are 149 Bq m⁻³ and 126 Bq m⁻³ respectively. The maximum measured radon gas concentration was 958 Bq m⁻³. As expected, no correlation between radon gas concentration and indoor gamma dose rate was observed. However, if only mean values for each region are considered, a linear correlation between radon gas concentration and gamma dose rate is apparent. Despite the fact that the results of radon concentration in schools cannot be applied directly for the estimation of radon concentration in homes, the results of the present survey indicate that it is desirable to perform an extended survey of indoor radon in homes for at least one region in Northern Greece.     

Hydrogen explosion incident mitigation in steam reforming units through enhanced inspection and forecasting corrosion tools implementation

Hydrogen (H₂) explosion effects recently examined, are confirming the devastating loss scenarios to humans, environment, assets, and associated business interruption. H₂ production is a core process in refineries used in further process steps. Steam reforming of natural gas or a mix with naphtha or LPG is a common hydrogen production technique, where the latest technologies have adopted enhanced metallurgies to minimize explosion risk and the associated maintenance cost following plant degradation owing to corrosion effects. However, corrosion rates are still high in specific areas of piping and process equipment. The aim of this paper is to present a methodology based on semi-quantitative RBI modeling according to regulations by API and recent EN standards, adopting a family of linear regression forecasting models that depict the yearly corrosion rate (per corrosion loop) of a hydrogen production steam reforming unit; this is done under different operating conditions (e.g., temperature, pressure, and fluid speed), metallurgy and other related physicochemical variables. The model is based on the examination of both ultrasonic wall thinning measurements and the examination of quantitative crosslinking total corrosion effects along with the physicochemical properties prevailing in different plant corrosion loops. The outcome of the regression analysis is an expansive family of multivariable equations describing, with a defined accuracy, the yearly corrosion rate and associated lifespan forecast per corrosion loop, and per examined part. These equations were further utilized in a custom-made database that can be used as an additional loss prevention tool by the hydrogen production unit management team. Evaluation results regarding the tool efficiency are presented in the following of this paper.     

Measurement techniques for organizational safety causal models: Characterization and suggestions for enhancements

Through a review of literature from diverse disciplines with actual and potential application to causal modeling of organizational safety risk, this paper explores issues regarding measurement techniques in a quantitative safety analysis context. The interdependencies of modeling perspectives, constructs, and measures are indentified, leading to (a) characterization and classification of measurement techniques, (b) suggestions on the selection of appropriate measurement methods for different types of model constructs including individual-level, global, configural, and shared, and (c) discussion of the modeling implications of interactions between measurement, constructs, and causal paths. A multi-dimensional perspective is offered through combinations of different “measurement methods” and “measurement bases”. A Bayesian approach is also proposed to operationalize the multi-dimensional measurements. Examples are provided to help explain the roles of these measurements in capturing the relation between organizational factors and safety performance. This paper is a product of research which has the primary purpose of extending Probabilistic Risk Assessment (PRA) modeling frameworks to include the effects of organizational factors as the fundamental causes of accidents and incidents.