A Method for Locating Influential Pollution Sources and Estimating Their Contributions

This work develops a source-oriented approach to locate the influential pollution sources and estimate their contributions to pollutant concentrations observed at a receptor site. The domain containing possible influential pollution sources is divided into systematic grid cells, and the influential grid sources are determined based on the locations of the segment endpoints of air trajectories arriving at the receptors. The contribution of each grid source is initially calculated using a formula derived from a Lagrangian box model and including the effects of source emissions, atmospheric dilution, and chemical transformation and deposition. The formula is described in detail in this study. Finally, the average contribution of each grid source is determined based on numerous analyzed events. The proposed approach was used to locate influential pollution sources and determine their contributions to a rural monitoring station during periods of high SO₂ pollution in southern Taiwan. The contributions of sources in various 2 km by 2 km grid cells, five districts, three source categories, 8 industrial areas, and a power plant were evaluated. The results show that the major influential sources were in the northwestern region of south Taiwan, and belonged to three district and point sources. Furthermore, two industrial areas close to the evaluated stations were also very significant, and contributed about 30% of the total pollution.     

Assessment of Air Quality After the Implementation of Compressed Natural Gas (CNG) as Fuel in Public Transport in Delhi, India

Public transport in Delhi was amended by the Supreme Court of India to use Compressed Natural Gas (CNG) instead of diesel or petrol. After the implementation of CNG since April 2001, Delhi has the highest fraction of CNG-run public vehicles in the world and most of them were introduced within 20 months. In the present study, the concentrations of various criteria air pollutants (SPM, PM₁₀, CO, SO₂ and NO_x) and organic pollutants such as benzene, toluene, xylene (BTX) and polycyclic aromatic hydrocarbons (PAHs) were assessed before and after the implementation of CNG. A decreasing trend was found for PAHs, SO₂ and CO concentrations, while the NO_x level was increased in comparison to those before the implementation of CNG. Further, SPM, PM₁₀, and BTX concentrations showed no significant change after the implementation of CNG. However, the BTX concentration demonstrated a clear relation with the benzene content of gasoline. In addition to the impact of the introduction of CNG the daily variation in PAHs levels was also studied and the PAHs concentrations were observed to be relatively high between 10 pm to 6 am, which gives a proof of a relation with the limited day entry and movement of heavy vehicles in Delhi.     

3种叶面阻控剂对水稻籽粒Cd、As富集影响效果

为探究3种叶面阻控剂单施及配施对水稻籽粒Cd、 As富集的影响,以松雅早1号和五香优粤农丝苗分别为供试早、 晚稻品种,采用盆栽试验方法,设置9个处理：对照（CK）,单施半胱氨酸（L-Cys）、 硫化钾（K₂S）和磷酸氢二钾（K₂HPO₄）,以及两种叶面阻控剂配施（L-Cys与K₂S低/高浓度配施、 L-Cys与K₂HPO₄低/高浓度配施、 K₂S与K₂HPO₄低浓度配施）,研究叶面阻控剂单施及配施对水稻籽粒Cd、 As富集的影响.结果表明： ①叶面阻控剂单施及配施均能使水稻籽粒中Cd、 As含量降低,除L-Cys与K₂S/K₂HPO₄低浓度配施处理外,其余处理糙米Cd含量均低于安全生产标准（0.20 mg·kg^-1）;与CK相比,施加叶面阻控剂的处理使早晚稻糙米无机砷（IAs）含量分别降低4.68%~56.75%和2.84%~16.91%. ②叶面阻控剂单施及配施可以促进Cd、 As从茎向叶的转运,抑制Cd、 As从叶向籽粒的转运,并使Cd、 As固存在叶片细胞壁中,从而降低水稻籽粒中的Cd、 As含量. ③L-Cys与K₂S高浓度配施处理降低糙米Cd、 As效果最好,使早、 晚稻糙米Cd含量分别降低37.64%、 26.37%,且均低于0.20 mg·kg^-1;使早稻糙米无机砷ω（IAs）降至0.10 mg·kg^-1（<0.20 mg·kg^-1）.研究结果为实现重金属污染耕地农作物安全生产提供理论依据和数据支持.     

铁路危险货物运输安全监管体系的思考与建议

为确保铁路危险货物运输的安全性,通过梳理铁路危险货物运输现状,结合铁路体制改革、危险货物运输体系的新特点,分别从危险货物的规章制度、安全评价、人员培训、应急预案、救援设备设施、运输环境等方面分析铁路危险货物运输存在的问题。研究表明:优化后的安全管理模式可形成全程监管链条,提高危险货物运输作业的规范性,提高危险货物风险处理能力和反应速度,减小危险货物运输风险程度。     

Geochemical and solute transport modelling for CO2 storage, what to expect from it?

Geochemistry plays an important role when assessing the impact of CO₂ storage. Due to the potential corrosive character of CO₂, it might affect the chemical and physical properties of the wells, the reservoir and its surroundings and increase the environmental and financial risk of CO₂ storage projects in deep geological structures. An overview of geochemical and solute transport modelling for CO₂ storage purposes is given, its data requirements and gaps are highlighted, and its progress over the last 10 years is discussed. Four different application domains are identified: long-term integrity modelling, injectivity modelling, well integrity modelling and experimental modelling and their current state of the art is discussed. One of the major gaps remaining is the lack of basic thermodynamical and kinetic data at relevant temperature and pressure conditions for each of these four application domains. Real challenges are the coupled solute transport and geomechanical modelling, the modelling of impurities in the CO₂ stream and pore-scale modelling applications.