大气污染物浓度的投影寻踪自回归预测

环境污染预测是环境科学研究的重要课题之一。线性回归预测，时序预测和灰色ＧＭ预测是常用的大气污染预测方法，但始终未有摆脱“假定－模拟－预报”的模式束缚，难以适应非正态，非线性分布的客观内在规律，投影寻踪高新技术，对数据结构或特征不作任何假定，而是通过直接审视和分析数据，应用计算机软件程序设计，为时序分析开辟了一条“审视数据－模拟－预报”的数据分析新途径，该文采用投影寻踪自回归新技术，建立了大气污染物     

华东地区空中SO2负荷量与地面SO2浓度的相关性

通过华东地区地面ＳＯ２深度和空中ＳＯ２负荷量的同步实测数据，证明了两者有较好的相关性、相关系数达０．９１；并建立了两者之间的线性方程，用方程计算的结果与实测结果比较，评判在±２０％以内。计算结果与实测结果无显著性差异。     

大气化学仪器测量进展

从平流层和对流层的大气化学过程入手，分析了研究各个反应所采用的测量手段；从当前大气化学的发展要求提出了理论研究和模式建立中对仪器测量手段的要求。并且从测量坪台这一角度分析了目前在大气化学领域使用的主要测量仪器和手段。     

氮氧化物污染防治技术进展

氮氧化物 (NOx)是主要的大气污染物之一 ,NOx的治理历来受到国内外研究人员的重视。本文扼要介绍了国内外近 1 0几年来 NOx防治技术的研究进展     

重庆城区大气悬浮颗粒物（TSP）金属元素特征

分析了重庆城区１９９２年三个采样点（市中区、江北区、大渡口区）大气环境ＴＳＰ中１０种金属元素浓度，结果表明：三个采样点之间及不同季节，金属元素浓度分布存在差异；重庆城区大气ＴＳＰ中金属元素浓度高于北京、上海等城市，并探讨了产生的原因。     

Unidirectional gas flow in soil porosity resulting from barometric pressure cycles

During numerical simulation of air flow in the vadose zone, it was noticed that a small sinusoidal pressure would cause a gradual one-way migration of the pore gas. This was found to be a physical phenomenon, not a numerical artifact of the finite element simulation. The one-way migration occurs because the atmospheric pressure, and hence the air density, is slightly greater when air is flowing into the ground than when air is flowing out of the ground. A simple analytic theory of the phenomenon is presented, together with analytic calculations using actual barometric pressure data. In soil of one Darcy permeability, the one-way migration is of the order of a few tenths of a meter per year for either plane flow from ground surface or for radial flow from an open borehole. The migration is sufficiently small that it will have no practical consequences in most circumstances; however, investigators who conduct detailed numerical modeling should recognize that this phenomenon is not a numerical artifact in an apparently linear system.     

GIS技术在城区大气降尘污染分区评价中的应用

应用地理信息系统（ＧＩＳ）技术分析了焦作市城区大气降尘污染状况。根据１９９５年城区降尘实测数据,绘制了降尘量等值线图,分析了城区降尘污染持的空间分布特征,引入降尘污染指数,将降尘污染程度做了六级划分,并利用ＡＲＣ／ＩＮＦＯ软件进行图像处理,生成拓扑关系,从而对焦作城区降尘污染程度进行了分区和评价。     

Photochemical production of ozone and control strategy for Southern Taiwan

An observation-based method (OBM) is developed to evaluate the ozone (O₃) production efficiency (O₃ molecules produced per NO_x molecule consumed) and O₃ production rate (P(O₃)) during a field campaign in southern Taiwan. The method can also provide an estimate of the concentration of OH. A key step in the method is to use observed concentrations of two aromatic hydrocarbons, namely ethylbenzene and m,p-xylene, to estimate the degree of photochemical processing and amounts of photochemically consumed NO_x and NMHCs by OH. In addition, total oxidant (O₃+NO₂) instead of O₃ itself turns out to be very useful for representing ozone production in the OBM approach. The average O₃ production efficiency during the field campaign in Fall (2003) is found to be about 10.2±3.9. The relationship of P(O₃) with NO_x is examined and compared with a one-dimensional (1D) photochemical model. Values of P(O₃) derived from the OBM are slightly lower than those calculated in the 1D model. However, OH concentrations estimated by the OBM are about a factor of 2 lower than the 1D model. Fresh emissions, which affect the degree of photochemical processing appear to be a major cause of the underestimate. We have developed a three-dimensional (3D) OBM O₃ production diagram that resembles the EKMA ozone isopleth diagram to study the relationship of the total oxidant versus O₃ precursors. The 3D OBM O₃ production diagram suggests that reducing emissions of NMHCs are more effective in controlling O₃ than reducing NO_x. However, significant uncertainties remain in the OBM, and considerable more work is required to minimize these uncertainties before a definitive control strategy can be reached. The observation-based approach provides a good alternative to measuring peroxy radicals for evaluating the production of O₃ and formulating O₃ control strategy in urban and suburban environments.     

The Modelling of Turbulence from Traffic in Urban Dispersion Models — Part I: Theoretical Considerations

The modelling of pollutant dispersion at the street scale in an urban environment requires the knowledge of turbulence generated by the traffic motion in streets. In this paper, a theoretical framework to estimate mechanical turbulence induced by traffic in street canyons at low wind speed conditions is established. The standard deviation of the velocity fluctuations is adopted as a measure of traffic-produced turbulence (TPT). Based on the balance between turbulent kinetic energy production and dissipation, three different parameterisations for TPT suitable for different traffic flow conditions are derived and discussed. These formulae rely on the calculations of constants that need to be estimated on the basis of experimental data. One such estimate has been made with the help of a wind tunnel data set corresponding to intermediate traffic densities, which is the most common regime, with interacting vehicle wakes.     

Characteristics of Resuspension,Settling and Diffusion of Particulate Matter in a Water Column

Experiments were conducted in order to characterize the distributions of concentrations of suspended particulate matter (SPM) in water columns of lakes and reservoirs. The experiments, in a reduced model of the water column, used a set of oscillating grids. Runs were done with particles denser than water as well as with light particles. The results were in good agreement with analytical solutions for steady-state, and non-steady-state conditions. An approximate analytical solution was derived and found to be in agreement with the full solution. The threshold for resuspension was measured, and characterized in terms of a modified Shields parameter, which is appropriate to a zero-shear environment. All experiments showed that the distribution of SPM exhibited a layer near the bottom that is thought to be analogous to the benthic nepheloid layer (BNL) observed in larger lakes. The thickness of the nepheloid layer increases with the turbulence intensity.