Some Applications of Microscopy to Air Pollution

The microscope as it has been and is now applied to air pollution work is discussed. A summary of the most common particulate sampling equipment is presented and distinctions as to the area of usage (suspended, or settled particulates) are made in each instance. Actual cases are discussed in which the polarizing microscope was used to determine identities and source of particulate pollutants. Particles from such sources as power plants, feed mills, and combustion sources are discussed and photomicrographs of known samples and unknown particles causing complaints are presented and compared as part of the discussion. References are given which deal with sampling equipment and microscopic analysis of various particulates.     

TiO2光催化氧化技术在环境治理中的应用

TiO2光催化氧化技术是一种新型现代环境污染治理技术,它具有节能、高效、稳定和环保的特点,应用前景广阔.文中对TiO2光催化氧化机理、在环境污染治理中应用及在应用中应当解决的问题进行了论述.     

Air Pollution Research Problems

The TR-l Research Committee of the Air Pollution Control Association conducted a survey during 1969–70 to determine what air pollution research problems require attention. All APCA committees were requested to contribute topics to this survey, especially within their area of activity. Other professional societies were contacted through liaison representatives of APCA. The responses to the survey have been reviewed, categorized, selected, and edited for inclusion in this report. Additional material and concepts have been contributed by members of the TR-l Committee.     

Problems of Relating Atmospheric Analyses to Effects of Air Pollution on Agriculture

Relating of air pollution concentrations to effects on agriculture is hampered by deficiencies in present methods of atmospheric analysis and by inadequate knowledge about how various factors modify the effects. Analytical methods frequently lack sufficient sensitivity or specificity to determine accurately the substances involved. Typical examples include the difficulty of distinguishing among fluoride compounds with loidely differing phytotoxic activity, the serious interference from concomitant air pollutants with the usual methods of determining ozone, and the common failure or inability to detect short interval concentration extremes which may cause acute injury. The interrelationship of pollutant concentration and length of exposure in determining plant injury is poorly understood, as are the modifying effects of environmental conditions and age of tissue. The identity of some of the phytotoxic components of the urban photochemical pollution complex is still uncertain, making it difficult to select appropriate analytical methods. Caution should be exercised in using atmospheric analysis data to predict effects of air pollution on agriculture until these deficiencies in analytical methods and understanding of the problem are overcome.     

Air Pollution Problems of the Steel Industry

Urban air pollution has traditionally been modeled using annual, or at best, seasonal emissions inventories and climatology. These averaging techniques may introduce uncertainty into the analysis, if specific emissions (e.g. SO₂) are correlated with dispersion factors on a short-term basis. This may well be the case for space heating emissions. An analysis of this problem, using hourly climatological and residential emission estimates for six U.S. cities, indicates that the errors introduced using such averages are modest (~ ± 12%) for annual average concentrations. Maximum hourly concentrations vary considerably more, since maximum heat demand and worst case dispersion are in general not coincident. The paper thus provides a basis for estimating more realistic air pollution Impacts due to residential space heating.     

Lidar Applications in Air Pollution Research and Control

The fundamental capabilities and limitations of the lidar (laser radar) in observing particulate concentrations in the atmosphere are discussed. The advantages of the lidar technique stem from its ability to obtain measurements remotely and at a high density in space and time. The quantitative application of the technique is limited by the accuracies with which: (1) the separate effects upon the return signal of back-scatter and attenuation may be identified; and (2) the optical parameters may be related to the characteristics of the aerosol. The main areas of utility for lidar in air pollution research and control are: (1) to observe the structure and height of mixing layers; (2) to measure the transport and diffusion of plumes or clouds of particulates; and (3) to remotely determine smoke-plume opacity. These applications are briefly reviewed and exemplified.     

Interregional Exchanges of Air Pollution: Model Types and Applications

Regional scale air quality simulation models covering spatial scales of thousands of kilometers are finding increasing applications in studies of acid deposition and other air pollution problems. The purpose of this paper is to familiarize the nonexpert with the characteristics of the major types of interregional air quality models currently in use: Eulerian grid, statistical trajectory, and Lagrangian trajectory. The basic features, advantages, and disadvantages of each of these modeling approaches are summarized, as are the important limitations and problems associated with interregional modeling in general. Typical applications are illustrated using examples from the use of a representative Lagrangian trajectory model, ENAMAP, over the eastern North American area.     

Analytical Problems Posed by Pollution by Fluorine Compounds

The author sets forth the analytical problems posed by fluoride pollution and makes a critical study of the methods which are being used. He reports on the results that have been discovered over several years of investigation.     

Improvement of Ambient Sulfur Dioxide Concentrations by Conversion from Low to High Stacks

A study of the “before” and “after” ground-level S0₂ concentrations near the Muskingum River Plant of the American Electric Power System shows that the conversion from low to high stacks has accomplished marked reductions in ambient concentrations. These reductions are in reasonable agreement with theoretical calculations and are most apparent within 5 km of the source. EPA Standards are now being met in this area despite the presence of the 1440 MW power plant burning 5% sulfur fuel with no treatment of the stack gas.     

Informative Air Pollution Problems in Fly Ash Sintering Plant

A long-term field and laboratory program designed to determine and understand the effects of air pollutants on the performance of electric contact materials has reached the one-year mark. An extensive variety of metals has been exposed at six field environments, for periods up to one year (August 1963 to August 1964). These environments were selected to provide a wide range of air pollutants in typical data processing or process control situations. The program undertakes to determine material degradation as a function of time and environment. The important air pollutants at the field sites are measured regularly, and materials are returned periodically to the laboratory for evaluation using techniques developed specifically for this program. The results of the program to date are presented, and preliminary correlations are drawn.     

Some Air Pollution Problems Associated with Agriculture in Texas

A report of some experiences with air pollution problems associated with the cotton ginning industry and the application of agricultural insecticides and herbicides.     

Ecosystem Services in Urban Landscapes: Practical Applications and Governance Implications

Urban landscapes are the everyday environment for the majority of the global population, and almost 80 % of the Europeans live in urban areas. The continuous growth in the number and size of urban areas along with an increasing demand on resources and energy poses great challenges for ensuring human welfare in cities while preventing an increasing loss of biodiversity. The understanding of how urban ecosystems function, provide goods and services for urban dwellers; and how they change and what allows and limits their performance can add to the understanding of ecosystem change and governance in general in an ever more human-dominated world. This Special Issue aims at bridging the knowledge gap among urbanization, demand creation, and provisioning of ecosystem services in urban regions on the one hand and schemes of urban governance and planning on the other.