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951.
M. Griggs 《Journal of the Air & Waste Management Association (1995)》2013,63(5):356-358
In recent years there has been considerable use of optical observations to determine the aerosol mass loading of the atmosphere. Nephelometer measurements of the scattering coefficient have been used for the local volume mass loading, and the turbidity of the atmosphere determined by the Volz sun photometer has been related to the vertical mass loading. This paper analyses various approaches to measuring the mass loading, and presents improved relationships between the optical observations and the aerosol mass loading. 相似文献
952.
Jean P. Paré M.Sc 《Journal of the Air & Waste Management Association (1995)》2013,63(6):325-327
The lead acetate paper tape reagent method for the estimation of hydrogen sulfide in air has been reviewed with the conclusions that the colored spots on which the quantitative estimation is based are not stable and do not lend by themselves to accurate results. Although it may be retained for grab sampling work, the lead acetate paper tape reagent is not acceptable as a stoichiometric reagent in any case where long duration sampling periods are concerned like in air pollution studies. A new mercuric chloride paper tape reagent has been developed as a substitute. Due to the fact that the colored spots resulting from the action of hydrogen sulfide on mercuric chloride are sensitive and very stablet, this new paper tape reagent is proposed as an adequate and reliable analytical too for the estimation of hydrogen sulfide in air. Also, a more comprehensive application of the paper tape analytical system is proposed throughout a suitable control of the factor tape retention capacity vs sampling rate which imposes some restrictions in the selection of the practical working range of concentrations. Nevertheless this working range is still wide enough to encompass all the hydrogen sulfide concentrations normally encountered in the city atmosphere. 相似文献
953.
954.
955.
John M. Pierrard 《Journal of the Air & Waste Management Association (1995)》2013,63(9):632-637
The role of particulate matter and oxides of sulfur in degradation of the atmospheric environment is discussed. The Federal Air Quality Criteria for these pollutants are analyzed for their conformance with the requirement of the Clean Air Act of 1967 that they reflect the latest scientific knowledge pertinent to the indication of their effects on health and welfare. Visibility reduction by suspended particulate matter is treated and the bases for the criteria issued in the documents “Air Quality Criteria for Particulate Matter” and “Air Quality Criteria for Sulfur Oxides” are examined. The reactions between particulate matter and gaseous pollutants are discussed, along with the Impact of particulate matter on modifications of weather processes. Local effects, such as precipitation, are considered. The relationship between pollution by particulate matter and cloud formation is discussed, as are persistence of fog and the observation that certain sources of particulate pollution are also sources of ice nuclei. 相似文献
956.
C. M. Peterson H. J. Paulus G. H. Foley 《Journal of the Air & Waste Management Association (1995)》2013,63(10):795-801
Instruments capable of measuring in situ numbers of particles within specific size ranges covering a particle-diameter spectrum of approximately 0.001 – 10 microns have been employed to continuously monitor the concentration and size-distribution of atmospheric aerosols. The monitoring site was a television tower located on the boundary between Minneapolis and St. Paul, Minnesota. Air samples were drawn from 70, 170, and 500 feet above ground level and analyzed with optical, electrical, and condensation particle counters to obtain a number-size distribution within the 0.001 – 10 micron size range. In addition to the measurement of particle number and size, several micrometeorological parameters were simultaneously monitored. Particle number-size distributions which were measured during periods of temperature inversion are reported 相似文献
957.
M. Boulerice W. Brabant 《Journal of the Air & Waste Management Association (1995)》2013,63(6):432-434
Since 1966, the Division of Laboratories of the Department of Health of the City of Montreal is carrying on measurements of gaseous pollutants. In order to efficiently use the technical staff that our administrators wanted to devote to the fight against air pollution, a new lead dioxide support for the determination of sulfur dioxide has been devised. The preparation of candies according to the standard method requires much time and skill from the operator, whereas the technique that is proposed is rapid, easy, and provides plates of a high degree of uniformity. A technician with little experience can coat a great number of plates per day with no difficulty. N. A. Huey working at the National Center for Air Pollution Control in Cincinnati published in the September 1968 issue of this Journal a new technique which consists of coating the inside of a plastic Petri dish with a PbO2 paste. His method also has the above mentioned advantages. The plates that are suggested allow a simplification of the preliminary work for several types of analyses such as gra-vimetry,1 colorimetry,3 turbidimetry,4,5 titrimetry,6 and nephelemetry.8 相似文献
958.
959.
Jesse H. Bennett A. Clyde Hill David M. Gates 《Journal of the Air & Waste Management Association (1995)》2013,63(11):957-962
A model simulating pollutant exchange with isolated leaves that integrates factors which have been found to be important in regulating pollutant uptake by leaves is presented. The model is patterned after an electrical analogue simulator and was designed to emphasize the effects of pollutant and leaf properties on the process. The article discusses the relative significance of factors affecting gas transfer, sorption of pollutants by leaf surfaces, and pollutant solubility and fate on the uptake process. Data is presented showing uptake of ozone by exposed mesophyll and several epidermal surfaces chosen for their different surface characteristics. The model was used to derive a mathematical expression for the exchange process which was rearranged to define internal (average) pollutant solute concentration in terms of external concentration, leaf and boundary layer diffusion resistance, surface sorption and pollutant solubility. The importance of estimating internal solute concentration is discussed. 相似文献
960.
J.M. Heuss G.J. Nebel J.M. Colucci 《Journal of the Air & Waste Management Association (1995)》2013,63(9):535-548
The recently promulgated national air quality standards for carbon monoxide, nitrogen dioxide, hydrocarbons, and photochemical oxidant are critically reviewed.This review indicates that the standards are more restrictive than can be supported by available data. 相似文献