DETERMINATION OF ODOR SOURCES FOR CONTROL
The successful solution of odor pollution problems first requires an assessment of the nature and extent of the problems. A plant or facility that emits odor from a single source (such as ii stack or vent) requires less effort than a plant with a variety of odor sources that may number in the hundreds. In the latter case, there is a need to assess the problem in such terms as to achieve maximum reduction in odor at a minimal control cost. Quantitative and accurate measurements of the various emission sources and their contribution to the odor in the ambient air must be determined in order to identify and rank the various sources that should receive priority for control. Accurate measurements of odor strength relative to concentration are also useful for defining the degree of control necessary for the single-source situation. Attempts to relate source odor measurements with ambient odors by the use of diffusion equations have met with varying degrees of success.1.2 Wohlers,l utilizing an evacuated bulb technique for sampling stack gases from a petroleum coking plant, a kralt paper mill, an anion-garlic dehydrating plant, and a rotogravure printing plant, found that odor measurements at the stacks did not agree in all cases with the calculated dilutions at the distances in the field where the odors were noted. Hogstrom2 demonstrated that a fluctuating plume dispersion model can be used to give realistic estimates of odor frequencies around a point source when the odor thresholds of the chimney gases (sulphate pulp factory) are determined by sampling and sensory methods described by Lindvall.3 Our experience in sampling and evaluating odors has indicated that existing sampling techniques such as ASTM syringe method have seriously underestimated the magnitude of odors emitted by a factor in the range of 2OO-2O,OOO.4 We believe that inadequate sampling and evaluation techniques are the major reasons for reported “failures” of dispersion estimates in predicting ambient odors. In our technique, we use trained odor chemists to carry out odor surveys of the surrounding areas to define the odor types and intensities perceived off-site and to conduct in-plant surveys to identify all significant odor sources. T o supplement this, we have developed a source-sampling detailed laboratory odor-evaluation technique to allow comparison of the various odor sources and to make use of predictions based on dispersion equations. We have observed reasonably good correlation between predicted odor intensities from the source analyses determined in the laboratory and those observed by our analysts in the field. OFF-SITE SURVEY
A critical review of regulations for the control of odors.
ISSN: 0002-2470 (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/uawm16 a critical review of Regulations for the Control Of Odors Gregory Leonardos To cite this article: Gregory Leonardos (1974) a critical review of Regulations for the Control Of Odors, Journal of the Air Pollution Control Association, 24:5, 456-468, DOI: 10.1080/00022470.1974.10469933 To link to this article: https://doi.org/10.1080/00022470.1974.10469933
An experimental study on atmospheric diffusion
A method has been devised by which atmospheric diffusion can be studied over a few kilometres range with rather good precision at only moderate expense. The method which is based on smoke puff photography is especially well suited for thermally stable conditions. It is possible to study the effect of both the low frequency part and the high frequency part of the Lagrangian spectrum of turbulence on the diffusion. More than 100 complete experiments have been performed at two places in Sweden at three different levels of release. The vertical standard deviation of matter is found to be a function of the following stability parameter: ( ∂ θ ∂ z)/u 2 f , where ∂ θ ∂z is the local vertical gradient of potential temperature, and u z f is “the free wind”, that is the wind just above the friction layer. A comprehensive formula, or rather a system of formulae, for the variation of the vertical standard deviation (sampling time about one hour) with distance from the source, stability and height above the ground of the point of release, has been developed. The formulae are believed to have a very general application, the only site parameter being necessary to know is the roughness length, z 0 . The formulae have been successfully tested against results from various tracer experiments described in the literature. The variance of the horizontal distribution of matter for one hour sampling time is found to be the sum of two parts: one which is independent of stability and one which is dependent on stability in much the same way as is the vertical variance. The distribution of matter from a ground level release is described by new formulae. The result is in good agreement with experimental and theoretical evidence in the literature. DOI: 10.1111/j.2153-3490.1964.tb00162.x