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 method for predicting odor frequencies from a point source.
Abstract It is demonstrated that a fluctuating plume dispersion model can be used to give realistic estimates of odour frequencies around a point source, when the odour threshold of the chimney gases is determined by sensory methods ( Lindvall , 1970). The theoretical calculations are compared with observational results from a field experiment at and around a sulphate pulp factory in Sweden. Trained observers were used, making a large number of instantaneous observations of odour in the outdoor air at a variety of locations around the factory.
The Russian language maintenance and language contacts
In our introductory article, we outline the main sociolinguistic features of Russian as a heritage language of post-Soviet immigrants in European settings and beyond. We offer a general overview of the evolution of Russian as a global language, with a particular focus on its geodemographics and economic and social value as a lingua franca . Based on this, we analyse the main principles defining the maintenance of Russian as a language of migration and as a heritage language in different countries, and emphasise the most important questions that still need to be addressed in this field of research. The main objective of this special issue is to combine the most recent research on the vitality of different languages of post-Soviet republics in new political milieu, with a particular focus on European and Asian countries, but there are other objectives as well. We propose to explore the factors that have either favoured or hindered the maintenance and transmission of languages of post-Soviet immigrants and repatriates, and how these sociolinguistic processes become evident in language vitality on both private and public levels. Our special issue primarily addresses the questions of family language policy, new language contacts and their management, and linguistic landscape in heritage speakers, diasporas and their new settings in Europe, Asia and the US.