Emissions nuisances

During the manufacture of glass, considerable dust, with particles averaging about 300 /xm in size, will be emitted. Some dusts may also be emitted from the handling of the raw materials involved. Control of this dust to prevent a nuisance problem outside the plant is a necessity. When glass is blown or formed into the finished product, smoke and gases can be released from the contact of the molten glass with lubricated molds. These emissions are quite dense but of a relatively short duration. 

The major effect of such open burning is the nuisance caused by the smoke, but health effects are noticed by sensitive individuals downwind from the bum. Table 30-18 lists the pollutant emissions from grass field burning (15). 

Listing gaseous emissions, concentrations, smoke characteristics prevailing winds and exposed zones toxicity or nuisance potential effects of synergism or poor atmospheric dispersing conditions. Consent limits. 

The effects of transport on economy, people and on the environment are manifold. They include the consequences of transport accidents and fatalities, nuisance and health effects caused by steady noise exposure, air emissions and the exhaust and resuspension of particles, climate impacts by the emission of greenhouse gases, soil and water contamination, and the deterioration of natural habitats. Moreover, the financial burden of infrastructure provision and the additional travel and production costs caused by congestion should be mentioned but these items are mainly borne by transport users themselves and thus are only partly imposed on society as a whole. Not all of these effects are equally relevant for all means of transport. While accidents constitute the major problem of car travel, the railways definitely face a noise problem and air transport contributes most to the emission of climate gases. 

In this paper attention is paid to the ammonia emission from slurry as such. There are more and more indications that this emissions cause considerable damage to the environment, being possibly more important than the nuisance of bad smells. 

Another application is the prediction of the effectiveness of changes in the emission source configuration, in order to reduce the odour nuisance in the existent vicinity. That could help to avoid expensive misinvestments. 

Fig. 1. Emission-Transmission-Immission of airbom pollutants. Quelle=source, Luftbewegung=atmospheric flow, Verdunnung= dilution, Belastigung=nuisance.

The chimney, originally devised to increase draught through fires and to provide smoke extraction, has found extensive use in many industries to aid the dispersion of odour. The extra height gained by the point of emission is frequently enough to give the extra dilution required to reduce the risk of odour nuisance at even relatively nearby properties. 

The actual scope and limitations of chemical analysis of odour show that all problems can be tackled as far as emission is concerned. For immission measurements some progress is necessary, but there is no essential reason why chemical analysis would be unable to attain the desired sensitivity for all types of odorants. There is no doubt that in a few years the last difficulties will be solved. In order to achieve real control of odour nuisance, automatic measurement is necessary on a long time basis. There again some technical development is to be expected. 

Water Reclamation Works by their very nature can, at times be the source of unpleasant odorous emission. The odour-intensive compounds (osmogenes) which make up these emissions are believed to arise mainly as the decomposition products of carbohydrates and proteins. The breakdown of this waste material proceeds by aerobic and anaerobic processes at various stages of the treatment plant. Atmospheric pollution of this nature frequently results in complaints from members of the public either resident, or perhaps employed in the vicinity of such works. In order to confirm or deny that a reclamation works is responsible for a particular nuisance and, if possible to identify the causal agents it was decided that the Authority should have the capability of analysing for odorous and other polluting constituents of the atmosphere. This paper describes the progress made towards this objective and summarises the experience gained with a procedure in use. There are two principle approaches available for the analytical classification of odorous emissions -... 

When comparing the dust-borne concentrations of butyric acid and p-cresol with the odour thresholds it seems that the concentrations are too small to be relevant for an odour nuisance. However, if the dust is removed from the gas phase of the air from animal houses the odour disappears (39), (40), (14). This supports the opinion of HAMMOND et al. (40) that the odor is concentrated on the dust particles. The authors conclude from their data that the concentration of the two odorants butyric acid and p-cresol is about 4TO7 greater on an aerosol particle than it is in an equal volume of air. Thus, an aerosol particle deposited on the olfactory organ carries odour equivalent to a much greater volume of air (40). These considerations indicate that dust from animal houses should be taken into account in connection with odour emission/immission measurements not only by chemical analysis but by sensory evaluations using olfactometers without dustfilters, as well. 

The modification of silica gel with diethanolamine (DEA) resulted in a stable alkaline filter, capable to collect H2S, COS, CS2, S02, C02 and H20 from contaminated air.56 The presence of odorous mercaptanes and organic sulphides may be selectively determined, as these compounds do not react with the DEA and therefore are not collected on the filter. By means of this scrubber an automatic survey system has been developed allowing the detection and determination of the nature of odour nuisance, caused by industrial emissions of volatile organic sulphur compounds, up to the ppb-level. The system consists of two continuous, highly sensitive and fast responding sulphur analyzers. One of the detectors is equipped with an SO, scrubber and measures the total amount of non-S02 sulphur compounds. The other detects the organic S-compounds, using the amine-silica filter. 

It should not be supposed that crystal defects enter into the picture only as nuisances which the chemist seeks to avoid or eliminate. Actually, certain optical and electrical properties of oxides, sulfides, and halides have been found to depend strongly on the nature and extent of crystal defects. Indeed, semiconductivity, fluorescence (absorption of radiation and emission of less energetic radiation), and phosphorescence (delayed fluorescence) of some salts may be spectacularly increased, not only by a small stoichiometric excess of one of the constituents, but also by addition of very tiny quantities of a foreign ion. Perhaps the best known example is the case of zinc sulfide which, when precipitated from aqueous solution and dried at low temperatures, shows negligible fluorescence upon exposure to ultraviolet light. When the sulfide is heated to... 

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