Causes for emissions

Sources for volatile substances in indoor air are diverse and originate, apart from that brought in with outside air and produced by die hving occupants (people, pets) and their activities (e.g., smoking), from the materials fliemselves which have been applied for building and furnishing the room. These include  

These materials may contain volatile organic, but also inorganic, compounds, which are evaporated during use. The emission of these volatile compounds is influenced by a large number of factors, such as  

The residual monomers from plastics, reactive products (e.g., formaldehyde), degradation products, flame protection media, softeners etc. may be emitted from building materials. 

A substantial part of emitted materials are solvents. They preferably originate from varnishes, paints and glues. Table 18.1.1 shows a survey of the main types of varnishes referring to their average solvent content. 

Despite the introduction of water based and powder varnishes, celltdose nitrate varnishes with their high solvent content, are stUl widely used due to their easy application and their low prices. The current varnish application still requires the use of solvents. The chosen coating procedure determines the necessary processing viseosity, which may be adjusted in different ways  

---

REVIEW OF SOURCES OF SOLVENT EMISSIONS 17.1.2.1 Causes for emissions... 

With respect to fuels utilized as heating fuels for industrial furnaces, or as motor fuels for large diesel engines such as those in ships or power generation sets, the characteristics of primary importance are viscosity, sulfur content and the content of extremely heavy materials (asphaltenes) whose combustion can cause high emissions of particulates which are incompatible with antipollution legislation. 

Trichloroethylene use has declined as a result of environmental concerns. However, trichloroethylene may replace some 1,1,1-trichloroethane appHcations. Perchloroethylene used in small businesses for dry cleaning will be regulated for emissions under the same guidelines as those that govern the large chemical producers. This will cause replacement of perchloroethylene for those appHcations where recovery is uneconomical. Methylene chloride has been classified as a suspected carcinogen and its use will decline in aerosol and paint stripping appHcations because of health concerns. 

One of the reasons the tribes of early history were nomadic was to move periodically away from the stench of the animal, vegetable, and human wastes they generated. When the tribesmen learned to use fire, they used it for millennia in a way that filled the air inside their living quarters with the products of incomplete combustion. Examples of this can still be seen today in some of fhe more primitive parts of the world. After its invention, the chimney removed the combustion products and cooking smells from the living quarters, but for centuries the open fire in the fireplace caused its emission to be smoky. In ad 61 the Roman philosopher Seneca reported thus on conditions in Rome ... 

VISCREEN is an initial screening model for visual impact caused by emissions to the atmosphere. Click the filename to download the file. 

In a strong electric field, a free electron acquires enough kinetic energy to cause an impact ionization i.e., an electron impacting on a neutral molecule causes an emission of a new electron, leading to the formation of new electron-ion pair. The new free electron is, in turn, accelerated to a velocity sufficient to cause further ionization. This leads to an avalanche-type generation of free electrons and ions. The electric field provides the necessary energy in such a way that the process can continue without the external radiation which was necessary for the onset of the process. 

All of the luciferases cause the emission of a bluish light when they catalyze the oxidation of coelenterazine. However, there are some marked differences between the decapod shrimp luciferases and the cnidarian luciferases (Matthews et al., 1977a,b). For example, the luminescence caused by the former (Amax about 452 nm) is bluer than that caused by the latter (7max 470-480 nm), and the optimum pH of the former, about 8.5, is significantly higher than that of the latter (Renilla, 7.4 Ptilosarcus, 7.0). The optimum temperature of the decapod shrimp luciferases (35°C) is higher than those of Ptilosarcus (23°C) and Renilla (32°C). 

So far, we have discussed only the detection of y-rays transmitted through the Mossbauer absorber. However, the Mossbauer effect can also be established by recording scattered radiation that is emitted by the absorber nuclei upon de-excitation after resonant y-absorption. The decay of the excited nuclear state proceeds for Fe predominantly by internal conversion and emission of a conversion electron from the K-shell ( 90%). This event is followed by the emission of an additional (mostly Ka) X-ray or an Auger electron when the vacancy in the K shell is filled again. Alternatively, the direct transition of the resonantly excited nucleus causes re-emission of a y-photon (14.4 keV). 

The major cause for the 38% increase in C02 was a more than doubling of the coal use in electric utilities and a near doubling of coal use in industrial use. The energy efficiency path still increased C02 production to 1.5 billion metric tons per year. The high-efficiency case does use less coal. Other energy studies predict a decline in energy-growth rates and a decline instead of an increase in C02 emissions. 

With this technique, under an especially equipped electron microscope, high-energy electrons are focused on a fine probe and directed at the point of interest in the specimen. The electrons interacting with the sample atoms cause the emission of the characteristic X-rays, which are detected and identified for qualitative analysis and used, generally through suitable standardization, to perform also a quantitative analysis. 

From the above one might be tempted to attribute ultrasonically enhanced chemical reactivity mainly to the mechanical effects of sonication. However this cannot be the whole reason for the effect of ultrasound on reactivity because there are a variety of homogeneous reactions which are also affected by ultrasonic irradiation. How, for example, can we explain the way in which power ultrasound can cause the emission of light from sonicated water (sonoluminescence), the fragmentation of liquid alkanes, the liberation of iodine from aqueous potassium iodide or the acceleration of homogeneous solvolysis reactions ... 

Mechanical processing (e.g., abrasion) of metallic surfaces causes the emission of electrons this is known as the Kramer effect (Kramer 1950). The effect has been shown by the measurement of selfgenerated voltages between two metallic surfaces under boundary lubrication (Anderson et al. 1969, Adams and Foley 1975). The exoelectrons have a kinetic energy from 1 to 4 eV (Kobzev 1962) and they may initiate some chemical reactions. For instance, if the metal (whose surface has been worked) is placed in an aqueous solution of acrylonitrile, the latter forms an abundant amount of an insoluble... 

---