Global awareness of air emissions in manufacturing and the effect of emissions on the environment resulted in regulation of industry in most developed countries over the last two decades. Regulatory development continues beyond these initial "first tier" efforts with evolving regulations based in part on toxicity models which involve additive effects of individual pollutants.

Thermal analysis methods have been employed in developing a fundamental understanding of the release of "first tier" pollutants in manufacturing of traditional ceramics. Aside from particulate matter, the pollutants of most interest have been sulfur oxides or "SOx", hydrogen fluoride or HF, and hydrogen chloride or HCl. In the cases of SOx and HF, evolved gas analysis using FT-IR revealed that there are two regimes of release of the acid gas species. There is a low temperature region of release for SOx in the range of 400-525^oC and a low temperature release for HF in the area of 450-800^oC. The high temperature release for both SOx and HF occurs above 900^oC due to desorption processes.

The next decade will likely include a refinement of "first tier" regulations, and new "second tier" regulations are expected. Both of these possibilities could require investigation of volatile organic compounds emitted during the preheating stage of firing of ceramics. The key questions include:

• What species are present in the exhaust gases, i.e. are they discrete compounds or are they molecular fragments?
• How do process parameters such as temperature, residence time, and atmosphere affect the type and quantity of organic species present in the exhaust?

The correct identification of species is of critical importance given the new methods of environmental toxicology assessment. It is anticipated that coupled thermal analysis and evolved gas analysis will be the most convenient way of investigating these emerging problems.

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