Table 1 presents the basic information for the six plants and characteristics of the end products (tiles). Figure S1 (Supporting Information) schematically illustrates one of these kilns. Emission of dioxins may occur during preheating and cooling of tiles in the firing process. The tiles were subjected to the standard thermal cycles used at the plants where the tests were carried out, with total firing times (cold to cold) of 55−70
min, and peak firing temperatures of about 1200−1300 °C. To estimate the emission contribution, the gas samples after the gas purification system were simultaneously collected from preheating and firing zone stack and cooling zone stack. The
details of gas sampling are list in Table 1.