“…Due to the different reaction stages in MWIs, until now no clear-cut relations between normal operating conditions of various MWIs and their PCDD (and/or PCDF) content of effluent gas flows have been found (6,7). Only a limited number of testing programs with extreme operating conditions have revealed a correlation between CO emissions and PCDD/PCDF effluent gas contents as well as a relationship between operating temperature and PCDD/ PCDF emissions (8,9).…”