appendix b emissions modeling introduction this provides additional details of the methodologies used to estimate control and no scenario results obtained by these methods methodological information are provided for each six principal emission sec tors industrial combustion processes elec tric utilities on highway vehicles off ve hicles commercial residential sources initial section assesses projections presented in analysis 1 comparing 1970 1990 projec tions with recent epa trends report estimates same years 2 trend 1950 as reported first compari son indicates that approximate but do not precisely match data reason mismatch is discussed below second comparison useful demon strating pre would pro vide a satisfactory basis extrapolating into period inability simply extrapolate further justification applying present meth odologies generate
