national air pollutant emission trends 1900 1998 united states office of quality epa 454 r 00 002 environmental protection planning and standards march 2000 agency research triangle park nc 27711 u s the working together for cleaner ii disclaimer this repor t has been reviewed by st an dards mention trade names or commercial products does not constitute endorsement recommenda tion use foreword iii eword document presents most recent estimates emissions criteria pollutants each are estimated many dif ferent source categories which collectively account all anthropogenic report total from 50 ep a region in country these updated annually tracks changes since passage clean act amendments 1990 net ef fect factors including nation economy industrial activity technology consumption fuels traf fic other activities that cause pollution also reflect
