Document jOqwreJzea0RKEmVeVv45OON

Total particulate from automobile exhaust ~ 0.J5 g/mile or ~ 5 g/gallon of fuel consumed Total particulate from diesel exhaust ~ 50 g/gallon of fuel consumed The level of emissions depends on fuel composition, engine design, operating conditions, and other variables. Gasoline-engine exhaust particulate contains the following (if leaded fuel is u6ed):' Pb (mostly in compounds ) 20 to 40$ ' Carbon particles and various organic com pounds, including raw or partially burned lubricating oil - variable 40$ Compounds of Ca and Mg ~ 2$> Cl and Br (in Pb compounds mostly) - 15 to 50 Sulfur (largely as sulfate) - up to a few Fe and Fe oxides - a few <$, Zn - a few tenths <f> Al, Si, Cu - traces The'Pb, Cl, and Br are present by virtue of the tetra-ethyl lead together with the ethylene chloride and bromide added to scavenge the lead. Lead compounds that have been reported include PbclBr, NH4Cl(PbCLBr)2, (NKjC1)2 PbciBr, [PhstPO^glsPbClBr if phosphorus additives are present, PbS04, and Pb0*PbS04 (see Refs. 4, 25, JO, Jl, J2, J6). The lead halides form by condensation from the vapor phase as the cooling exhaust ga6 reaches the J50C range. The Mg,Ca, and Zn are primarily from the lubricating oil, the ferrous material from wear -6- 8000 0620 PRODUCED BY FORD