Emissions from In-Use Catalyst Vehicles

Sulfate Emissions from Vehicles on the Road

“…On this basis, the catalyst-car SO4~2 emission rates would become 5 to 20 mg/km at Allegheny, 3 to 8 mg/km at Tuscarora. Therefore, and especially since most of the errors in our experiment are apt to lead to underestimates (Appendix IV), we question the recent assertion 35 (evidently derived from the Albany study 34 ) that the average sulfate emission rate from catalyst-equipped 49-state cars is only 1.7 mg/km (2.7 mg/mi).…”

“…One study, of California cars, 33 gives emission rates lower than the EPA Baseline Experiment by nearly a factor of 2 when account is taken of differences in vehicle type and fuel sulfur level. The other study, 34 of cars around Albany, NY, gives fuel sulfur adjusted results lower than the EPA Baseline Experiment by a factor of 3 for air pump systems and 6 for non-air pump systems. Our results, and other evidence such as deficient and erratic sulfur balances between sulfur consumption and emission in the Albany and California studies, lead us to doubt the low results of those two studies.…”

Effects of manganese deposits from MMT on automotive catalysts in the absence and presence of other fuel additives

“…These catalysts, designed to remove NO, CO, and hydrocarbons simultaneously, are intrinsically much more prone to poisoning (1). In these laboratory experiments we were not concerned with catalyst deactivation by physical causes (plugging of catalyst pores and channels), which is an intrinsic problem associated with the deposits derived from MMT, even at lower concentrations (2,8).…”

Epa’s Catalyst Research Program: Environmental Impact of Sulfuric Acid Emissions

“…EPA's emissions testing research has also resulted in a method for measuring soluble sulfate in auto exhaust based on the formation of chloranilic acid from barium chloranilate. 9 Using the S-7 cycle, tests have been carried out at 5000 mi intervals. As in the Olson Laboratories study, sulfate emissions were low, averaging 2.7 mg/mi for 27 tests, considerably lower than California vehicles.…”