Effect of Motor Vehicle Pollution Control Programs

From the presently existing or proposed motor vehicle control programs of the State and Federal governments. it is difficult to foresee ever attaining acceptable air quality in the Los Angeles Basin.

Without control of evaporation losses, it is not possible to reduce hydrocarbon emissions to the pre-1940 (no smog) level, and even with evaporation control. hydrocarbon emissions will only approach this goal briefly about 1984 and then begin to rise.

Carbon monoxide emissions will never be less than double those of the prewar years, even under the best of projected standards, and by 1982 will again be on the increase.

Oxides of nitrogen not only are not to be reduced according to present plans. but actually are expected to intensify in inverse proportion to the success of the program to reduce hydrocarbons. This is so because the approach now being taken to reduce hydrocarbons involves "leaning" the air/fuel ratio so that less gasoline and more air enter the combustion chamber. Because the oxides of nitrogen are produced by the chemical combining of the oxygen and nitrogen of the air during high temperature combustion, the increase in the amount of air in the fuel charge leads to an increase in oxides of nitrogen.

The following charts and tables compare the results of the control programs now under way or proposed. These projections assume that cach program operates with full effectiveness and that all devices perform perfectly through out their operating lifetime. It is more realistic to assume that in application the programs will fall somewhat short of this ideal. and that the results will be less favorable than shown here.

To attain acceptable air quality the target levels are going to have to be far lower than any now contemplated, and to attain those levels, allowing for a reasonable percentage of mechanical failures. the aiming point will have to be still lower. If the desired level of control (where smog is no problem) is to be attained within an acceptable time period, rather than the 15 or more years now indicated for the maximum effect of even these programs. some means of accelerating these time schedules must be devised. Better controls are needed sooner.

Effect of Motor Vehicle Pollution Control Programs

From the presently existing or proposed motor vehicle control programs of the State and Federal governments. it is difficult to foresee ever attaining acceptable air quality in the Los Angeles Basin.

Without control of evaporation losses, it is not possible to reduce hydrocarbon emissions to the pre-1940 (no smog) level. and even with evaporation control, hydrocarbon emissions will only approach this goal briefly about 1984 and then begin to rise.

Carbon monoxide emissions will never be less than double those of the prewar years, even under the best of projected standards, and by 1982 will again

be on the increase.

Oxides of nitrogen not only are not to be reduced according to present plans. but actually are expected to intensify in inverse proportion to the success of the program to reduce hydrocarbons. This is so because the approach now being taken to reduce hydrocarbons involves "leaning" the air/fuel ratio so that less gasoline and more air enter the combustion chamber. Because the oxides of nitrogen are produced by the chemical combining of the oxygen and nitrogen of the air during high temperature combustion, the increase in the amount of air in the fuel charge leads to an increase in oxides of nitrogen.

The following charts and tables compare the results of the control programs now under way or proposed. These projections assume that cach program operates with full effectiveness and that all devices perform perfectly through out their operating lifetime. It is more realistic to assume that in application the programs will fall somewhat short of this ideal, and that the results will be less favorable than shown here.

To attain acceptable air quality the target levels are going to have to be far lower than any now contemplated, and to attain those levels, allowing for a reasonable percentage of mechanical failures. the aiming point will have to be still lower. If the desired level of control (where smog is no problem) is to be attained within an acceptable time period, rather than the 15 or more years now indicated for the maximum effect of even these programs, some means of accelerating these time schedules must be devised. Better controls are needed sooner.

EMISSIONS OF HYDROCARBONS AND OTHER ORGANIC GASES FROM GASOLINE-POWERED MOTOR VEHICLES

LOS ANGELES COUNTY

FOOTNOTES FOR TABLE ON HYDROCARBON AND OTHER ORGANIC GAS EMISSIONS FROM GASOLINE POWERED MOTOR VEHICLES

NOTE: These data represent the quantities of air contaminants emitted in Los Angeles County
under various possible applications of the State's program for control of vehicular emis-
sions including:

Installation of crankcase control devices on new cars beginning in 1961, and certain used cars beginning in 1964.

Installation of exhaust control devices on new cars beginning in
1966 which limit average hydrocarbon concentrations in exhaust
to 275 ppm.

Installation of exhaust control devices on new cars beginning in
1970 which limit average hydrocarbon concentrations in exhaust
to 180 ppm.

Installation of control devices on new cars beginning in 1970
which reduce hydrocarbon emissions due to evaporation of fuel
from the tank and carburetor by 88% from their uncontrolled
levels.

It is also assumed that a control device, once installed, will continue to operate at its required efficiency throughout the useful life of the vehicle. For exhaust devices, however, this currently appears unlikely.