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The War Against the Automobile

Emissions

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When Los Angeles began to notice air-pollution problems, it began to do something about them. An air-quality board was established and began to prohibit various types of polluting activities. The oil refineries were found to be a major source of pollution and were required to clean up their processes. Outside incineration of trash was also prohibited. Then L.A. began to go after the automobiles. And the L.A. and California programs have generally been followed by the rest of the country.
The first step was easy-preventing the escape of hydrocarbons from the oil in the engine's crankcase.. The fitting of positive crankcase ventilation valves (FCV) in the early 1960s accomplished this cheaply and very simply. It was also found that hydrocarbons entered the air by evaporation from gas tanks and carburetors, and evaporative controls were required in the late 1960s. These two steps alone reduced hydrocarbon emissions from automobiles by 45 percent.
Exhaust emissions have been a little tougher to control. Beginning in 1968, federal standards were mandated for automobiles, which were annoying to drivers because they cut into performance, reliability, "driveability," and economy. But by 1970 the redesigned cars were producing only 30 percent of an uncontrolled car's emissions. It wasn't velY difficult to cut emissions once the problem was recognized. Remember that for seventy years automobile engines have been designed to maximize easy starting, perfOlmance, fuel economy, reliability, and smoothness, and to minimize weight and cost. Recognizing emissions as a new parameter merely complicated the design a little bit more.
It took a while for the engineers to learn how to deal with emissions, but they have done so pretty well.
In 1970 the Congress (which I believe does not include any engineers) responded to environmental agitation by passing the Clean Air Act, which required that by 1976, auto emissions be reduced to 10 percent of existing levels. That doesn't sound very difficult, does it? The trouble was that Congress didn't require the reduction of the level of emissions to 10 percent of uncontrolled cars, but to 10 percent of 1970 cars-which were already

producing only 30 percent of the emissions of uncontrolled cars.o Ten percent of 30 percent is 3 percent. That is tough. To squeeze down to the last little bit of anything is incredibly difficult.
Maybe you can get 90 percent of the juice out of your orange, but the remaining 10 percent is tough, and the last 1 percent is impossible. In the real world the cost of achieving totality approaches infinity and increases exponentially. Typically, if it costs a thousand dollars to achieve 90 percent of something, it will cost ten thousand to get 99 percent, a hundred thousand to get 99.9 percent, one million to get 99.99 percent, and so forth. That last bit is always a backbreaker.
But even that would not have been so bad if the Congress had stuck to unburnt hydrocarbons and carbon monoxide, which both result from incomplete combustion processes. So improving combustion by detailed modifications of major design changes reduces both, but the rub is the oxides of nitrogen. Decreasing the hydrocarbons increases the NOx' Look at the chart (Figure 2). An auto engine runs on a mixture of gasoline and air-the normal operating range is from 13.5 to 16.5 parts air to one part gasoline. Within normal operating ranges, hydrocarbons and CO can be reduced by increasing the ratio of air to fuel but NOx goes up. This is simple to understand.
Reducing HC and CO requires better combustion to obtain more combination with oxygen, producing halmless H2O and CO2.
But better combustion also results in more combination of nitrogen with oxygen, producing NOx' The nature of operation of the Otto-type internal-combustion engine, used in almost all cars in the world, precludes eliminating both hydrocarbons and NOx.
Now the reader may reasonably ask this question: If the smog is caused by the combination of NOx and hydrocarbons, why is it necessary to get rid of both of them? That is an excellent ques-

" The father of smog, Professor Haagen-Smit, said "the Muskie bilI passed last December [1970] without Congress understanding that emissions in 1970 vehicles had already been controlled 70 to 80 percent." He described the EPA air quality standards for hydrocarbons as "absurd."

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