CONGRESS IS NOW rewriting the Clean Air Act, and it's turned into a bitter debate over the pattern of industrial development in this country. When Sen. Edmund Muskie and his colleagues wrote the present basic law seven years ago, neither they nor anyone else could know its full implications. By now, both the health benefits and the hard choices have become a good deal clearer. Since this revision will be going forward when the Carter administration brings out its energy program next month, this year may be the point at which the federal government finally pulls its policy on fuels and its policy on the environment into some coherent relationship to each other.

Of all the Clean Air issues, the long quarrel over automobile emissions is now closest to a satisfactory resolution. The early stages of the law have forced the automobile companies into technical improvements that will soon make possible even more remarkable gains. New engine designs, the rapid development of increasingly effective catalytic converters, the appearnace of light and clean diesels: all of these advances change the nature of the trade-offs. Several years ago, it seemed that clearner auto emissions would exact a high price in poorer fuel economy. But recent engineering refinements have greatly reduced this penalty; further refinements in the near future may eliminate it altogether. The case for compromising the original targets laid down in 1970 are becoming steadily weaker.

It's much harder to decide what to do about pollution from stationary sources, which mainly means heavy industry and, above all, coal-burning electric generating plants. Much of the country is already in violation of the air quality standards that the Environmental Protection Agency has set. Does that mean no new industrial development there? The EPA has worked out a reasonable set of regulations that now need to be written into the statute. If a steel mill, for example, wants to expand, it has to reduce the pollution from its present plant to ensure that its total emissions will not increase as it grows. The same principle applies when a new plant comes to town. Then it is the state's responsibility to but back other sources of pollution in the vicinity, to keep the town moving steadily toward clearner air.

But the development issue gets much harder in those regions where the air is still pristine. Court decisions, elaborated in other. EPA regulations, have had the effect of nearly prohibiting heavy industry in many of these areas, particularly those near federal parks. That almost rules out large-scale industrial development in those states with a lot of federal parkland. But some of those states are also the sites of massive coal deposits. If the country is going to shift its power system from oil to coal, as a matter of national policy, what happens to air quality rules for the state of Utah?

Seven years' experience, since the basic federal law was passed had demonstrated that progress toward cleaner air is not easy. Many of the original deadlines have had to be extended, sometimes repeatedly. But those deadlines have forced genuine and dramatic improvements in technology. The costs of pollution control, in money, are real and they are important. The fuel efficiency costs, in contrast, tend to be temporary. As for the benefits in health protection, they turn out to be even more significant than the authors of the 1970 law knew.

In making up your mind about Clean Air standards and coal, it's helpful to remember that coal smoke contains sulfur. If that sulfur gets into the atmosphere, it poisons the people who breathe it. The effects on a person's lungs, over a period of years, is frequently fatal. The shift to greater use of coal in this country is no excuse for relaxing the legislation. To the contrary, it will require greater federal vigilance and tighter controls to ensure the quality of the air that we all breathe.