THE BENEFITS of pollution control are very substantial, but it's worth keeping an eye on the costs as well. Among the defenders of the present environmental protection laws it is frequently regarded as irrelevant, not to say immoral, to add up the economic costs of a good cause. But the patterns that emerge provide a reliable guide to choices that have to be made. And the amounts at issue are not small. In 1981, the last year for which precise figures have been calculated, Americans spent $60 billion for pollution abatement and control.

The figures come from that undramatic but enormously valuable audit of the American economy, the Commerce Department's national income and product accounts. Two of the department's economists, Gary L. Rutledge and Susan Lease-Trevathan, have now published a survey of public and private antipollution expenditures for the past decade. The total outlay rose steadily to 1979, then began to decline slowly.

The chief reason for the decline has been the reduction in public spending on sewer systems. In broad terms, spending on water pollution has been falling while spending on air pollution has continued to rise. The largest rise recently has been in, specifically, the costs of reducing the air pollution generated by automobiles.

That sharpens a question already before the Environmental Protection Agency and Congress. The medical evidence accumulated over the past decade indicates that the three legally controlled pollutants from automobile tailpipes have only slight effects on people's health. Meanwhile, the same kinds of evidence point to much more important health effects from certain kinds of water pollution and, above all, from the air pollution generated by power plants. All attempts to rewrite the present legislation are deadlocked between the people who don't want to relax the automobile standards and those who don't want to tighten the industrial standards. The result is an increasing share of the spending on the least dangerous forms of pollution and a declining share on the most dangerous.

The total cost to business of pollution control and abatement, including capital cost as well as direct spending, was $54 billion in 1981. That figure can be viewed as a pollution tax. As such, it's a good deal larger than the total revenues from the corporate income tax. While the income tax is spread across all corporations that make profits, the pollution tax is concentrated on a few--notably the metals, chemicals and electric power industries. A tax on industrial pollution is fair and desirable. But the level is now high enough to affect profoundly the way the national economy works. A congressional review of basic environmental policy is badly overdue.