Sifting air rules

ONE part of the proposed changes in federal clean air standards deservedly is winning applause. But there are two reasons why other aspects of the changes are cause for concern.

The changes in the public health aspect of clean air standards were proposed over the weekend by William Ruckelshaus, administrator of the Environmental Protection Agency. No decision will be reached for several months, while all sides have the opportunity to comment on the proposals.

Even then, if the past is a guide, there could be several years of court suits before it is certain whether the new standards will be judged legal.

What is being generally applauded is the proposed change from measuring particles of all sizes in the air to concentrating on the very small ones, with a diameter much less than that of a human hair. Environmentalists are pleased with this change, noting that many scientists conclude small particles, not large ones, constitute a possible threat to health. In addition, removing the strict standard on large particles would ease a cleanup burden now seen as unnecessary for some industries, such as mining firms, which produce relatively large particles, but not small ones.

However, there is concern that, after all public comment is complete, the EPA could decide to weaken the public health standards, a move that environmentalists would consider unwise. Rather than offer a specific standard for the smaller particles at this time, Mr. Ruckelshaus at the moment has proposed a sliding scale, from which the precise standard later will be selected. This scale ranges from, at the stricter end, an approximate continuation of the current level of stringency, to a considerable relaxing of that standard.

At the weekend Mr. Ruckelshaus said he was ''leaning'' toward coming down on the stiffer end of that scale; there is no certainty that this will be the final decision.

There is one other area of concern - that there may be no effective federal health standard for the amount of particles for several years, until the new standard becomes fully operational.

Keeping existing standards on all airborne particles should be considered until the new standard not only is decided upon, but also has met all court challenges - and until states have come up with their own regulations for putting it into effect.

As things now stand, once the EPA decides on a new standard the old one will cease to have effect. As a consequence there could be an effective hiatus in health standards of four to five years while the legal testing proceeds.