Steven Milloy and Michael Gough (Jan. 7) point to the inadequate epidemiology backing up the proposed EPA standards for airborne particulates. The situation is even worse for ambient ozone (smog), where EPA's efforts to tighten the standard are specious and contrary to any cost-benefit criterion. In addition, EPA has chosen to ignore the substantial disbenefits of higher skin cancer rates; ozone, even at ground level, screens out ultraviolet radiation.

Legally, there is no compelling reason for EPA to revise the current ozone standard. The court order obtained by the activist American Lung Association applies only to particulates.

Scientifically, there is no "bright line" for choosing a particular standard. No matter how low the permissible ozone levels are set, there are always some who will be affected or discomforted. Specially vulnerable individuals should not perform strenuous activities outdoors during the occasional days when meteorological conditions cause ozone alerts--any more than prudent individuals should go jogging during a blizzard.

It is a matter of concern that quoted benefit-cost ratios for the proposed standards disagree wildly. While EPA administrator Carol Browner cites benefits of 120 billion and costs of only 6 billion-- a ratio of 20-- Robert Crandall and colleagues, writing in Regulation magazine, complain with ample justification that it is the marginal benefits that need to be compared to marginal costs, and that such ratios would be less than one. There is a clear need here for an independent review of the EPA analysis.

A striking case in point can be made from data supplied by EPA itself. Tighter ozone standards at ground level would remove about 5% of the amounts of ozone that are feared to be removed (in the stratosphere) by CFCs. I have used EPA's rather improbable benefit figure of $32 trillion (!) for phasing out CFC production, cited by EPA assistant administrator Mary Nichols in Congressional testimony on August 1 and September 20, 1995. Assuming that 40% of the US population, in urban areas, is affected by smog, the disbenefits of the tighter ozone standard would reach the astounding level of $640 billion, far exceeding any benefits cited by EPA.