LAS VEGAS - Clark County appears headed onto another Environmental Protection Agency air pollution list.
This time it's for ground-level ozone, a component of smog that was measured at unhealthful levels in July in northwest Las Vegas.
A memo Wednesday from acting health district Air Quality Division Director Mike Sword says whether the Las Vegas Valley is considered a serious area for its third pollutant hinges on a U.S. Supreme Court case that tests a tighter standard adopted by the EPA.
That standard - which averages ozone pollution over a more strict, eight-hour period, instead of the existing guideline for one hour - is stalled by a court decision made last year that favored the American Trucking Association. The group argued the eight-hour standard is not enforceable because the EPA does not have an adequate database for setting it.
The valley already is a considered a seriously polluted area for dust and carbon monoxide, a status that requires the state to submit to the EPA plans for dealing with the problems or risk a freeze on federal highway funds.