Wildfire smoke a factor in poor air quality through Wednesday

By Mary Manning

Monday, Aug. 31, 2009 | 10:06 a.m.

Clark County officials have extended an air quality advisory through Wednesday because of smoke from a massive Southern California wildfire and ozone in the Las Vegas Valley forming because of hot temperatures.

The county's Department of Air Quality and Environmental Management issued an advisory today for ground-level ozone because of the wildfires sending smoke into Southern Nevada on southwesterly winds.

Local weather conditions, with winds expected at less than 25 mph, and existing levels of pollution from the weekend prompted the extension, county officials said.

Smoke combines with small dust particles and other pollutants that can aggravate respiratory diseases.

At this time excessive air pollution isn't occurring in Las Vegas, but as the valley's air heats up over the afternoon hours, ozone forms at ground level and combines with the smoke.

Ozone occurs naturally in the upper atmosphere and protects the Earth from the sun's harmful ultraviolet rays. At the ground level, ozone is a key ingredient of urban smog during the hottest months of the year.

Unhealthy doses of ground-level ozone can reduce lung function even in health people, and worsen respiratory illnesses. Ozone exposure can result in coughing, wheezing and shortness of breath.

To check ozone and pollution levels, go to the county's Web site at www.accessclarkcounty.com/depts/daqem/Pages/index.aspx.