County issues seasonal advisory for ozone, wildfire smoke

People vulnerable to air pollution — those with respiratory problems, cardiac disease, young children and senior citizens — should stay inside during the hottest hours and keep windows and doors closed on days when ozone levels climb, local air quality officials said.

The Clark County Division of Air Quality this week issued its annual seasonal advisory for ozone and wildfire smoke, which will remain in effect until Sept. 30.

The U.S. Environmental Protection Agency defines ozone as a colorless, odorless gas that occurs naturally in the air. It can build to dangerous levels when pollutants, smoke, chemicals and hot temperatures combine, the agency said.

Kevin Macdonald, public information administrator for the Clark County Department of Environment and Sustainability, said June, July and August typically marked the worst period for heightened ozone in the Las Vegas area.

Ozone development doesn’t just happen as a result of smoke and heat, Macdonald said. It depends on the amount of sunlight, pollutants and the weather on any given day.

“If the winds blow it through, that helps to minimize ozone,” he said. “If there are no breezes, those pollutants can cook and stagnate.”

The department’s senior meteorologist, Paul Fransioli, said summer weather, pollutants from vehicles, other sources locally and blowing in from Southern California can combine to produce dangerously high levels of ozone.

“We will likely have days this summer when ozone concentrations in the valley exceed the EPA’S standard,” Fransioli said.

That standard, 70 parts per billion over a rolling eight-hour average, usually only occurs in two or three spots in the valley at a given time, based on readings from air monitors.

“Here in Clark County, the areas that seem to get more ozone concentrations are to the south and west,” Macdonald said.

Last year, the county department recorded 18 days when ground-level ozone exceeded the EPA standards.

Wildfire smoke, meanwhile, is made up of particles that worsen ozone development. Last year, wildfire smoke affected ozone levels on 11 of the 18 days that exceeded EPA standards, MacDonald said.

Exposure to ozone can irritate the respiratory system, which can cause coughing, a sore throat, chest pain and shortness of breath, officials said. The symptoms can be worse for people with respiratory conditions such as asthma, officials said.

The Asthma and Allergy Foundation of America ranked the Las Vegas metropolitan area as No. 24 among 100 “asthma capitals” in the United States, based on the prevalence of asthma, emergency room visits and fatalities due to asthma last year.

rhiannon.saegert@gmgvegas. com / 702-948-7836 / @musettasun