Health issues seen as fires darken skies

Thursday, June 30, 2005 | 11:04 a.m.

Smoke from nearby wildfires has again blanketed Las Vegas with a thick cover of haze and, along with rising ozone levels, could cause health problems for some people.

The Clark County Air Quality and Environmental Management Department issued an ozone alert Wednesday afternoon warning sensitive people to avoid strenuous exercise, especially outdoors, through Friday. Mike Sword, Air Quality engineering manager, said while ozone was a primary component of the bad air, the haze was actually a product of a mix of different noxious pollutants.

Particulate matter, which is usually fine dust kicked up from the desert but in this case the airborne detritus from the wildfires in the Southwest, contributed to haze, Sword said.

He said particulate matter, although not exceeding federal air quality limits Wednesday, was about four to five times what is usually is in the Las Vegas Valley.

Sword said Air Quality scientists did not completely agree on the source of the particulate matter and ozone. Some believed it was more of a product of Las Vegas heat and urban activity, while others said the wildfires were the culprit.

Ozone, while itself invisible, is a primary component of smog and becomes a concern in Las Vegas during the hot summer months. Bright sunlight, stagnant air and pollution from cars and other sources combine to create ozone at ground level.

Unhealthy levels can impair lung function and exacerbate respiratory problems such as asthma, and induce coughing, wheezing or shortness of breath in health people, the department reports.

"When we're at this level, it's unhealthy for sensitive groups," Sword said. "It's a level at which most people should exercise some precautions."

The hot desert sun will continue producing the gas through interactions with the wildfire smoke and Las Vegas' own pollution, he said.

"As long as the sun is up, we're going to have elevated levels of ozone."

Brian Fuis, a spokesman with the Las Vegas office of the National Weather Service, said the haze and bad air could last for several days. He said wildfires burning near Mesquite and scattered throughout Arizona are teaming up to throw smoke toward Las Vegas.

He said the haze was "pretty thick and constant over the valley" Wednesday, but was not thick enough to impact aviation. However, it could contribute to impressive sunsets, Fuis said.

The federal Bureau of Land Management, which oversees land on which fires are burning, detailed a number of ongoing fires Wednesday. Among them:

All the fires were started by lightning.

The fire-related air pollution problems contribute to an ongoing problem with ozone in Southern Nevada. The Las Vegas Valley does not now comply with federal standards for the potentially dangerous gas.

The Air Quality department is working to draft a plan to control ozone and win federal approval for the plan, which could be in place by 2007. Approved plans already are in place for control of carbon monoxide and particulate matter.

County officials say simple efforts could significantly affect the amount of ozone in the air. Among their suggestions: