Las Vegas Valley faces ozone warning, sizzling temperatures

Friday, July 11, 2003 | 9:14 a.m.

Clark County Air Quality officials issued an ozone advisory Thursday effective through the weekend as Southern Nevada's heat wave pushed the air pollutant to unhealthful levels.

Also Thursday the Las Vegas record high for the date of 114 degrees was tied and Nevada Power Co. hit a new delivery peak for electricity.

National Weather Service forecasters are predicting highs near 114 today and said daytime temperatures will continue to sizzle through the weekend.

Today's record high of 116 degrees was set on July 11, 1959, weather service meteorologist Steve Downs said.

The weather service issued a special weather statement Thursday that light winds, combined with temperatures of 110 degrees or higher, would continue into next week.

Thursday's mark of 114 degrees tied the record set on July 10, 1943.

The all-time high ever recorded for Las Vegas is 117 degrees on July 24, 1942.

The torrid temperatures led to increased demand for air conditioning and helped set a record for demand, Nevada Power Co. spokeswoman Andrea Smith said.

Nevada Power set a record peak of 4,772 megawatts at 5 p.m. Thursday, Smith said. The previous peak occurred last July 12 at 4,617 megawatts.

Nevada Power officials expect that Thursday's record will be broken this summer.

Nevada Power has more than 675,000 customers this year, compared with about 630,000 customers a year ago, Smith said. The 1993 peak, in comparison, was 2,681 megawatts with fewer than 400,000 customers, she said.

Increased power generation and vehicle exhausts increased the ozone levels in the air Thursday.

An air monitoring station at Rainbow Boulevard and Alta Drive registered an unhealthful level of 114 parts per million of ozone on Thursday. Any level above 100 parts per million is considered unhealthful.

Ozone is a key ingredient of urban smog. During the hottest months, ozone from vehicle exhausts, power plant emissions, paint and hair spray combine with sunlight, forming the pollutant at ground level, Stacey Welling, a county spokeswoman, said.

Under the air quality advisory, active children and adults as well as people with respiratory diseases such as asthma should limit outdoor activities.

Symptoms of exposure to ozone include coughing, wheezing and shortness of breath.

The heat has even affected where boaters can launch on Lake Mead, National Park spokeswoman Roxanne Dey said.

Hemenway Harbor was closed to owners launching boats that are longer than 20 feet, Dey said. Lake Mead's water level has reached 1,143 feet, after dropping due to dry conditions.

"It's one of the most popular and most used boat launch sites on the lake," Dey said, adding that the only deep-water launch areas opened are the Boulder launch ramp next to Lake Mead Marina, Echo Bay and Callville Bay.