1st-Stage Smog Alert Tarnishes a Summery Day

Temperatures rose into the 80s across Orange County on Saturday and many residents turned the November day into a reprise of summer, but the sunshine was marred by murky air that prompted authorities to declare a first-stage smog alert.

As some residents cooled their toes by returning to the beach, the mercury topped out at 81 degrees in Santa Ana, but weather officials said today and Monday may be a bit cooler.

Bill Hibbert, a meteorologist with Weather Data Inc., said a bulge of high pressure over the desert that has sent mild Santa Ana winds whirling into Orange County in recent days was beginning to break up, ushering in sea breezes that should cool the region.

Night and morning low clouds will combine with hazy sunshine in the afternoon today, with temperatures along the coast expected to be between 65 and 75 degrees and into the low 80s inland, Hibbert said.

The South Coast Air Quality Management District declared a first-stage smog alert Saturday morning for central Orange County after the area’s Pollutant Standards Index level reached 207. The district issues first-stage smog alerts when PSI levels are from 200 to 275.

Saturday’s air quality improved slightly in the afternoon when the alert was downgraded to “unhealthy” conditions after the PSI went down to 160. The Santa Ana winds probably contributed to Saturday’s air problems, said Thomas Eichhorn, a district spokesman.

The index measures the amount of carbon monoxide, ozone or nitrogen dioxide in the air, Eichhorn said, noting that authorities recommend people stay indoors and refrain from heavy exercise during periods of unhealthful air quality.