FRESNO, Calif. (AP) - California's raging wildfires have created a smoky haze so stifling that some doctors in the state's mountain-ringed farm country say their waiting rooms have been crowding with patients struggling to breathe.
Even without the blazes, which have scorched more than 660 square miles statewide, the farming towns and subdivisions dotting the long, flat San Joaquin Valley are typically shrouded in a layer of smog during the summer.
But airborne ash from the hundreds of lightning-sparked fires caused such a spike in air pollution over the weekend that meteorologist Shawn Ferreria said it took his breath away.
"I went and bought a mask because my lungs were not happy with me," said Ferreria, a senior air quality specialist for the San Joaquin Valley Air Pollution Control District. "What we are experiencing is out of historical norms. I thought if I'm going to continue riding my bike to work, I better take an extra measure."
Hundreds of firefighters were working overtime Tuesday to beat back blazes burning from the western edge of the Sierra Nevada to coastal mountains near Big Sur, where authorities enforced new, mandatory evacuations along a roughly 15-mile stretch of Highway 1.
Gov. Arnold Schwarzenegger ordered 200 National Guard troops to report for fire training on Tuesday to later relieve weary crews.
Officials had hoped a fog bank along the Northern California coast would aid firefighting efforts, but the moisture did not extend inland, said Brian Tentinger, a meteorologist with the National Weather Service in Monterey.
Even as crews made headway on some of the worst blazes, air district officials grew concerned that wind patterns could send more smoke billowing into the valley, which is bordered on three sides by mountains.
Once the tiny particles of soot - which are blamed for triggering asthma and other respiratory problems - reach the valley, they're sealed in under a layer of warm air created by hot summer temperatures.
"Our waiting rooms are full of people with sore throats, itchy eyes and sniffles," said Kevin Hamilton, a respiratory therapist with Sequoia Community Health Center in Fresno. "It's certainly driving the clinic's appointments up."
Community Regional Medical Center, the area's only trauma center, showed no increase in respiratory cases. Some health professionals said that could be because asthma patients stayed inside to avoid exposure.
In the San Francisco Bay area, local officials said pollution levels had finally returned to healthy levels after several days of health warnings.
In the Big Sur region of the Los Padres National Forest, about 200 people were ordered to evacuate Tuesday, and evacuation orders remained in place for occupants of at least 75 homes who were forced to leave the region last week.
Endangered condors also sought to avoid the thick smoke by hunkering in cliffs along the Pacific Ocean. Scientists were mourning the loss of a two-month-old chick that they say died when the fast-moving fire swept through the gorge where it was nesting in a 1,000-year-old redwood.
At Tassajara Zen Mountain Training Center monastery in nearby Carmel Valley, students and volunteers stretched sprinklers atop buildings in case embers started falling.
"Air quality is the wrong word. There is no quality," said Chris Slymon, who monitors the monastery's closest phone from a crossroads at Jamesburg 10 miles away.
In the Sequoia National Forest east of Bakersfield, crews from as far away as Kansas struggled to contain a 8,200-acre blaze there. Powerful gusts and choking smoke traveling up the steep canyons hampered their progress, and residents of neighboring towns were ordered to evacuate.
The Kiwanis Club of Mariposa, about 70 miles northwest of Fresno, canceled the town's annual fireworks show at the county fairgrounds because firefighters were using it as a staging area to contain a blaze that has burned through more than 2,700 acres.
Air district officials in San Joaquin Valley said air quality has improved significantly since Friday, when ozone in towns scattered throughout the region reached "very unhealthy" levels.
Schools canceled outdoor activities and residents were warned to stay inside with the air conditioner running. For households lacking air conditioners, the district recommended families hole up in local malls.
If conditions worsen, air managers say they may recommend that other local cities cancel their fireworks displays as well.
"Since there's fires to the north, west and east of us we're kind of surrounded," said Gary Arcemont, a meteorologist with the Fresno-based air district. "Depending on what happens with the intensity and the winds in the next few days, we could be breathing the smoke from any of them."
Associated Press writers Tracie Cone in Fresno and Scott Lindlaw
in San Francisco contributed to this report.
(Copyright 2008 by The Associated Press. All Rights Reserved.)