No one can be sure. But physicians say it's common for patients to take "breathing vacations."

A BREATH OF FRESH AIR: Jay Orvis, a bronchitis patient, left the Valley and moved to Carson City, Nev., because doctors advised him to move. (Mark Crosse / The Fresno Bee)

Joseph "Jay" Orvis, 54, left Fresno in July 2000, after doctors advised the U.S. Forest Service worker to move.

Orvis recalls his 18 years in Fresno: "I constantly had bronchitis and I was on antibiotics all the time. That only works for so long, and then it fails to work."

He feels better since moving to Carson City, Nev. "I notice over here that my lungs don't hurt," he says. Orvis is in charge of timber sales administration for the Lake Tahoe Basin.

Breathing dirty air in the Valley for so many years weakened his lungs, Orvis says. And his lung problems haven't completely disappeared now that he is living in Nevada. Last month, doctors prescribed intravenous antibiotics for a lung infection that made him weak and tired.

But, he adds, "If I'd stayed in Fresno, I'm afraid it would be worse, probably quite a bit worse."

He didn't want to leave Fresno, and says he misses it: "The Valley became my home. I had a lot of friends."

But visiting the Valley reminds him of why he left.

"When I come back to Fresno and I come over the Sierras and I look at the air over the Valley, I'm almost appalled at what I see," he says.

Air pollution drove Dr. Stephen Ciesielski and his wife, Lorraine Harris, out of Fresno in 1994. They now live in Beaufort, S.C., a community between Charleston and Hilton Head.

They had mixed feelings about leaving Fresno.

Ciesielski, 44, sounds nostalgic over the telephone in his South Carolina clinic office, as he recalls scuttled plans to practice family medicine in Fresno. The Valley needs doctors who speak foreign languages and he wanted to put his Spanish to use, as well as the Hmong language he was learning.

Ciesielski enjoyed their home in the eclectic Tower District of Fresno, where they lived for about a year in 1993. "That's our favorite house we ever lived in," he says. "I would love to go back, just to see that neighborhood."

Harris, 48, was supportive of her husband practicing medicine in Fresno.

"We just thought it was a wonderful area, but regrettably so spoiled by its pollution situation."

She had no choice but to leave Fresno, she says. She couldn't breathe. "I developed asthma."