"I have shortness of breath," said smoke-inhalation victim Margaret Cedeno. "My chest."
The dirty air has sickened many who have taken shelter down the mountain from the Running Spring fire, CBS News correspondent Sandra Hughes reports.
"They come here with breathing problems, tightness in the chest," said Dr. Margaret Beed of the San Bernadino County Department of Public Health. "One man had a heart attack last night."
When April Acosta was evacuated, she forgot to grab her asthma medicine. It's been three long days.
"You can't breathe," she said. "I started having panic attacks."
What's in smoke? Depending on what's burning, it could include:
Some of the chemical irritants and particulates can be so tiny that they're inhaled deep into the lungs.
"It's like smoking a pack of cigarettes a day," said Dr. Dee L'Archeveque of the Community Hospital of San Bernadino.
In the smokiest of areas, schools remain closed. And what is good news for firefighters on the frontlines …
"The winds are dying down," a weather report said.
… isn't going to bring relief to people's lungs. Without those winds, the pollution isn't going anywhere.
You are breathing stuff that gets past your defense mechanisms. It goes by your lungs and by your throat and goes down to your lungs and just sits there.
So for now doctors say stay inside - hold off on that outdoor run and wear a mask.