Don't breath, at least very deeply. We are in another huge fire season, as we have been every since the year 2000. It seems that no matter how much rain or snow, we still get fires here at the first nice day.
There was a brochure put out a year ago called "Bitterroot Valley air quality." It gives a visibility index:
Three to 5 miles: unhealthy for sensitive groups; 1.5 to 2.5 miles: unhealthy; 0.9 to 1.4 miles: very unhealthy; 3/4 of a mile or less: hazardous.
Particular matter of 2.5 micrometers are a fraction of the size of a human hair; they travel deep into the lungs and the body can't expel them, causing increased respiratory symptoms, irritation of airways, coughing, difficulty breathing, asthma, bronchitis, irregular heartbeats, nonfatal heart attacks and premature death in people with heart or lung disease.
We should know this when exposed to these fires every year. Whether man-made or not, these fires, if not contained, affect us and every living creature.
Do everything we can to prevent fires, and put them out. Remember, many of these fires are man-caused.