California Air Quality: Should You Wear a Face Mask for Wildfire Smoke? – The New York Times
How bad is the air?
Air quality is graded on a color-coded scale, with green for good quality, and yellow, orange, red, and purple representing increasingly significant risks.
After the Getty fire broke out on Monday, the Los Angeles area was experiencing moderately hazardous conditions — in the yellow category — with some locations recording air that was unhealthy for sensitive groups, coded orange.
The Bay Area was also experiencing conditions in the orange range, with some “spikes” into the red range, which is generally considered unhealthy for everyone, according to Kristine Roselius, a spokeswoman for the Bay Area Air Quality Management District.
“It’s not great,” said Ms. Roselius, who recommended that people in the region stay indoors. Still, she said, the air quality in the Bay Area was not as bad as it was during the Camp fire, which blazed for more than two weeks in 2018, claimed dozens of lives and became the deadliest wildfire on record in California. “That was far more widespread, and it was higher levels,” she said of the air quality problems from that fire.
In general, wildfires come with a risk of breathing particulate matter, tiny pollutants too small to see individually that can cause a range of harmful effects when inhaled into the lungs.