Washoe County Health District spokesman Phil Ulibarri said Thursday the air quality index has risen into the unhealthy range for sensitive groups.
He says the pollution index was in the good range of 50 earlier in the day, but jumped to 130 by mid-afternoon. Between 100 and 150 is considered unhealthy for those with respiratory ailments, the elderly and young children.
Ulibarri says it's a fluid situation they will monitor into the night. If the index surpasses 150, the general population likely would experience some health effects.
The fire west of Yosemite more than tripled in size overnight to more than 84 square miles.