A smoke advisory has many school districts across Southern California canceling recess, P.E. and high school sporting events.
A staff member at the El Monte School District said some 15 miles downwind from the fire, she could still smell the blaze.
The smoke advisory went into effect yesterday after the Colby fire erupted in the foothills above Glendora. Even though firefighters have extinguished much of flames, school principals are not taking risks.
"They go out and look at the campus and look for things like ash in the air," said John Sterritt, director of L.A. Unified's Office of Environmental Health and Safety. "They look for non-routine odors and the clarity of the air."
As winds carry the smoke into the L.A. basin, the risk is especially high for students with asthma, which affects one in 10 children in Los Angeles, according to county data.
The South Coast Air Quality Management District recommends keeping children with asthma inside and limiting vigorous activity even indoors.
L.A. Unified, California's largest school district, is directing safety efforts towards schools on the East Side. Sterritt said about 60 principals from the area called his office Friday for advice.
Students have a three-day weekend ahead, and officials hope the air will be clear by next week.