UPLAND (CBSLA.com) — Two fires burning in the Angeles National Forest near Azusa and Duarte prompted a smoke advisory to be issued Monday for the Inland Empire.

The South Coast Air Quality Management District said smoke from the blazes was drifting east toward Riverside and San Bernardino counties, and the air quality could reach unhealthy levels.

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And it did. Ashes were seen falling from the sky in Upland Monday night, adding more misery to the already extreme, triple-digit heat in the area.

“It’s almost like snowing. But it’s ash,” one man said.

The smoke also blocked the light from the sunset and cast a purple, gray haze. One could barely see the mountains and foothills through the thick smog.

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Megan Stevenson worked with children at a summer camp in Fontana. “We’ve got to have everyone inside because it’s so bad. Trying to keep the kids safe and out of unhealthy situations,” she said.

Plenty of people in the area were doing the same thing at home. CBS2/KCAL9’s Erica Nochlin saw three different families in just 15 minutes, buying new filters for their air conditioners.

People are urged to avoid unnecessary outdoor activities and change the filters in their air conditioners.

You should also avoid using a swamp cooler or whole-house fan because that could bring more smoke inside.

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Wood-burning appliances, outdoor or indoor, should also be avoided.