While residents of Fresno and Clovis mistook the smell of acrid smoke for a neighborhood fire, the assumption proved to be a false alarm. A thick haze settled over the San Joaquin Valley on Sept. 7.

Division Chief Walt Chacon, of California Department of Forestry and Fire Protection (Cal Fire), monitored the source of the smoke. Chacon directs a vegetation management program to prevent future fires.

“The smoke from the Moonlight fire in Plumas County was pushed by the wind through a natural pass in the mountains and into the Central Valley,” Chacon said. “Since the valley is surrounded by mountain ranges, the smoke got trapped from the city of Redding to Bakersfield.”

Smoke from the wildfire, made up of particulate matter called PM2.5, created the haze seen in the valley. Maricela Vel