In brief / In brief

Why isn’t Berkeley air quality impacted by red, smoky skies today?

Orange skies and a bloody sun greeted Berkeley residents on the tail-end of Labor Day weekend, but air quality is in the “healthy” range, despite the heat, the apocalyptic visuals and the large wildfires in Northern California.

The Bay Area is directly downwind from the over 300,000-acre August Complex fires burning in Mendocino and neighboring counties, according to the National Weather Service, but extremely strong winds are pushing smoke about 5,000 feet up in the air through a process called “turbulent mixing.”

Smoke has to be at about ground level to affect the air quality, which started off healthy today, according to a Bay Area Air Quality Management District monitor at the Aquatic Park, but had dipped to the “moderate” level by the noon count.

“It’s kind of like if there’s a pile of dust, and someone took a leaf blower to it and flung it all up into the air,” said Drew Peterson, NWS meteorologist. “If winds were weaker, then gravity would take over and allow these [smoke particles] to all fall to the ground.”

Residents in the Berkeley and Oakland hills may experience some ash later today if the smoke continues to drop. It’s being alleviated by a marine layer and was hovering about 2,500 feet up in the air as of noon, according to the NWS.

The thick smoke is also reflecting sunlight and preventing temperatures from reaching their full potential, providing bittersweet relief from the triple-digit heatwave that lasted from Saturday to Monday.

As for the spooky orange tint, that’s because longer wavelength light (reds and oranges) is able to push through smoke particulates, whereas shorter wavelengths (blues and purples) are filtered out, Peterson said. Check out some photos of the resulting “red shift” that’s giving Berkeley its sepia filter Tuesday, Sept. 8.