BERKELEY, Calif. (KGO) -- It's hard to breathe for many of us in the Bay Area as we have another Spare the Air day.
Bay Area Air Quality warns that the air, made thick by smoke, can irritate your throat, trigger athsma, or worsen many illnesses.
"Avoid any outdoor activities, especially if you suffer from a respiratory condition or are a child or elderly person," said Sarah Zahed.
You should also avoid the smoke if you have a heart condition.
All the iconic views of the Bay Area were blotted out by the smoky skies for much of the day. Scientists at UC Berkeley are gathering data on the smoke to learn more about everything from the atmosphere to the agriculture.
Conditions have been clearing up in the East Bay. There is at least some visibility now. You can see your shadow. Earlier Friday it was a total smoke out.
RELATED: East Bay bathed in smoke-driven smog
"We are really worried about the air quality and the effect on our health and our kids," said Davis resident Sharad Jain. "We're trying to stay inside."
It was a quiet day up in the Berkeley Hills.
If you tried, really tried, you could manage to see the outline of San Francisco beyond the campanile.
"Today we are seeing that fires in British Columbia, Oregon, and California are all mixing together and making this lovely soup that we're breathing today," said UC Berkeley Professor of Chemistry Ron Cohen.
Cohen is doing research on atmospheric chemistry. He says for scientists, the smoke in the air provides a chance to learn more.
"We have a big network that Berkeley manages that makes measurements from San Francisco to San Leandro to Vallejo and we will look at those observations over time," he said.
"We are making measurements in the Sacramento Delta right now and we're looking forward to seeing these measurements and how they affect our data," said UC Berkeley Bio-Meteorology Professor Dennis Baldocchi.
He says smoke reduces the light for the photosynthesis of plants, thus smoke like this could impact California agriculture. But they're also looking at how the smoke could have unintended positive effects.
"Smoke causes light to come in from many many angles compared to a sunny day," Baldocchi said. "When light comes in many angles it can penetrate deeper into the forest."
So, bottom line, the smoke could be altering our ecosystem especially if layers of smoke for days and weeks becomes a normal summer pattern with the increase of fires.
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