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Bay Area Headlines: Thursday, 4/16/20, AM


Measuring California's Air Pollution During Shelter-In-Place / Public Transit Agencies Honor Essential Workers

Measuring California's Air Pollution During Shelter-In-Place

California is in the middle of an unexpected experiment. There are way fewer cars on the roads because of the stay-at-home order and that has resulted in cleaner air. Scientists say this moment presents an opportunity in the fight against climate change.

Harvey Mudd College chemist Leila Hawkins has a home lab where she uses a series of octopus-like tubes that allow her to gauge air quality through a hole in the roof. She uses a mass spectrometer to measure the amount — and type — of pollution. She can see the measurements every 10 minutes on her home computer. “Yeah," she says, "The air seems cleaner, but it's definitely not zero.” 

There are still pollutants in the air like organic materials from cleaning products, perfumes, and shampoos, as well as fumes from cars. Hawkins says, "The silver lining is not that we have good air quality now. It's what scientists can learn from this information."

In LA there are around 35 percent fewer cars on the road and around 65 percent fewer in the Bay Area, according to the air districts in each region. 

Since Californians have been staying home over the last three weeks many varieties of pollution are down, according to the private air quality company Aclima. For example, compared to the last few years particulate matter has dropped by as much as 35 percent. Those tiny particles can cause major health issues and come from things like cars or factories. 

And levels of a pollutant called black carbon have been cut in half since sheltering in place began. Meg Thurlow with Aclima says it’s been "an unprecedented natural experiment. And it's helping us understand how pollution levels are impacted by large scale behavior change."

"We can see that from the ground and from space," says Ron Cohen, who studies air quality at UC Berkeley. He says the statewide data are similar to measurements from cities like LA or San Francisco. His results show nitrogen oxides are down by a third. That comes from burning fossil fuels. Cohen’s excited about the results, but he isn’t happy it’s coming at the expense of the economy. "We don't want it to go much further because half the nitrogen oxide emissions are trucks and those trucks are our lifeline. They're bringing us all the goods and services we need."

Air districts in rural areas like the Central Valley, and even in Sacramento, aren’t seeing as significant reductions possibly because the populations are smaller. Still, Cohen says the positive results present a teaching moment about how our actions can prevent climate change from worsening.

Public Transit Agencies Honor Essential Workers

BART, AC Transit, Amtrak and other transportation agencies nationwide will sound their horns today at noon to honor essential workers amid the coronavirus pandemic.