Approximately 10 percent of ozone pollution in California’s San Joaquin Valley is estimated to be coming from outside of the state’s borders, particularly from Asia, according to preliminary research presented today, March 31, by the University of California, Davis.
Secondhand smog from Asia and other international sources is finding its way into one of the nation’s most polluted air basins, the San Joaquin Valley. UC Davis atmospheric scientist Ian Faloona shared his research with air quality regulators and scientists today at a transboundary pollution conference near Yosemite National Park. The issue serves as an example of how air quality is a global — not just local — problem.
“To me, it’s an exciting new chapter of how we think of air pollution,” Faloona said. “How do we deal with this not just as an air district of a couple of counties, but as a nation and a global citizen of the planet? Traditionally, air pollution has always been considered an issue to be handled locally, ‘It’s your backyard, it’s your problem.’ But we’re going to have to treat air pollution to some extent how we treat greenhouse gases.”
When someone smokes a cigarette next to you, you know that secondhand smoke is harmful to your lungs, even though you aren’t the smoker. But what about when your neighbor is thousands of miles away, and the pollution they are emitting is from an industrial plant, millions of cars, or a raging wildfire?
Scientists have long known that a portion of ozone pollution was coming from overseas, but attempts to quantify just how much were hamstrung by coarse computer models that overlooked or broadly simplified California’s complex terrain.
Faloona describes California as if it were a human body: The Golden Gate bridge is the mouth, breathing in air from across the Pacific Ocean, sucking it through the throat of the Bay Area and into the lungs of the San Joaquin Valley. Previously unknown is how much air comes over the coastal mountain range and mixes from above into the bathtub of the San Joaquin Valley.
UC Davis researchers have spent the past three years trying to measure that contribution from a mountaintop air quality monitoring station near California’s Point Sur. They’ve also gathered it from a plane equipped with scientific instruments that measure air pollutant levels — a flying air monitoring station of sorts. The combined data has allowed them to analyze the “signature” of the sources and quantify how much of the valley’s ozone pollution is locally produced, and how much is drifting across from international sources.
There is a clean way. What seems more expensive up front isn’t when you look at the big picture.