University of California, at Davis researchers spent three years collecting air samples by plane over the San Joaquin Valley and Point Sur on the coast. They were able to determine the signature traits of ozone particles from different areas, aiding in identifying the origins.
Researchers found that10 percent of the ozone pollution, the primary ingredient in smog found in the Central Valley’s farm region came from other countries, mainly in Asia. Ian Faloona, an atmospheric scientist, presented the findings on Tuesday at a conference of air-quality experts and regulators near Yosemite National Park.
“What’s happening upwind strongly affects what’s happening downwind,” Faloona said. Likening California to a human body, and the San Francisco Bay as its mouth, he said the mouth is “breathing in air from across the Pacific Ocean.”
Faloona’s conclusions are still only preliminary, but the study was critical in helping to explain the recent increases in air pollution in California, especially with the continuing drought and warmer temperatures triggering a rise in the number of days with increased soot and dirt in the air this past winter.
On the same day that Faloona was presenting his findings, another study by UK and Malaysian researchers was published in Europe. This study showed air pollution from China could travel 1,000 kilometers (621 miles) a day during “cold surges,” reaching the tropics.
“Traditionally, air pollution has always been considered an issue to be handled locally,” Faloona said, citing the example of California being divided into ‘air districts’. “But we’re going to have to treat air pollution to some extent how we treat greenhouse gasses,” he argued.
California was out of compliance with federal ozone rules last year for 99 days, up from 89 days in 2013. Faloona is urging state officials to look beyond regional sources for air pollution. “Gradually we’re starting to come to this understanding that pollution is actually of a larger scale than we originally planned for and thought about,” Faloona said.