Take the time to enjoy a deep breath next weekend when the 405 freeway in the Los Angeles, California area closes for Carmageddon II. If it’s anything like last year, the air quality is about to get amazing.
In study findings announced Sept. 28, UCLA researchers report that they measured air pollutants during last year’s Carmageddon (July 15-17) and found that when 10 miles of the 405 closed, air quality near the shuttered portion improved within minutes, reaching levels 83 percent better than on comparable weekends.
Because traffic dipped all over Southern California that weekend, air quality also improved 75 percent in parts of West Los Angeles and Santa Monica and an average of 25 percent regionally — from Ventura to Yucaipa, and Long Beach to Santa Clarita.
The study was led by two professors at UCLA’s Institute of the Environment and Sustainability: Yifang Zhu, who is also an associate professor of environmental health sciences at the UCLA Fielding School of Public Health, and Suzanne Paulson, who is also a professor of atmospheric and oceanic sciences.
While the researchers expected cleaner air, they didn’t expect the improvement to be so dramatic.
“The air was amazingly clean that weekend,” Paulson said. “Our measurements in Santa Monica were almost below what our instruments could detect, and the regional effect was significant. It was a really eye-opening glimpse of what the future could be like if we can move away from combustion engines.”
The research gives a peek at what the air would look like in a healthier Los Angeles with a vast majority of hybrid and electric vehicles and shows how quickly less driving can improve key measures of air quality. But to get a regional effect, the researchers said, you need a regional drop in traffic, like what Los Angeles saw during the first Carmageddon — and it doesn’t last if traffic returns.
“The effect was gone by the next week,” Paulson said. “We measured fresh emissions: pollutants that come directly from cars. It’s a very short-term effect.”
Read more from ScienceDaily: http://www.sciencedaily.com/releases/2012/09/120928103754.htm