See also:

*Why Carmageddon II Could Be For Real; 10 Freeway Stretches in L.A. to Avoid.

Having to be cooped up for this weekend's Carmageddon II is going to suck (L.A. leaders are encouraging you to keep shopping, so long as you stay away from the 405), especially since a fall heatwave is going to spark mega-hot temperatures around here starting Sunday.

But … there is one good thing about the 405 shutdown between the 10 and the 101 starting as early as 7 tonight (and lasting as late as 5 a.m. Monday):

The air around here will be much cleaner. You see, not everyone on the Westside drives a Prius, despite popular perception.

UCLA reports that a study of last year's Carmageddon shows an 83 percent improvement in air quality around the closed portion of the 405 during that July weekend. Wow.

The improvement wasn't just felt in West L.A. and the Sepulveda Pass but all around Los Angeles as motorists stayed off the roads. UCLA:

Credit: UCLA

Credit: UCLA

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 pollution was back within a week, though, researchers said.

Study co-author Suzanne Paulson, who is also a professor of atmospheric and oceanic sciences, remained impressed:

The air was amazingly clean that weekend. 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.

Boom. Maybe we should have Carmageddons more often. UCLA, for one, is calling it Carmaheaven.

Read more here.

[@dennisjromero / / @LAWeeklyNews]

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