On some crisp, spring mornings you can almost taste the ocean, even as far inland as downtown. L.A.'s air is magnitudes cleaner than it was in the 1950s, '60s, and '70s, when you could cut a slice and serve it with a dollop of whipped cream.
So a revelation this week by UCLA researchers could come as a shock:
A joint study by UCLA and the California Air Resources Board found that about 1 in 4 of us city dwellers in L.A. gets a good toke of “noxious plumes of freeway fumes” at our own homes each and every morning, the school announced.
Yeah, according to UCLA, freeway pollution spreads nearly a mile downwind of any freeway and can linger past the morning commute until nearly 10 a.m.
The distance is further than previously believed and means that about a quarter of us are exposed, the school says.
The researchers looked at bad freeway air around the 91, 210, 110 and 101 to come to their new conclusion, UCLA says. Such “tailpipe pollutants” as nitrogen oxide and carbon monoxide were measured.
UCLA explains how communities near freeways (and note here the recent research connecting freeway-adjacent living to children with autism) end up with bad air:
The morning concentration of pollutants near highways is due to a combination of the nighttime cooling of the atmosphere, called a nocturnal surface inversion, and the weak evening breeze. At night, cool air sinks, trapping polluted air close to the ground, where it can't interact with cleaner air from above. As drivers create more emissions overnight and during morning rush hour, Los Angeles' mild “land breeze” pushes the increasing pollution in a plume to one side of the freeway. The cold layer traps the plume until well into the morning rush hour, when sun-warmed air begins to rise and a stronger sea breeze takes over, mixing pollutants throughout the atmosphere and diluting their influence.
Previous data argued that the pollution only spread about one-fifth of a mile downwind from your favorite freeway. The new findings were published in a recent issue of the journal Atmospheric Environment.
And, uh, you early morning joggers? Stop.
Arthur Winer of UCLA's Fielding School of Public Health:
If your home is within about 1.5 kilometers of a freeway, you may want to close your windows during the early morning hours. It's also best not to run or otherwise heavily exercise within the 1.5 kilometer impact zone in the early morning.
Just don't hold your breath.