If there’s a silver lining to the COVID-19 pandemic it may be that the health crisis, which has resulted in the most drastic economic shutdown in Los Angeles history, has also produced the longest stretch of clean air the city has seen in more than a generation.
The March 2020 air quality index compiled by the Environmental Protection Agency confirms what millions of Angelenos can see just by looking out the window: the brownish haze that customarily settles atop the city on weekday afternoons has lifted and visibility has cleared for miles in every direction since the “safer at home” order was imposed.
Last month, Los Angeles experienced the longest stretch of days of “good” air since at least 1980. The federal agency’s online data goes back no further, but one expert suspects that L.A.’s air hasn’t been this clean since around the time the United States entered the Second World War. Cody Hill, an energy company executive based in the Bay Area, posted a graphic of the EPA data to his Twitter account and wrote that, in terms of air quality, March may well have been “one of the best months at least since the 1940s, when there was huge migration as we ramped up aircraft production in the L.A. basin to fight WW2.”
Los Angeles had the cleanest air ever recorded there in March 2020. Astounding chart from the EPA.
This is mostly from reduced driving with the same vehicle fleet. It could be the new normal and ~13 million people living there would be healthier if we electrify transportation. pic.twitter.com/WOCcMhcogI
— Cody Hill (@cody_a_hill) April 3, 2020
The notorious L.A. smog starts as a cloud of traffic emissions that’s spewed into the air during the morning rush hour. This layer of air pollution is then held in place by a combination of the Southland’s topography and its prevailing weather patterns, and baked for hours in SoCal’s warm ultraviolet rays, an effect that air-quality experts liken to a pot of soup heating on a stove.
There’s no question that the drastic improvement in air quality—a combined measure of the particle pollution, carbon monoxide, sulfur dioxide, nitrogen dioxide, and ozone we breathe into our lungs—is due to the fact that most Angelenos are driving less and staying inside more. On March 18, L.A.’s infamous rush-hour traffic was moving 71 percent faster than it usually does on a Wednesday afternoon, The New York Times reported. But strong winds and repeated rain showers in March also played a part, says Ed Avol, a professor of clinical preventive medicine at the Southern California Environmental Health Sciences Center at USC.
Avol is in his 60s and grew up in Los Angeles. He has spent decades studying issues of air quality in L.A. as they relate to health. “Certainly the air is a lot cleaner now than when I was a child, but we still have a long way to go to get clean air,” he said. “And these last couple of weeks have shown us that it’s possible, but it’s going to take a lot of hard work to get there.”
The historically low air pollution is an aberration and the smog will return when life goes back to normal, unless, as Avol hopes, telecommuting is here to stay. He believes it has the potential to do for air pollution in the next decade what increasing fuel emissions standards accomplished in the early 2000s.
“It’s obviously very unfortunate that it takes a pandemic to get us to think about these things and to see this improvement. It should give us all pause to think about how much driving we each do, and whether we really need to do so much of it. Telecommuting from home, for those who can, even just for a couple of days a week, can have a marked reduction in terms of emissions.”
“And this experience should make that very clear to people who didn’t think about it before.”