Amid a rainy March in which millions of Angelenos observed orders to stay at home, sight lines in the city got clearer and the region’s notorious smog was nowhere to be found.

For nearly the entire month of March, air quality maps tracking the region’s scores on the Environmental Protection Agency’s Air Quality Index were nothing but green—the color that denotes the cleanest air.

Historical data from the EPA suggests that it may have been the longest stretch of clean air since 1980, the earliest year with available data.

March had 24 days—including 20 days in a row—with a daily air quality score below 50, denoting air that’s healthy even for people sensitive to pollution (those with respiratory issues or heart problems, for instance). March 2019 had 14 such days—the highest number for the month since 2006. In March 2008, LA County’s air quality score fell below 50 just once.

“We’re seeing very clean air all around California,” says Bill Magavern, policy director with the Coalition for Clean Air. “This time of year we usually have better air, especially with the rain, but the drop-off in traffic has definitely reduced emissions.”

It’s a small silver lining to a pandemic that’s shut down businesses, closed schools, and put strain on LA’s healthcare system.

Magavern points out that this could even aid those afflicted with COVID-19, the disease caused by the novel coronavirus. The European Public Health Alliance warned last week that residents of cities with poor air quality are “more at risk” from the disease, which can cause severe respiratory issues.

According to the California Air Resources Board, the last time ozone (a major contributor to smog) in the Los Angeles area reached unhealthy levels was in February. Over the summer, the region saw unhealthy ozone levels every day for more than two straight months.

Still, Magavern says, a global pandemic is not a worthy trade for cleaner air.

“This is not the way we want to reduce emissions,” he says.

The coalition has long advocated for policies aimed at reducing greenhouse gases caused by transportation—the largest source of emissions in California. Those include incentives to get more drivers to switch to electric vehicles, or simply stop driving so often.

“This is a reminder that the vast majority of our air pollution comes from the transportation of people and goods,” Magavern says.

In 19 of the last 20 years, the American Lung Association named Los Angeles the smoggiest metropolitan area in the United States. Traffic analyst Inrix recently found the city’s traffic congestion to be the sixth-worst in the nation.

As a measure of how much that traffic congestion has dissipated, Inrix found that cars were moving 63 percent faster than average at 5:30 p.m. last Tuesday.

Romel Pascual, director of open streets festival organizer CicLAvia, says he’s hoping that Angelenos use this time stuck at home to rediscover their own neighborhoods. Though local officials have ordered residents not to leave the house except for essential needs, walking and outdoor exercise has been encouraged—so long as people aren’t doing it in groups.

“I’m walking in my neighborhood more than ever before,” he says. “I’m noticing a lot more folks walking. You don’t have to go some [other] place to experience the environment; you can listen to the birds flying by and look at the trees almost anywhere.”

Bryn Lindblad, deputy director of Climate Resolve, says she’s hopeful people will be able to retain some of the habits they develop during this time.

“It’s ironic to me that it’s a quarantine order that’s getting people to do what public health experts have been advising for years—walking around the neighborhood,” she says. “I’m hoping people hold on to that a little bit. After this whole rigmarole is over, we can still keep our streets nice and inviting to people.”