Environment

Did Covid Lockdowns Really Clear the Air?

City residents marveled at smog-free skies as car traffic plummeted in the early days of the coronavirus pandemic. But some forms of air pollution remained stubbornly high.  

A rare sight emerged for L.A. residents in April 2020: the snow-capped peaks of the San Gabriel mountains, clearly visible in the smog-free atmosphere.  

Photographer: David McNew/Getty Images North America

The early days of the Covid-19 lockdowns were seen as an environmental marvel. With fewer commuters and empty highways, residents of cities from Los Angeles to New Delhi witnessed clear blue skies and mountain views that had long been obscured by smog. The dramatic atmospheric transformation was one of first of the “silver linings” that the coronavirus pandemic was said to deliver.

For scientists, the clear skies of the lockdown presented a unique opportunity: a real-life glimpse at a world where a major source of pollution could be removed. Researchers around the world harnessed just about every monitoring device possible to study this natural air quality experiment, which could offer a preview of a world where electric vehicles have knocked out tailpipe pollution.