NASA helps map impact of COVID-19 lockdowns on harmful air pollution
Early in the pandemic, it was expected that satellite imagery around the world would show cleaner air as a result of COVID-19 lockdowns. But not all pollutants were taken out of circulation. For tiny airborne-particle pollution, known as PM 2.5, researchers using NASA data found that variability from meteorology obscured the lockdown signals when observed from space.
"Intuitively you would think if there is a major lockdown situation, that we would see dramatic changes, but we didn't," said Melanie Hammer, a visiting research associate at Washington University in St. Louis who led the study. "It was kind of a surprise ...








