PASADENA, Calif. - As the coronavirus pandemic slowed global commerce to a crawl in early 2020, emissions of nitrogen oxides -- which create ozone, a danger to human health and climate -- decreased 15% globally, with local reductions as high as 50%, according to a study published today, led by scientists at NASA's Jet Propulsion Laboratory.As a result of the lower NOx emissions, by June 2020, global ozone levels had dropped to a level that policymakers thought would take at least 15 years to reach by conventional means, such as regulations.The study shows that innovative technologies and other solutions intended to decrease NOx locally have the potential to rapidly improve air quality and climate globally.