“This is a really good experiment that we hope will never be repeated again,” he said. But as the shutdown cleared cars off the roads and brought factories to a halt, coal plants and cookstoves kept emitting. That allowed Dr. Guttikunda and his colleagues to develop a more precise profile of pollution, source by source, city by city, region by region. “If you want to clean up your air pollution problem, you have to know what to target,” he said. “This is a theory that atmospheric chemists learn in class, but we haven’t seen it work in real time,” said Dr. Guttikunda.

Source: New York Times June 25, 2020 15:18 UTC