News release: “Springtime air pollution from Asia, swept across the Pacific Ocean on winds, can contribute to episodes of high surface ozone pollution in the western United States, according to a new study by NOAA scientists and academic colleagues. Several recent studies have shown that powerful spring winds can carry Asian pollution into the atmosphere above North America. The new analysis goes further, using high-resolution models and observations to show how some of the imported pollution can descend to the surface, where it affects ground-level ozone, a regulated pollutant. At high concentrations, ground-level ozone can cause severe respiratory effects in some people, and it damages crops, trees, and other vegetation.”