With climate change will come air quality changes, but modeling such effects is complicated. For example, higher temperatures should increase amounts of harmful ground-level ozone, while higher humidity could have varying effects on the compound, depending on pollution levels. A new National Center for Atmospheric Research supercomputer helps to factor in such competing effects. The supercomputer enables regional air quality projections that incorporate climate-change effects, as demonstrated in a study of U.S. summertime ozone concentrations between now and 2050 (J. Geophys. Res. Atmos. 2014, DOI: 10.1002/2013jd020932). In that study, a research team found that without new emission controls, climate change would lead to a 70% increase in days exceeding the current EPA standard for ground-level ozone. When the scientists incorporated reduced emissions of ozone precursors NOx, CO, and volatile organic carbon compounds, however, air quality improved compared with today. The results demonstrate the need to combine emissions, climate, and regional influences when considering future air quality, the authors say.