“…Numerous studies using regional CTMs that have considered both changing climate and changing emissions on future air pollutant concentrations have found that changes in emissions dominate (Nolte et al, 2008;Kelly et al, 2012;Colette et al, 2013;Trail et al, 2014;Day and Pandis, 2015;Gonzalez-Abraham et al, 2015;He et al, 2016). Modeled pollutant concentrations are highly sensitive to lateral chemical boundary conditions (e.g., Tang et al, 2007;Katragkou et al, 2010;Schere et al, 2012), and different assumptions regarding changes in long-range transport have been shown to have a significant impact on future pollutant levels (Nolte et al, 2008;Colette et al, 2013;Pfister et al, 2014;Gonzalez-Abraham et al, 2015;He et al, 2016;Zhang et al, 2016). Several previous studies have also highlighted the importance of rising levels of methane for ozone chemistry (Fiore et al, 2002;West and Fiore, 2005;Nolte et al, 2008).…”