title: Changes in inorganic fine particulate matter sensitivities to precursors due to large-scale US emissions reductions.
abstract: We examined the impact of large US emissions changes, similar to those estimated to have occurred between 2005 and 2012 (high and low emissions cases, respectively), on inorganic PM2.5 sensitivities to further NOx, SO2, and NH3 emissions reductions using the chemical transport model GEOS-Chem. Sensitivities to SO2 emissions are larger year-round and across the US in the low emissions case than the high emissions case due to more aqueous-phase SO2 oxidation. Sensitivities to winter NOx emissions are larger in the low emissions case, more than 2× those of the high emissions case in parts of the northern Midwest. Sensitivities to NH3 emissions are smaller (∼40%) in the low emissions case, year-round, and across the US. Differences in NOx and NH3 sensitivities indicate an altered atmospheric acidity. Larger sensitivities to SO2 and NOx in the low emissions case imply that reducing these emissions may improve air quality more now than they would have in 2005; conversely, NH3 reductions may not improve air quality as much as previously assumed.
authors: †Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 54-1711, Cambridge, Massachusetts 02139, United States.
authors: Jareth
authors: J
authors: Holt
authors: †Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 54-1711, Cambridge, Massachusetts 02139, United States.|‡Engineering Systems Division, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
authors: Noelle E
authors: NE
authors: Selin
authors: †Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Building 54-1711, Cambridge, Massachusetts 02139, United States.
authors: Susan
authors: S
authors: Solomon
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring; D008962:Models, Theoretical; D009589:Nitrogen Oxides / Q000032:analysis; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D013458:Sulfur Dioxide / Q000032:analysis; D014481:United States
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D013458:Sulfur Dioxide