Spatio-temporal variability in isotopic signatures of atmospheric NOx emissions from vehicles

David J Miller1, Paul Wojtal1, Mary O'Connor1, Sydney C Clark2 and Meredith Galanter Hastings2, (1)Brown University, Providence, RI, United States, (2)Brown University, Department of Earth, Environmental and Planetary Sciences, and Institute at Brown for Environment and Society, Providence, RI, United States