Background nitrogen dioxide (NO2) over the United States and its implications for satellite observations and trends: effects of nitrate photolysis, aircraft, and open fires
Ruijun Dang,Daniel J. Jacob,Viral Shah,Sebastian D. Eastham,Thibaud M. Fritz,Loretta J. Mickley,Tianjia Liu,Yi Wang,and Jun Wang
Department of
Aeronautics and Astronautics, Laboratory for Aviation and the Environment, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Joint Program on the Science and Policy of Global Change,
Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Department of
Aeronautics and Astronautics, Laboratory for Aviation and the Environment, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Loretta J. Mickley
John A. Paulson School of Engineering and Applied Sciences, Harvard
University, Cambridge, MA 02138, USA
Tianjia Liu
Department of Earth and Planetary Sciences, Harvard University,
Cambridge, MA 02138, USA
Yi Wang
Center for Global and Regional Environmental Research, Iowa
Technology Institute, The University of Iowa, Iowa City, IA 52242, USA
Department of Chemical and Biochemical Engineering, The University of
Iowa, Iowa City, IA 52242, USA
We use the GEOS-Chem model to better understand the magnitude and trend in free tropospheric NO2 over the contiguous US. Model underestimate of background NO2 is largely corrected by considering aerosol nitrate photolysis. Increase in aircraft emissions affects satellite retrievals by altering the NO2 shape factor, and this effect is expected to increase in future. We show the importance of properly accounting for the free tropospheric background in interpreting NO2 observations from space.
We use the GEOS-Chem model to better understand the magnitude and trend in free tropospheric NO2...