Anthropogenic emissions of highly reactive volatile organic compounds inferred from oversampling of OMI HCHO columns

Friday, 19 December 2014
Lei Zhu1, Daniel J. Jacob2, Loretta J. Mickley1, Eloise A Marais1, Daniel S Cohan3, Yasuko Yoshida4, Bryan N Duncan5, Gonzalo Gonzalez Abad6 and Kelly Chance7, (1)Harvard University, Cambridge, MA, United States, (2)Harvard University, School of Engineering and Applied Sciences, Cambridge, MA, United States, (3)Rice University, Houston, TX, United States, (4)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (5)NASA GSFC, Greenbelt, MD, United States, (6)Center for Astrophysics, Cambridge, MA, United States, (7)Harvard-Smithsonian, Cambridge, MA, United States
Satellite observations of formaldehyde (HCHO) columns provide top-down constraints on emissions of highly reactive volatile organic compounds (HRVOCs). This approach has been used previously to constrain emissions of isoprene from vegetation, but application to US anthropogenic emissions has been stymied by lack of a discernable HCHO signal. Here we show that oversampling of HCHO data from the Ozone Monitoring Instrument (OMI) for 2005–2008 enables quantitative detection of urban and industrial plumes in eastern Texas including Houston, Port Arthur, and Dallas/Fort Worth. By spatially integrating the individual urban/industrial HCHO plumes observed by OMI we can constrain the corresponding HCHO-weighted HRVOC emissions. Application to the Houston plume indicates a HCHO source of 260±110 kmol h-1 and implies a factor of 5.5±2.4 underestimate of anthropogenic HRVOC emissions in the US Environmental Protection Agency inventory. This approach allows us to monitor trends in HRVOC emissions over the US, in particular from the urban areas and oil/gas industry.