We have participated in several field studies inside and downwind of major metropolitan areas (Boston, New York City, Mexico City, Los Angeles) that allowed the characterization of urban VOC emissions. We developed analysis methods that allow the effects of direct emissions, chemical removal and formation to be separated based on the concept of photochemical age. It was found that urban VOC emissions are not always well represented in emissions inventories. The long-term decline in urban VOC emissions was documented. It has also been found that VOC emissions from motor vehicles, which were historically the largest source of VOCs in urban air, have now been reduced to a point where other VOC sources dominate, such as those associated with the use of volatile chemical products.

Collaborators

Jessica Gilman, Paul Goldan, Brian McDonald, Carsten Warneke (NOAA & CIRES), Agnes Borbon (Univ. Clermont Ferrand), Elliot Atlas (Univ. Miami), Don Blake (UC Irvine)

Key Publications

• Warneke, C., de Gouw, J. A., Holloway, J. S., Peischl, J., Ryerson, T. B., Atlas, E. L., Blake, D. R., Trainer, M. and Parrish, D. D.: Multi-year trends in volatile organic compounds in Los Angeles, California: five decades of decreasing emissions, J. Geophys. Res.-Atmos., 117, D00V17, doi:10.1029/2012JD017899, 2012.
• de Gouw, J. A., Gilman, J. B., Kim, S.-W., Lerner, B. M., Isaacman-VanWertz, G. A., McDonald, B. C., Warneke, C., Kuster, W. C., Lefer, B. L., Griffith, S. M., Dusanter, S., Stevens, P. S. and Stutz, J.: Chemistry of Volatile Organic Compounds in the Los Angeles Basin: Nighttime Removal of Alkenes and Determination of Emission Ratios, J. Geophys. Res.-Atmos., 122, 11843–11861, doi:10.1002/2017JD027459, 2017.
• McDonald, B. C., de Gouw, J. A., Gilman, J. B., Jathar, S. H., Akherati, A., Cappa, C. D., Jimenez, J. L., Lee-Taylor, J., Hayes, P. L., McKeen, S. A., Cui, Y., Kim, S.-W., Gentner, D. R., Isaacman-VanWertz, G. A., Goldstein, A. H., Harley, R. A., Frost, G., Roberts, J. M., Ryerson, T. B. and Trainer, M.: Volatile Chemical Products Emerging as Largest Petrochemical Source of Urban Organic Emissions, Science, 359, 760–764, doi:10.1126/science.aaq0524, 2018.