Emissions of C-6-C-8 aromatic compounds in the United States: Constraints from tall tower and aircraft measurements

Details

• Journal Title:
  Journal of Geophysical Research: Atmospheres
• Personal Author:
  Hu, Lu ; Millet, Dylan B. ; Baasandorj, Munkhbayar ; Griffis, Timothy J. ; Travis, Katherine R. ; Tessum, Christopher W. ; Marshall, Julian D. ; Reinhart, Wesley F. ; Mikoviny, Tomas ; Müller, Markus ; Wisthaler, Armin ; Graus, Martin ; Warneke, Carsten ; de Gouw, Joost
• NOAA Program & Office:
  OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory)
• Description:
  We present two full years of continuous C-6-C-8 aromatic compound measurements by PTR-MS at the KCMP tall tower (Minnesota, US) and employ GEOS-Chem nested grid simulations in a Bayesian inversion to interpret the data in terms of new constraints on US aromatic emissions. Based on the tall tower data, we find that the RETRO inventory (year-2000) overestimates US C-6-C-8 aromatic emissions by factors of 2.0-4.5 during 2010-2011, likely due in part to post-2000 reductions. Likewise, our implementation of the US EPA's NEI08 overestimates the toluene flux by threefold, reflecting an inventory bias in non-road emissions plus uncertainties associated with species lumping. Our annual top-down emission estimates for benzene and C-8 aromatics agree with the NEI08 bottom-up values, as does the inferred contribution from non-road sources. However, the NEI08 appears to underestimate on-road emissions of these compounds by twofold during the warm season. The implied aromatic sources upwind of North America are more than double the prior estimates, suggesting a substantial underestimate of East Asian emissions, or large increases there since 2000. Long-range transport exerts an important influence on ambient benzene over the US: on average 43% of its wintertime abundance in the US Upper Midwest is due to sources outside North America. Independent aircraft measurements show that the inventory biases found here for C-6-C-8 aromatics also apply to other parts of the US, with notable exceptions for toluene in California and Houston, Texas. Our best estimates of year-2011 contiguous US emissions are 206 (benzene), 408 (toluene), and 822 (C-8 aromatics) GgC.
• Source:
  Journal of Geophysical Research-Atmospheres, 120(2), 826-842.
• DOI:
  https://doi.org/10.1002/2014jd022627
• Document Type:
  Journal Article
• Rights Information:
  Other
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha256:7b064ecff32578688caedc2a8f7bd423a9b22bf8ff821c849f9a211822862454
• Download URL:
  https://repository.library.noaa.gov/view/noaa/21627/noaa_21627_DS1.pdf
• File Type:
  [PDF - 1.59 MB ]