Modeling comprehensive chemical composition of weathered oil following a marine spill to predict ozone and potential secondary aerosol formation and constrain transport pathways. Issue 11 (9th November 2015)

• Record Type: Journal Article
• Authors: Drozd, Greg T.; Worton, David R.; Aeppli, Christoph; Reddy, Christopher M.; Zhang, Haofei; Variano, Evan; Goldstein, Allen H.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 11(2015:Nov.)
• Page Start: 7300
• Page End: 7315
• Publication Date: 2015-11-09
• Subjects: Deepwater Horizon disaster -- comprehensive gas chromatography with vacuum ultraviolet ionization mass spectrometry -- evaporative oil weathering -- secondary organic aerosol; Oceanography -- Periodicals; 551.4605
• DOI: 10.1002/2015JC011093
• Languages: English
• ISSNs: 2169-9275

Abstract

Abstract: Releases of hydrocarbons from oil spills have large environmental impacts in both the ocean and atmosphere. Oil evaporation is not simply a mechanism of mass loss from the ocean, as it also causes production of atmospheric pollutants. Monitoring atmospheric emissions from oil spills must include a broad range of volatile organic compounds (VOC), including intermediate‐volatile and semivolatile compounds (IVOC, SVOC), which cause secondary organic aerosol (SOA) and ozone production. The Deepwater Horizon (DWH) disaster in the northern Gulf of Mexico during Spring/Summer of 2010 presented a unique opportunity to observe SOA production due to an oil spill. To better understand these observations, we conducted measurements and modeled oil evaporation utilizing unprecedented comprehensive composition measurements, achieved by gas chromatography with vacuum ultraviolet time of flight mass spectrometry (GC‐VUV‐HR‐ToFMS). All hydrocarbons with 10–30 carbons were classified by degree of branching, number of cyclic rings, aromaticity, and molecular weight; these hydrocarbons comprise ∼70% of total oil mass. Such detailed and comprehensive characterization of DWH oil allowed bottom‐up estimates of oil evaporation kinetics. We developed an evaporative model, using solely our composition measurements and thermodynamic data, that is in excellent agreement with published mass evaporation rates and our wind‐tunnel measurements. Using this model, we determine surface slick samples are composed of oil with a distribution of evaporative ages and identify and characterize probable subsurface transport of oil. Key Points: Evaporation of oil is modeled using comprehensive composition derived from GC‐VUV‐MS analysis Modeled surface slick compositions suggest significant subsurface transport of oil during the DWH disaster Oil evaporation, particularly intermediate volatility compounds leads to significant secondary organic aerosol