Study of Aerosols and Volatile Organic Compounds During a Long-range Transport Biomass Burning Event

Long-range transport of biomass burning (BB) can significantly impact the local air quality of a region including Texas. During a 2021 springtime field campaign near Corpus Christi, Texas a BB event was characterized through a series of real-time (a) volatile organic compounds (VOCs) measured with a proton transfer reaction mass spectrometer (PTR-MS), (b) aerosol optical properties using Tricolor absorption photometer (TAP) and nephelometer, (c) submicron aerosol speciation using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and (d) trace gas measurements (CO, NOx, CO2 and O3). Throughout the BB event, abundances of biomass burning tracer VOCs were enhanced including acetonitrile and acetaldehyde (average concentrations of 0.31 ± 0.13 ppbv and 4.59 ± 1.47 ppbv respectively). Anthropogenic VOCs- benzene and toluene were also elevated during the biomass burning event with average concentrations of 0.55 ± 0.19 ppbv and 0.94 ± 0.40 ppbv respectively. Absorption coefficients (abs) exceeded 10 Mm-1 at 365 nm while the absorption Angstrom exponent (AAE) was above 1.2 during the studied period; these parameters suggested influence of biomass burning as they were elevated above the coastal background conditions. An elevated organic aerosol and a levoglucosan signal (f60) measured by AMS during the studied period also confirmed the biomass burning influence. All these indicators were highlighted strongly against the clean marine boundary layer conditions that preceded the event. Analysis of back trajectories, spatial distribution of smoke cover retrieved from NOAA Fire and Hazard Maps, and VIIRS fire spots indicated transport of biomass burning airmass over the Gulf of Mexico from potential source regions in Mexico and Central America. These biomass burning plumes would have undergone processing during transport including dilution, oxidation, and bleaching which would impact aerosol and gas phase composition as well as aerosol optical properties. Discussion of processing during transport will be presented during the conference.