Year: 2024
Type: article
Abstract: Using a new approach that constrains thermodynamic modeling of aerosol composition with measured gas-to-particle partitioning of inorganic nitrate, we estimate the acidity levels for aerosol sampled in the South Korean planetary boundary layer during the NASA/NIER KORUS-AQ field campaign. The pH (mean ± 1σ = 2.43±0.68) and aerosol liquid water content determined were then used to determine the 'chemical regime' of the inorganic fraction of particulate matter (PM) sensitivity to ammonia and nitrate availability. We found that the aerosol formation is always sensitive to HNO3 levels, especially in highly polluted regions, while it is only exclusively sensitive to NH3 in some rural/remote regions. Nitrate levels are further promoted because dry deposition velocity is low and allows its accumulation in the boundary layer. Because of this, HNO3 reductions achieved by NOX controls prove to be the most effective approach for all conditions examined, and that NH3 emissions can only partially affect PM reduction for the specific season and region. Despite the benefits of controlling PM formation to reduce ammonium-nitrate aerosol and PM mass, changes in the acidity domain can significantly affect other processes and sources of aerosol toxicity (e.g. solubilization of Fe, Cu and other metals) as well as the deposition patterns of these trace species and reactive nitrogen.
Authors: Ifayoyinsola Ibikunle, Andreas Beyersdorf, Pedro Campuzano-Jost, Chelsea Corr, John D. Crounse, Jack Dibb, Glenn Diskin, Greg Huey, Jose-Luis Jimenez, Michelle J. Kim, Benjamin A. Nault, Eric Scheuer, Alex Teng, Paul O. Wennberg, Bruce Anderson, James Crawford, Rodney Weber, Athanasios Nenes
Institutions: Georgia Institute of Technology, Langley Research Center, National Aeronautics and Space Administration, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Colorado State University, California Institute of Technology, University of New Hampshire, Ames Research Center, Aerodyne Research, École Polytechnique Fédérale de Lausanne, Foundation for Research and Technology Hellas
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: diamond
Funders: National Science Foundation, National Aeronautics and Space Administration, California Institute of Technology, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Nuclear Safety and Security Commission, Langley Research Center, Horizon 2020 Framework Programme, H2020 Excellent Science, HORIZON EUROPE Excellent Science
Awards: G2323052408, G2615899351, ORGANIC AEROSOL (OA) IS A MAJOR CONTRIBUTOR BY MASS TO THE GLOBAL SUBMICRON AEROSOL BURDEN. HOWEVER, DESPITE BEING UBIQUITOUS THROUGHOUT THE TROPOSPH, AN AIRBORNE INVESTIGATION OF AEROSOL AND CLOUD PROPERTIES IN SUPPORT OF KORUS-AQ GEORGIA INSTITUTE OF TECHNOLOGY WILL PROVIDE A GRAD STUDENT (AND IF, G4386793436, Atmospheric Acidity Interactions with Dust and its Impacts (AAIDI), G4924830786, G5692014976, THE KORUS AQ MISSION WILL ADDRESS THE PHYSICS AND CHEMISTRY THAT TIE THE COMPOSITION OF THE TROPOSPHERE TO THE RAPIDLY CHANGING EMISSIONS IN ASIA. WE, G696676437, FIRES ARE ONE OF THE MAIN CONTRIBUTORS TO THE GLOBAL FINE AEROSOL BURDEN ESPECIALLY FOR ORGANIC AEROSOL (OA) AND ITS OPTICALLY ACTIVE FRACTION BROWN CARBON (BRC) BUT ALSO FOR INORGANIC SPECIES. CHANGES IN LAND USE PATTERNS AS WELL AS A CHANGING CLIMATE ARE EXPECTED TO SIGNIFICANTLY INCREASE THE PREVALENCE OF FIRES AND HENCE THEIR AEROSOL EMISSIONS IN THE US AS WELL AS GLOBALLY. HOWEVER THE EMISSIONS OF PRIMARY AEROSOL AND GASEOUS AEROSOL PRECURSORS FROM FIRES AND THEIR SUBSEQUENT ATMOSPHERIC EVOLUTION ARE STILL POORLY UNDERSTOOD. THERE IS HIGH VARIABILITY IN EMISSION RATIOS AND THE OXIDATIVE EVOLUTION OF OA AMONG INDIVIDUAL FIRES IN FIELD AND LABORATORY STUDIES AND HENCE NOT SURPRISINGLY IN GLOBAL MODELS. AS PART OF NASA FIRECHEM THE PROPOSED WORK WILL ADDRESS THE FOLLOWING OBJECTIVES: (A) QUANTIFY THE PRIMARY OA (POA) AND INORGANIC EMISSIONS FROM AGRICULTURAL AND WILD FIRES. THE VOLATILITY OF POA A CRITICAL BUT POORLY UNDERSTOOD PROPERTY THAT AFFECTS AGING WILL BE DIRECTLY QUANTIFIED BY THERMAL DENUDING AS WE DEMONSTRATED IN KORUSAQ AND WINTER. THE RELATIONSHIP BETWEEN EMISSION RATIOS AND FIRE PROPERTIES (INCLUDING MODIFIED COMBUSTION EFFICIENCY MCE) INCLUDING THE NATURE AND VARIABILITY OF THE MOLECULAR AEROSOL COMPOSITION WILL BE INVESTIGATED. (B) STUDY THE EVOLUTION OF THE MASS AND COMPOSITION OF OA AND INORGANIC AEROSOLS DOWNWIND OF FIRES INCLUDING SECONDARY OA (SOA) FORMATION OA OXIDATION AND THEIR VARIABILITY. THE REASONS WHY SOA FORMATION IS OFTEN LOW IN FIELD STUDIES COMPARED TO LARGER FORMATION IN LABORATORY STUDIES WILL BE INVESTIGATED. PRECURSORS AND FIRST-GENERATION PRODUCTS THAT DRIVE OXIDATION OF POA AND SOA FORMATION FROM FIRES WILL BE IDENTIFIED. THE EVOLUTION OF AEROSOL VOLATILITY AND THE IMPACT OF OA EVAPORATION ON TOTAL OA EVOLUTION WILL ALSO BE QUANTIFIED. (C) IDENTIFY MOLECULAR MARKERS IN OA THAT ARE CORRELATED WITH MEASURED BRC LIGHT ABSORPTION AND USE THEM TO INVESTIGATE THE SPECIES RESPONSIBLE FOR PRIMARY BRC AS WELL AS THE POSSIBLE CHEMICAL PATHWAYS FOR BLEACHING OR FORMATION OF BRC DOWNWIND OF FIRES. THE PROPOSED WORK USES A COMBINED INSTRUMENTAL APPROACH TO CHARACTERIZE AND QUANTIFY THE BULK PROPERTIES OF OA AS WELL AS THEIR MOLECULAR CHEMISTRY BOTH AT THE HIGH TIME RESOLUTION REQUIRED FOR MEASUREMENTS NEAR FAST CHANGING SOURCES SUCH AS FIRES: (1) A HIGHLYCUSTOMIZED AERODYNE HIGH-RESOLUTION AEROSOL MASS SPECTROMETER (AMS) THAT HAS MULTIPLE UNIQUE PERFORMANCE ADVANTAGES VS. OTHER AIRCRAFT AMSS. THIS INSTRUMENT WILL QUANTIFY NON-REFRACTORY INORGANIC AEROSOLS AND OA MASS (BOTH BULK AND SIZE SEGREGATED) AS WELL OA PROPERTIES (O/C H/C OSC OA/OC) WITH SAMPLING RATES UP TO 10 HZ (TYPICALLY 1 HZ). (2) A RECENTLY-DEVELOPED INSTRUMENT THE EESI-TOF-MS USING EXTRACTIVE ELECTROSPRAY IONIZATION (THUS AVOIDING THERMAL DECOMPOSITION ARTIFACTS) WILL CHARACTERIZE A LARGE NUMBER OF MOLECULAR COMPONENTS OF OA (INCLUDING E.G. LEVOGLUCOSAN) AT 1 HZ RESOLUTION ALLOWING LINKING BULK AND MOLECULAR-LEVEL OA CHEMISTRY FROM AIRCRAFT FOR THE FIRST TIME. OF PARTICULARLY HIGH INTEREST ARE N-CONTAINING COMPOUNDS PRODUCTS OF OH OXIDATION OF KEY GAS-PHASE PRECURSORS AND PRODUCTS OF OLIGOMERIZATION. THESE RESULTS WILL LEAD TO MORE ROBUST PARAMETRIZATIONS OF THE PRIMARY EMISSIONS FROM FIRES IN PARTICULAR SMALL AGRICULTURAL FIRES WHERE AMBIENT DATA IS SCARCE. THEY WILL ALSO SYSTEMATICALLY ADDRESS WHICH FIRE PROPERTIES AND SPECIES CONTROL OA FORMATION EVAPORATION AND OXIDATION BY TYING TOGETHER BULK OA AND MOLECULAR TRACERS. THIS WORK WILL BE CONDUCTED IN CLOSE COLLABORATION WITH THE NOAA AMS AND UW EESI TEAMS ON THE NOAA P3 AIRCRAFT AS PART OF THE FIRECHEM/FIREX COLLABORATION. THE CONSISTENT AND COORDINATED PAYLOAD ON BOTH AIRCRAFT WILL GREATLY FACILITATE COMBINED USE OF DATA FROM BOTH PLATFORMS. THIS WILL INCLUDE JOINT CALIBRATIONS AND TESTS WITH STANDARDS AND FRESH AND AGED SMOKE SAMPLES FROM DIFFERENT FUELS AT THE CU-BOULDER ENVIRONMENTAL CHAMBER FACILITY., G8866374800, G8974894827
OpenAlex ID: W4404730520