Platform: NOAA-CHEM Twin Otter Instruments

Iodide-based Chemical Ionization Time-of-Flight Mass Spectrometer (I- ToF CIMS)

University of Washington Department of Atmospheric Sciences measurements of Acids (HNO₃, HONO, Organics), acid gases (N₂O₅, ClNO₂), Oxygenated organics, Organic nitrates, Halogens

Measurement Objectives:

• Controls on near-field oxidation, day and night
• Calibrated radical sources: HONO, N₂O₅ (constraint on NO₃), ClNO₂, Cl₂
• Oxidation products: HNO₃, R_iONO₂
• Volatility distribution of organic carbon vapors, its evolution downwind, and variation across fire types and time of day.
• 100s of OVOC covering wide range of volatility space (IVOC, SVOC, LVOC, ELVOC)
• Couplings between reactive nitrogen and organic carbon that affect aerosol evolution and properties
• Semi and low volatility R_iONO₂ from NO₃ + VOC vs RO₂ + NO, aromatic vs BVOC (isoprene, monoterpenes, etc); NO₃ + RC(O)H → HNO₃ + R'
• Light absorbing secondary organic aerosol (SOA) products

Research Team

Joel Thornton

Brett Palm

Carley Fredrickson