ICARUS Chamber Experiment: Nguyen Group_20220520_Nitrogen Dioxide / Ammonium Sulfate / Ozone / Hydrogen Peroxide / alpha-Pinene Nitrate radical Ammonium sulfate

Goals: To quantify SOA yield and gas-phase product yields (particularly of C10 nitrooxy-hydroperoxide and other organonitrates) from humid nighttime RO2+HO2-dominated NO3-initiated chemistry of a-pinene.Summary: The chamber was humidified, after which H2O2, NO2, and O3 were injected in the chamber and allowed to equilibrate, forming NO3 and HO2. Ammonium sulfate seed particles were injected. Then a-pinene was injected and decayed by simultaneous reaction with ozone and NO3. Gas phase organics were monitored by CF3O- CIMS (units: normalized counts), particle formation was monitored by SMPS, and RH / T / O3 / NOx were monitored throughout.O3/NOx data sometimes require post-correction not applied here, including subtraction of an ozone interference from H2O2 (1 ppm H2O2 is detected as about 12 ppb ozone) and correction for an in-line HEPA filter (see timeline for applicable timing) that scrubs about 10% of NO2 and 45% of ozone.CIMS was periodically stopped during this experiment to retune.Organization: Nguyen Group Lab Affiliation: UC Davis Chamber: Tran's big bag of airExperiment Category: Gas phase chemical reaction, Aerosol formation Oxidant: Nitrate radical Reactants: Nitrogen Dioxide, Ammonium Sulfate, Ozone, Hydrogen Peroxide, alpha-Pinene Reaction Type: Dark oxidation Relative Humidity: 66 Temperature: 22 Seed Name: Ammonium sulfate Pressure: approximate 1 atm