Experiment Set: ALPACA chamber experiments

Experiment Set: ALPACA chamber experiments
Name: ALPACA chamber experiments
Time format and units: HH:MM

Nguyen Group


Tran's big bag of air

A series of experiments targeted at quantifying oxidant production and S(IV)-->S(VI) conversion in the particles samples in Fairbanks, AK during the ALaskan Pollution And Chemical Analysis (ALPACA) campaign (winter 2022). The first several experiments in this set are designed to better characterize our chamber and the behavior of Fairbanks-like particles; this includes quantifying dark/light H2O2 loss rates, SO2 loss rates, wall loss rates of atomized particles (including a gallic acid / ellagic acid solution designed to promote 3C* formation, and a solution of wood smoke particles made from burning dried oak in a control chamber), and measuring interactions between the aforementioned particles, H2O2, and SO2 in dark and light conditions. In the later experiments, actual filter samples of particles collected in Fairbanks during ALPACA were extracted in water and these extracts were atomized into the chamber for direct measurement. In some cases, chemical probes were added to the atomizing solutions so that they could then be measured offline from filter samples taken after chamber experiments to determine in-particle formation of 3C*, 1O2, and OH during the experiment. Online measurements included here include CF3O- CIMS for gas-phase acids, polar organics, and crucially H2O2 and SO2; SMPS for particle size distributions; RH/T; O3 chemiluminescence; and occasional NOx monitoring, although for many experiments the NOx monitor was not properly recording data, in which case NOx readings are noted in the experiment descriptions.


  • Cort Anastasio (UC Davis)


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Experiments (9)

ID Name Start date Experiment Category Reaction Type Reactant(s) Oxidant Name Temperature Humidity Type of Seed RO2 Main Fate Data Sets (count) Actions