Table 2. Hydroxyacetone Experiment Conditions in the CESAM Chamber.
|
cloud eventsc |
notes | |||||||
|---|---|---|---|---|---|---|---|---|
| expt. | Figure. | steady-state [HA](g)(ppb)a | seed aerosol typeb | [MeAm](g)(ppb) | [HOOH]max(molec/cm3)a | dark | light | |
| A | S1 | 500 ± 50 | none | 0 | (6 ± 0.04) × 1013 | 0 | 2 | No seeds |
| B | 3 | 30 ± 3d | AS | 0 | 0.8 × 1013 | 1 | 2 | HA(g) + AS(p) seeds |
| C | 4 | 60 ± 6d | AS/glycine | 0 | 5 × 1013 | 1 | 1 | HA(g) + AS/Gly(p) |
| D | 5 | 40 ± 4e | AS/HA | 500 (2×) | 3 × 1013 | 1 | 1 | MeAm(g) + HA/AS(p) |
| E | S2 | 0 | AS | 0 | 0 | 0 | 0 | AS dry blank |
a
Based on PTR-ToF-MS signals at m/z 75 (for HA) or m/z 33 (for HOOH) in dry chamber, calibrated by in situ long-path FTIR absorption in range 1030–1220 cm–1 (for HA) or 1228–1258 cm–1 (for HOOH) using reference spectra from the AERIS database.31
b
Atomizer-generated and diffusion-dried before added to chamber.
c
Runs A-D included 2–3 cloud events each, with “light” indicating cloud event(s) for which solar simulator lights were turned on.
d
Higher levels were briefly observed upon HA(g) addition under dry conditions, before humidification.
e
HA released to the gas phase from aerosol particles. Abbreviations: [HOOH]max, maximum hydrogen peroxide concentration; (g), gas; (p), particulate.