Expt. B with gas-phase hydroxy-acetone, photolysis, cloud
processing,
and HOOH oxidation with AS seed particles in the CESAM chamber. HA
addition, two water vapor additions, start of chamber illumination,
start of continuous HOOH addition, and 3 cloud events are labeled.
Panel a: total organic carbon readings and mass absorption
coefficients at 365 nm from PILS/waveguide UV–vis, color coded
to axes. b: chamber RH and droplet spectrometer counts,
color coded to axes. c: water-corrected PTR-ToF-MS data
(m/z 75 HA, red line; m/z 33 HOOH, blue line). d: Dilution-
and wall-loss-corrected SMPS aerosol total mass (assuming density
= 1 g cm–3) and counts, color-coded to axes. e: CAPS-ssa data at 450 nm (mass-corrected extinction, blue
line; mass-corrected scattering, black line; single-scattering albedo,
red dots; albedo measured immediately after instrument autozero to
remove contributions from gas-phase absorbers, red triangles.