jp066293l_si_001.pdf (47.27 kB)
Photochemical Aging of Secondary Organic Aerosol Particles Generated from the Oxidation of d-Limonene
journal contribution
posted on 2007-03-15, 00:00 authored by Maggie L. Walser, Jiho Park, Anthony L. Gomez, Ashley R. Russell, Sergey A. NizkorodovSecondary organic aerosol (SOA) particles are generated by reacting d-limonene vapor and ozone in a Teflon
reaction chamber. The reaction is carried out in either dry or humid air in darkness. The resulting SOA
particles are collected on glass fiber filters, and their photochemical properties are probed using a combination
of UV photodissociation action spectroscopy and absorption spectroscopy techniques. Photolysis of limonene
SOA in the tropospheric actinic region (λ > 295 nm) readily produces formic acid and formaldehyde as
gas-phase products. The UV wavelength dependence of the photolysis product yield suggests that the primary
absorbers in SOA particles are organic peroxides. The relative humidity maintained during SOA particle
growth is found to have little effect on the UV wavelength dependence of the photolysis product yield. The
data suggest that direct photodissociation processes may play an important role in photochemical processing
of atmospheric SOA particles.