Volatility of secondary organic aerosols from the ozone initiated oxidation of α-pinene and limonene

The volatility of secondary organic aerosol (SOA) from the ozone initiated oxidation of a-pinene and limonene has been investigated in a large aerosol chamber facility, the AIDA chamber of Research Centre Karlsruhe, by using a volatility tandem-DMA system (VTDMA). The volatility of particles has been classified by monitoring the change in particle peak diameter at temperatures between 298 and 583 K. Specifically, the volatility of SOA was determined depending on organic precursor molecule, temperature at which the SOA was formed (243-303 K), relative humidity (0.2-72% RH), size of the particles (20-300 nm), and the presence of an OH-scavenger. Depending on experimental conditions the normalised mode particle diameter e.g. at an evaporative temperature of 423 K ranged from 0.32 to 0.65, i.e. remaining volume fraction 0.04-0.27. The thermal characteristics of SOA are influenced the most by reaction temperature and organic precursor. In this paper the benefits of using a VTDMA for mechanistic studies of SOA formation is demonstrated. (c) 2007 Elsevier Ltd. All rights reserved.