Improving our understanding of aerosol formation, transformation and lifetime in controlled atmospheres

Quantifying the partitioning of molecular constituents between the gas and vapour phases is important for understanding aerosols in a broad range of contexts including air quality and the unintentional, intrinsic, or intentional release of material. These might include the biogenic emissions of organic components in a boreal forest, anthropogenic emissions of vapours and particles from cars and the release of vapours and particles from explosive materials, respectively.

Not only does phase partitioning govern aerosol particle mass concentrations and size distributions, but it governs the transport of material away from source, and the lifetime and rates of chemical processing and degradation of the source material. Most importantly, this partitioning is dependent on the temperature-dependent vapour pressures of the molecular constituents, their mixing with other aerosol constituents, and the dependence of the partitioning on environmental conditions such as relative humidity (RH).

The detection and identification of explosives by analytical techniques usually relies on the detection of components in the vapour phase or as trace solids. For example, vapour phases can be sampled in sorption tubes for subsequent off-line analysis using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). For quantification of trace explosive components, this approach relies on a transference of a complete gaseous sample and neglects the potential for transport and concentration by aerosol in ambient particles prior to collection.

This project will improve our understanding of the gas-particle phase partitioning of semi-volatile trace explosive components and the potential to use aerosols to provide increased sampling sensitivity.