Ambient concentrations of polycyclic aromatic hydrocarbons (PAHs) were measured in Helsinki (Finland). Particle mass size distributions were obtained with a cascade impactor (12 stages) with glass fibre filters as substrates. Simultaneously with the impactor measurements, particulate and gaseous PAHs were collected on a quartz filter and XAD-2 adsorbent, respectively, for evaluation of gas-partition coefficients. Samples s were analysed for PAHs by on-line coupled supercritical fluid extraction - liquid chromatography - gas chromatography - mass spectrometry. The impactor results showed that most of the PAHs in Helsinki urban area were concentrated in fine particles (<2.5 μm diameter) with unimode peak at about 1 μm. The results were comparable with the number distribution measured with a differential mobility particle sizer. Total amounts of PAHs (gas + particle) varied from 15 (acenaphthylene) to 1990 (fluorene) pg/m3. The PAHs lighter than 202 amu (pyrene and fluoranthene) were exclusively in gas phase, whereas those heavier than 202 amu were mostly associated with particles. A plot of the partition coefficients (logKp) versus the temperature dependent sub-cooled vapour pressures (logp0L) showed a gradient of -0.66, which deviated from equilibrium state (gradient = -1). © 2004 Kluwer Academic Publishers.
CITATION STYLE
Shimmo, M., Saarnio, K., Aalto, P., Hartonen, K., Hyötyläinen, T., Kulmala, M., & Riekkola, M. L. (2004). Particle size distribution and gas-particle partition of polycyclic aromatic hydrocarbons in Helsinki Urban Area. Journal of Atmospheric Chemistry, 47(3), 223–241. https://doi.org/10.1023/B:JOCH.0000021088.37771.f7
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