Atmospheric wet and dry deposition of polycyclic aromatic hydrocarbons (PAHs) determined using a modified sampler

Wet and dry deposition samples were collected along with the ambient air samples between September 2008 and June 2009 in an urban site, BUTAL, Turkey. A modified deposition sampler was used for dry and wet periods. Average dissolved and particle phase wet deposition flux values were determined to be 7.4 ± 7.3 μg/m2 day and 21 ± 30 μg/m2 day, respectively. The highest PAH wet fluxes were observed in the winter and fall seasons. Dissolved and particle phase rainwater concentrations of PAHs were 290 ng/L and 665 ng/L. The average of total (particle + gas) atmospheric concentration of ∑12PAH was 130 ± 160 ng/m3. In general, percentages of PAHs with five or more aromatic rings were bigger in particle phase in air. Average washout ratios of PAH compounds were determined 8.97 × 105 and 8.52 × 105 for gas and particle phase, respectively. Gas phase washout ratios of high molecular weight PAHs were greater than the lower molecular weight PAHs.

Research highlights
► Wet deposition and ambient air concentrations of polyaromatic hydrocarbons (PAHs) were collected at an urban site.
► Gas and particle phase concentrations in air and rainwater were determined.
► Coal combustion was the dominant source for air and rainwater levels in winter.
► Higher molecular weight PAHs had greater washout ratios than the lower ones.