LONG-TERM HIGH-VOLUME AND LOW-VOLUME AIR SAMPLING OF POLYCHLORINATED DIBENZO-PARA-DIOXINS AND DIBENZOFURANS AND POLYCYCLIC AROMATIC-HYDROCARBONS ALONG A TRANSECT FROM URBAN TO REMOTE AREAS ON THE SWEDISH BALTIC COAST

Air samples were collected along a transect from the city of Stockholm urban area to the open coastal area of the Baltic Sea. Samples for polycyclic aromatic hydrocarbon (PAH) and polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) analysis were collected for 135 days (mean 860 m3) and for 5-64 days (6500-5400 m3), respectively. The concentrations were found to decrease with increasing distance from Stockholm with intervals of total concentrations of 1.4-0.2 pg/m3 (24-3 fg of toxic equiv/m3) for the PCDD/Fs and 11-2.5 ng/m3 for the PAHs. The lower concentrations were established as Scandinavian background air levels. Atmospheric transport time was found to govern aerosol adsorption of PAHs in the vapor phase, and the low temperature (-4-degrees-C) resulted in very high aerosol association for all PAHs. The estimated dry fluxes of PAHs and PCDD/Fs were 41 ng/cm2.year and 3.2 pg/m2.year, respectively, and the wet fluxes were 9.6 ng/cm2.year and 0.56 pg/cm2.year, respectively. Multivariate statistical analysis (SIMCA) indicated a spatial distribution, depending on the isomer and relative compound distribution, in accordance with distance from Stockholm for PCDD/Fs and PAHs. The air samples were statistically compared with settling and suspended particulate matter to establish the atmospheric input of PCDD/Fs and PAHs to the aquatic environment. Only for PCDD/Fs did the air samples show significant similarity in composition to the water samples.