Occurrence of particle-associated polycyclic aromatic compounds in ambientair of the city of Munich

Concentrations of polycyclic aromatic hydrocarbons (PAH) and oxidised PAH ( oxy-FAH) from outdoor air were determined. Size-fractionated aerosol sample s were collected in the city of Munich (Germany). Twenty-four hour samples with six- and nine-stage Berner-type low-pressure impactors were collected between 1996 and 1998. Fluoranthene, pyrene, chrysene, benzo[b]fluoranthene , benzo[k]fluoranthene, benzo[a]pyrene and benzo[ghi]perylene were quantifi ed by HPLC with fluorescence detection. The averaged sum of these PAH reach ed 1.24 ng m(-3) (range: 0.68-1.85 ng m (-3)) at the inner city site which was not directly influenced by any road nearby, whereas samples from two si tes close to busy roads exhibited average PAH concentrations equal to 5.61 ng m(-3) (range: 3.65-6.65 ng m(-3)) and 5.74 ng m(-3) (range: 1.67-15.13 n g m(-3)). The PAH concentration observed at the northern outskirts of Munic h ranged from 0.15 to 9.45 ng m(-3) (average, 2.4 ng m(-3)). Different dist ributions of the PAH in the investigated particle size fractions were obser ved. Close to the road (at about 1 m off), about 40% of the PAH were found in the particle fraction with diameters of 0.06-0.13 mum Similar distributi ons were observed at the second sampling site located close to a road when winds blew directly from this road. When winds blew from other directions, higher percents of PAH were present on larger particles. A bigger accumulat ion of PAH on particles ranging from 0.26 to 0.9 mum was also observed at t he outskirts. Since the lung dose of particle-associated compounds is influ enced by the distribution of the compounds within the particle size range, the observed differences in the distribution of PAH have implications on hu man exposure. (C) 2001 Elsevier Science Ltd. All rights reserved.