SAMPLING AND ANALYSIS OF POLYCYCLIC AROMATIC HYDROCARBONS IN URBAN AND RURAL ATMOSPHERES: SPATIAL AND GEOGRAPHICAL VARIATIONS OF CONCENTRATIONS

Abstract

Atmospheric sampling (gas and particles) of PAHs (naphthalene, acenaphthene, fluorene, anthracene, phenanthrene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, dibenz[a,h]anthracene, indeno[1,2,3-cd]pyrene, coronene) on XAD-2 resin (20 g) and glass fiber filters respectively, were performed in 2002 by using Digitel DA80 high-volume samplers equipped with a PM10 head. Samplings were performed in Strasbourg (east of France) and its vicinity (Schiltigheim and Erstein). Sites were chosen to be representative of urban (Strasbourg), suburban (Schiltigheim), and rural (Erstein) conditions. Field campaigns were undertaken simultaneously in urban, and suburban, urban and rural sites during spring and autumn during 4 h at a flow rate of 60 m³/h⁻¹ which gives a total of 240 m³ · h⁻¹ of air per sample. The period of sampling varied between 06:00 to 10:00, 11:00 to 15:00, 17:00 to 21:00 in order to evaluate a variation of concentration during automobile traffic between urban, suburban, and rural areas. Gas and particle samples were separately Soxhlet extracted for 12 h with a mixture of CH₂Cl₂/n-hexane (50:50 v/v), concentrated to about 1 mL with a rotary evaporator and finally dried under nitrogen. Dry extracts were dissolved in 1 mL of CH₃CN before analysis. Before use, traps were Soxhlet cleaned for 24 h with the same mixture as used for the extraction. Analysis of each extract was performed by reverse phase HPLC, and fluorescence detection and quantification was done with respect to triphenylene used as internal standard. Results shows that automobile traffic seems to be the main source of PAHs in urban areas whatever the period (autumn and spring) while in autumn other sources, especially coming from combustion, influence the atmospheric contamination by PAHs.

Keywords:

• polycyclic aromatic hydrocarbons
• rural air
• spatial variations of concentrations
• urban air

Acknowledgments

The authors thank the Région Alsace and the French Ministry of Environment (MEDD) for a DRIRE-Alsace Grant for their financial support. ASPA is also gratefully acknowledged for supplying DA-80 high-volume samplers.