Analysis of halogenated methoxybenzenes and hexachlorobenzene (HCB) in the picogram m−3 range in marine air

Summary Halogenated methoxybenzenes (halogenated anisoles) and hexachlorobenzene (HCB) have been analyzed in marine air samples from the lower troposphere of the East Atlantic Ocean, taken on the German, research vessel ‘Polarstern’ during two cruises in 1993 and 1994, and in air samples from the North Pacific Ocean (1995). The high-volume sampling method, sample preparation and analysis by HRGC-ECD and HRGC-MSD-SIM are described. The effectiveness of a new graphitized-carboncovered silica sorbent (ANGI-Sorb B) for the sampling of semi-volatiles is demonstrated. Eight congeners of the halogenated anisoles and HCB were detected in almost all marine air samples. The concentrations of the chloroanisoles, which show a distinct north-south interhemispherical gradient, were between 0.2 and 145 pg m⁻³; for the bromaanisoles concentrations were between 0.2 and 42 pg m⁻³. Only a weak inter-hemispheric gradient was observed for HCB at levels of 10–40 pg m⁻³. Levels of HCB were approximately 100 pg m⁻³ in continentally influenced air. Biogenic and indirect anthropogenic sources of the halogenated anisoles are discussed. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996