Polychlorinated naphthalenes in urban air

Air samples were collected at an urban site (Chicago,IL) and a semi-urban location (Downsview, Ontario) in February and March 1995 to measure atmospheric concentrations and particle/gas partitioning of polychlorinated naphthalenes (PCN). PCNs were quantified by gas chromatography-negative-ion mass spectrometry (GC-NIMS) against Halowax 1014, a commercial mixture of PCN compounds. GC-flame ionization responses were used to assign mass percent contributions to congeners in Halowax 1014. The reliability of this method was checked using pure compounds and was within +/-20% of the true value for 5 out of 6 congeners tested. Mean atmospheric concentrations (Sigma PCN) at the urban and semi-urban site were 68 pg m(-3) (n=14) and 17 pg m(-3) (n=2), respectively. Several bioaccumulating PCNs which have ''dioxin-like'' toxicity similar to coplanar PCBs were quantified. The tetrachlorodibenzodioxin (TCDD) toxicity contribution of one of these PCNs in Chicago air was estimated to outweigh the contributions of some of the coplanar PCBs. The fraction of PCNs on particles exhibited a stepwise increase with homolog group. A need for relevant physicochemical data for this group of compounds was identified. (C) 1997 Elsevier Science Ltd.