Chlordanes in the Indoor and Outdoor Air of Three U.S. Cities.

Indoor and outdoor concentrations of six chlordane components (trans-chlordane, cis-chlordane, trans-nonachlor, cisnonachlor, oxychlordane, and MC5) were measured at 157 residences, all of which were inhabited by nonsmoking individuals, in three urban areas during June 1999-May 2000. The analyses were conducted on a subset of 48 h integrated samples collected in Los Angeles County, CA, Houston, TX, and Elizabeth, NJ within the Relationship of Indoor, Outdoor, and Personal Air (RIOPA) study. Both particle-bound (PM2.5; quartz fiber filter) and vapor-phase (PUF sorbant) chlordane concentrations were separately measured by GC/El MS after solvent extraction. The outdoor (gas + particle) total chlordane (trans-chlordane + cis-chlordane + trans-nonachlor + cis-nonachlor) concentrations ranged from 0.036 to 4.27 ng m-3 in Los Angeles County, from 0.008 to 11.00 ng m-3 in Elizabeth, and from 0.062 to 1.77 ng m-3 in Houston. The corresponding indoor total chlordane concentrations ranged from 0.037 to 112.0 ng m-3 in Los Angeles County, from 0.260 to 31.80 ng m-3 in Elizabeth, and from 0.410 to 38.90 ng m-3 in Houston study homes. Geometric mean concentrations were higher in indoor air than outdoor air (1.98 vs 0.58 ng m-3 in CA; 1.30 vs 0.17 ng m-3 in NJ; 4.18 vs 0.28 ng m-3 in TX), which suggests there are significant indoor sources of chlordane species in a subset of homes in each of the three cities. Calculated source strengths relate to home age, with the highest apparent indoor source strengths occurring in unattached single-family homes built during the period from 1945 to 1959. Principle indoor sources of chlordanes likely include volatilization from residues of indoor application of chlordanes and infiltration from subsurface and foundation application of chlordane-containing termiticides during home construction. [ABSTRACT FROM AUTHOR]