Monthly measurements of indoor allergens and the influence of housing typein a northeastern US city

Background: We examined seasonal variation of dust-mile (Der f 1 and Der p 1), cat (Fel d 1), and cockroach (Bla g 1) allergens in Boston, while adjus ting for other covariates. Limited data are available on seasonal patterns of indoor allergen concentrations for different geographic regions in the U SA. Understanding within-home seasonal variation of allergens is important epidemiologically and clinically. Methods: From June 1995 to June 1996, dust samples were vacuumed monthly fr om the bed, bedroom floor; and kitchen of 20 homes. Indoor temperatures wer e measured monthly and used in calculating relative and absolute humidity. Monthly home characteristics questionnaires were completed by an adult resi dent of each home. Dust samples were assayed by enzyme-linked immunosorbent assays. Results: Der f I and Der p 1 in beds and floors peaked in the autumn months , Fel d 1 peaked in winter and spring, and Bla g 1 was highest in summer. D ust-mite allergen concentrations were 1.9-2.4 times higher in autumn than s pring, but the levels in beds were 19-31 times higher in houses than those in apartments. Although Fel d 1 levels in beds were 2.4 times higher in spr ing than summer, homes with cats had levels 224 times higher than those wit hout cats. Similarly, Bla g 1 levels in kitchens were 2.1 times higher in s ummer than winter, but apartments had, levels five times higher than those of houses. Conclusions: Sampling season is a source of within-home dust-mit e, fat, and cockroach allergen variation in-the northeastern USA. However, the influence of housing type and owning a cat far outweighed the seasonal Variation of these indoor allergens.