Within- and between-home variability in indoor-air insecticide levels during pregnancy among an inner-city cohort from New York City

BACKGROUND: Residential insecticide use is widespread in the United States, but few data are available on the persistence and variability in levels in the indoor environment. OBJECTIVE: The study aim was to assess within- and between-home variability in indoor-air insecticides over the final 2 months of pregnancy among a cohort of African-American and Dominican women from New York City. METHODS: Women not employed outside the home were enrolled between February 2001 and May 2004 (n = 102); 9 insecticides and an adjuvant were measured in 48-hr personal air samples and 2 week integrated indoor air samples collected sequentially for 7.0 +/- 2.3 weeks (n = 337 air samples). RESULTS: Sixty-one percent of the women reported using pest control during the air samplings. Chlorpyrifos, diazinon, and propoxur were detected in 99-100% of personal and indoor samples (range, 0.4-641 ng/m(3)). Piperonyl butoxide (a pyrethroid adjuvant) was detected in 45.5-68.5% (0.2-608 ng/m(3)). There was little within-home variability and no significant difference in air concentrations within homes over time (p >= 0.2); between-home variability accounted for 88% of the variance in the indoor air levels of propoxur, 92% in chlorpyrifos, 94% in diazinon, and 62% in piperonyl butoxide (p < 0.001). Indoor and maternal personal air insecticide levels were highly correlated (r = 0.7-0.9, P < 0.001). Diazinon and chlorpyrifos levels declined 5-fold between 2001 and 2004 but were detected in all homes 1.5 and 2.5 years, respectively, after the U.S. Environmental Protection Agency ban on their residential use. CONCLUSION: Results showed that the insecticides were persistent in the home with little variability in air concentrations over the 2 months and contributed to chronic maternal inhalation exposures during pregnancy.