title: Pyrethroids in indoor air during application of various mosquito repellents: Occurrence, dissipation and potential exposure risk.
abstract: Commercial mosquito repellents (MRs) are generally applied as mosquito coils, electric vaporizers (liquid and solid) or aerosol spray, with pyrethroids often being the active ingredients. Four types of MRs were applied individually in a 13-m(2) bedroom to study the occurrence, dissipation and risk of pyrethroids in indoor environments. Total air concentrations (in gas and particle phases) of allethrin, cypermethrin, dimefluthrin and tetramethrin during MR applications were three to six orders of magnitude higher than indoor levels before the applications, and allethrin emitted from a vaporizing mat reached the highest concentration measured during the current study (18,600 ± 4980 ng m(-3)). The fate of airborne pyrethroids was different when the four MRs were applied. Particle-associated allethrin accounted for 95% of its total concentration from the aerosol spray, and was significantly higher than the vaporizing mat (67%), suggesting that the released phase of MRs and size distribution of pyrethroid-carrying particles played important roles in the gas-particle partitioning process. In addition, air exchange through open windows more effectively reduced the levels of indoor pyrethroids than ventilation using an air conditioner. The inhalation risk quotients (RQ) for allethrin derived from application of the vaporizing mat ranged from 1.04 ± 0.40 to 1.98 ± 0.75 for different age-subgroups of the population, suggesting potential exposure risk. Special attention should be given concerning indoor exposure of pyrethroids to these vulnerable groups.
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
authors.forename: Huizhen
authors.initials: H
authors.lastname: Li
authors.affiliation: Center for Fisheries, Aquaculture and Aquatic Sciences and Department of Zoology, 171 Life Science II, Southern Illinois University, Carbondale, IL 62901, United States.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lydy
authors.affiliation: State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China. Electronic address: youjing@gig.ac.cn.
authors.forename: Jing
authors.initials: J
authors.lastname: You
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D000818:Animals; D002648:Child; D002675:Child, Preschool; D009033:Culicidae; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007302:Insect Repellents / Q000008:administration & dosage* / Q000145:classification; D008297:Male; D008875:Middle Aged; D011722:Pyrethrins / Q000032:analysis*; D018570:Risk Assessment; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D007302:Insect Repellents; D011722:Pyrethrins
keywords: Exposure risk; Indoor air; Mosquito repellents; Pyrethroids