Variability in Indoor Dust Surface Concentrations and Size Distributions among Urban and Suburban Homes in the U.S.
SATYA PATRA, Brian Magnuson, Iane Gomes, Laura Ajala, Paige Thompson, Orit Herzberg, Meghan Kalvey, Emily Halpern, Alexander Laskin, Laura Claxton, Karen Adolph, Brandon E. Boor,
Purdue University Abstract Number: 258
Working Group: Indoor Aerosols
AbstractInfants can be exposed to environmental toxicants in indoor dust via ingestion and inhalation. Dust ingestion can occur following particle contact transfer between indoor surfaces and mouthed objects and dust inhalation can occur following infant movement-induced particle resuspension. Both contact transfer and resuspension are dependent on the physical characteristics of indoor dust. The aim of this study is to investigate how home and demographic factors influence indoor dust surface concentrations and size distributions to better predict early-childhood exposure to dust-bound toxicants. Indoor dust was collected from urban homes in New York, NY and suburban and rural homes in West Lafayette, IN using a standardized vacuum-based collection method. Home video tours and parent-report questionnaires were used to collect information on home and demographic factors that may influence the presence and amount of indoor dust. Indoor dust samples were sieved, weighed, and analyzed via a laser diffraction particle sizer. Suburban and rural homes had higher indoor dust surface mass concentrations (mean: 3.9 (±0.9) g m
-2) compared to urban homes (mean: 2.7 (±0.9) g m
-2). Entryways exhibited the highest surface concentrations across both locations (mean: 8.7 (±1.7) g m
-2), followed by living/family rooms (mean: 3.2 (±0.8) g m
-2) and bedrooms (mean: 2.6 (±1.0) g m
-2). Furthermore, the type of indoor flooring influenced dust surface concentrations, with the highest levels found on area rugs (mean: 5.2 (±1.7) g m
-2), followed by carpets (mean: 4.2 (±0.8) g m
-2), and considerably lower surface concentrations on hardwood flooring (mean: 0.3 (±0.1) g m
-2). Indoor dust surface volume size distributions spanned from approximately 1 to 1,000 µm and commonly featured two prominent modes: one between 10 and 30 µm and another between 80 and 120 µm. The implications of the variability in indoor dust surface concentrations and size distributions on infant exposures will be discussed.