Resuspension Behavior of Settled Dust Particles in the Infant-Occupied Indoor Environment

BRIAN MAGNUSON, Chunxu Huang, Satya Patra, Brandon E. Boor, Purdue University

     Abstract Number: 309
     Working Group: Indoor Aerosols

Abstract
During key motor development stages between 6 and 18 months of age, infants frequently disturb settled indoor dust on flooring surfaces through crawling, as their hands and limbs repeatedly contact the floor. These activities can lead to the inhalation of resuspended dust particles, increasing exposure to harmful contaminants commonly present in household dust, including per- and polyfluoroalkyl substances (PFAS), heavy metals, microplastics, flame retardants, plasticizers, allergens, and microorganisms. To better inform inhalation exposure estimates, it is critical to characterize the size-dependent transport behavior of dust particles during crawling. Resuspension experiments were conducted in the Inert Controlled Environmental Chamber (ICEC), which maintained conditions representative of infant-occupied indoor environments while supplying filtered air to isolate resuspended particles. Surface contact impulses simulating infant locomotion during crawling and play were generated using a robotic platform. Resuspended particles were characterized by aerodynamic diameter, optical diameter, and fluorescence using an aerodynamic particle sizer (APS), optical particle sizer (OPS), and wideband integrated bioaerosol sensor (WIBS), respectively. Size-resolved dust resuspension fractions were calculated using a single-zone material balance model for each crawling event. These experiments aim to improve our understanding of particle resuspension dynamics and their implications for infant inhalation exposure during critical developmental stages.