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Published on: July 12, 2024
Infant and Adult Inhalation Exposure to Resuspended Biological Particulate Matter
Tianren Wu1,2, Martin Täubel3, Rauno Holopainen4
1Lyles School of Civil Engineering, Purdue University , 550 Stadium Mall Drive, West Lafayette, Indiana 47907, United States.
Abstract:
Human-induced resuspension of floor dust is a dynamic process that can serve as a major indoor source of biological particulate matter (bioPM). Inhalation exposure to the microbial and allergenic content of indoor dust is associated with adverse and protective health effects. This study evaluates infant and adult inhalation exposures and respiratory tract deposited dose rates of resuspended bioPM from carpets. Chamber experiments were conducted with a robotic crawling infant and an adult performing a walking sequence. Breathing zone (BZ) size distributions of resuspended fluorescent biological aerosol particles (FBAPs), a bioPM proxy, were monitored in real-time. FBAP exposures were highly transient during periods of locomotion. Both crawling and walking delivered a significant number of resuspended FBAPs to the BZ, with concentrations ranging from 0.5 to 2 cm-3 (mass range: ∼50 to 600 μg/m3). Infants and adults are primarily exposed to a unimodal FBAP size distribution between 2 and 6 μm, with infants receiving greater exposures to super-10 μm FBAPs. In just 1 min of crawling or walking, 103-104 resuspended FBAPs can deposit in the respiratory tract, with an infant receiving much of their respiratory tract deposited dose in their lower airways. Per kg body mass, an infant will receive a nearly four times greater respiratory tract deposited dose of resuspended FBAPs compared to an adult.
Insights
Human-induced dust resuspension releases biological particulate matter (bioPM). Infants receive significantly higher respiratory tract deposited doses of bioPM compared to adults, especially in lower airways.
Area of Science:
- Environmental Health
- Indoor Air Quality
- Toxicology
Background:
- Human activities, such as walking and crawling, dynamically resuspend indoor floor dust.
- Indoor dust contains biological particulate matter (bioPM) with microbial and allergenic components, linked to various health effects.
- Understanding bioPM exposure is crucial for assessing indoor health risks.
Purpose of the Study:
- To quantify infant and adult inhalation exposures to resuspended bioPM from carpets.
- To determine respiratory tract deposited dose rates of bioPM for different age groups.
- To compare exposure levels between infants and adults during locomotion.
Main Methods:
- Utilized chamber experiments with a robotic crawling infant and an adult performing walking sequences.
- Monitored real-time breathing zone (BZ) size distributions of fluorescent biological aerosol particles (FBAPs) as a bioPM proxy.
- Analyzed FBAP concentrations and size distributions during locomotion.
Main Results:
- Resuspension events were transient, delivering significant FBAPs to the BZ (0.5–2 cm⁻³).
- Both crawling and walking exposed individuals to FBAPs primarily between 2–6 μm.
- Infants received higher exposures to super-10 μm FBAPs and greater deposition in lower airways.
Conclusions:
- Locomotion significantly resuspends bioPM, leading to transient inhalation exposures.
- Infants experience a substantially higher respiratory tract deposited dose of bioPM per kg body mass compared to adults.
- Findings highlight the critical need to consider age-specific exposures to indoor bioPM.
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