title: Evaluation of particle resuspension in young children's breathing zone using stationary and robotic (PIPER) aerosol samplers.
abstract: Development of asthma in young children may be associated with high exposure to particulate matter (PM). However, typical stationary samplers may not represent the personal exposure of children ages 3 and younger since they may not detect particles resuspended from the floor as children play, thus reducing our ability to correlate exposure and disease etiology. To address this, an autonomous robot, the Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler, was developed to simulate the movements of children as they play on the floor. PIPER and a stationary sampler took simultaneous measurements of particle number concentration in six size channels using an optical particle counter and inhalable PM on filters in 65 homes in New Jersey, USA. To study particle resuspension, for each sampler we calculated the ratio of particle concentration measured while PIPER was moving to the average concentration of particles measured during a reference period when PIPER remained still. For all investigated particle sizes, higher particle resuspension was observed by PIPER compared to the stationary sampler. In 71% of carpeted homes a more significant (at the α = 0.05 level) resuspension of particles larger than 2.5 μm was observed by PIPER compared to the stationary sampler. Typically, particles larger than 2.5 μm were resuspended more efficiently than smaller particles, over both carpeted and bare floors. Additionally, in carpeted homes estimations of PM10mass from the particle number concentrations measured on PIPER while it was moving were on average a factor of 1.54 higher compared to reference period when PIPER was not moving. For comparison, the stationary sampler measured an increase of PM2.5mass by a factor of only 1.08 when PIPER was moving compared to a reference period. This demonstrates that PIPER is able to resuspend particles through movement, and provide a better characterization of the resuspended particles than stationary samplers. Accurate measurement of resuspended PM will improve estimates of children's total PM exposure.
authors.affiliation: Department of Environmental Sciences, Rutgers University, 14 College Fa rm Rd., New Brunswick, NJ 08901.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Sagona
authors.affiliation: Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901 ; Environmental and Occupational Health Sciences Institute, Rutgers University, 170 Frelinghuysen Rd., Piscataway, NJ 08854.
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Shalat
authors.affiliation: Department of Environmental Sciences, Rutgers University, 14 College Fa rm Rd., New Brunswick, NJ 08901.
authors.forename: Zuocheng
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Pediatrics, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901.
authors.forename: Maya
authors.initials: M
authors.lastname: Ramagopal
authors.affiliation: Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Black
authors.affiliation: Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901.
authors.forename: Marta
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: Department of Environmental Sciences, Rutgers University, 14 College Fa rm Rd., New Brunswick, NJ 08901 ; Environmental and Occupational Health Sciences Institute, Rutgers University, 170 Frelinghuysen Rd., Piscataway, NJ 08854.
authors.forename: Gediminas
authors.initials: G
authors.lastname: Mainelis
keywords: PM size fractions; Pretoddler Inhalable Particulate Environmental Robotic sampler; children's exposures to PM; floor type; resuspension; robotic sampling platform