AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Resuspension Fraction Estimations from 20 Homes in Northern New York
Yuanyin Yin, Yan Ma, Lisa Bramwell, ANDREA R. FERRO, Clarkson University
Abstract Number: 313 Working Group: Indoor Aerosols
Abstract Indoor particulate matter (PM) concentration can be elevated by human activities such as dusting, vacuuming and walking. The resuspended particles can greatly increase human exposure to dust pollutants since people are indoors most of the time. However, most previous studies in this area have been conducted in the laboratory or in a single residence. The objectives of this study are 1) to estimate the house dust resuspension fractions (particle fraction resuspended from flooring per footstep) in real homes; 2) to compare the results with previous studies conducted in laboratories and residences; 3) to determine the difference of resuspension fractions for different flooring types. Walking activities were performed in the main living area of 20 homes in northern New York State. A 10-minute slow walking (68 steps per min.) and 10-minute fast walking (103 steps per min.) were each followed by a 50-minute decay period. Air particle concentrations were monitored semi-continuously both indoors and outdoors using a Grimm (Douglasville, GA) Model 1.108 optical particle counter with 6 seconds interval. Dry ice was emitted as a pulse release in the houses so the air exchange rate could be indicated by CO2 concentration. Floor loading samples were collected by a High Volume Small Surface Sampler (HVS3) for particles with aerodynamic diameters >5μm followed by a MOUDI$^(TM) (MSP, Shoreline, MN) for particles <5μm. The homes were kept unoccupied except the ten minute walking periods so no other human activities or other particle sources occurred in the houses. Hard floorings were found to have lower floor loadings (mass of particles per floor area) than carpeted floorings. The resuspension fractions were calculated using a two-compartment materials balance model for four size bins: 0.5-1.0μm, 1.0-3.0 μm, 3.0-5.0 μm, 5.0-10.0 μm. It was found that the resuspension fractions ranged widely from 10$^(-5) to 10$^(-1), with larger particles having larger resuspension fractions, which matches previous lab studies.