Aerosol Sampling Biases in Personal Exposure Measurements. Charles E. Rodes, Tom M. Peters, Philip A. Lawless, Research Triangle Institute, Research Triangle Park, North Carolina 27709; and Lance Wallace, U. S. Environmental Protection Agency, Research Triangle Park, North Carolina, 27711
Biasing phenomena in aerosol sampling using Personal Exposure Monitors (PEMs) have been examined to assist in understanding the relationships between Personal and fixed-location Indoor sampling, and between Personal sampling and breathing zone concentrations. Physical situations being evaluated include (a) the role of carpeting in generating an aerosol "ground cloud" during walking, (b) the effect of the aerosol "ground cloud" on the vertical placement of the inlet on the body, and (c) the influence of the human "bluff body" on the capture of particles by the inlet as compared to a free-standing inlet. The aerodynamic size distributions of the particle released to the air from re-suspension during walking events are being investigated as a function of carpet type and age and the size distribution of dust on the carpet fibers. Personal sampling inlets located at the waist level are being compared with that at the lapel level to determine if significant concentration biases might be expected during extended sampling intervals. The sampled aerosol size distributions into PEMs located on a simulated body torso are being compared to those sampling in a free-standing location. Also being evaluated is the smaller bluff body presented by a simulated head and neck. Data will be presented on the measured aerosol size distributions produced as well as the expected influence on Personal and Indoor mass concentrations.
The U.S. Environmental Protection Agency through its Office of Research and Development funded and collaborated in the Research described here under cooperative agreement No. Cr 821902-01-0 to Research Triangle Institute. It has not been subjected to Agency review and therefore does not necessarily reflect the views of the Agency, and no official endorsement should be inferred.