An Evaluation of the Impact of Flooring Types and Ventilation Conditions on Exposures to Fine and Coarse Particles within the Residential Micro-Environment using CONTAM

Typical resuspension activities within the home, such as walking have been estimated to contribute up to 25 % of exposures to PM10. Chamber studies have also shown that for moderate walking intensities, for multiple participants, flooring type can impact the rate at which particles are re-entrained into the air column. The impact of flooring types on exposures resulting from the resuspension of fine and coarse particles while walking within the home was investigated using CONTAM. CONTAM is the National Institute of Standards and Technology's (NIST) mass transport and ventilation analysis software. First CONTAM's resuspension and deposition module was validated with a field study. The adjusted R-squared values comparing the predicted and measured concentrations of fine and coarse particles within an occupied home ranged from 89 -- 97 %.;CONTAM was next used to assess the influence of flooring types and ventilation conditions on average daily (24 hour) PM2.5 (fine PM) and PM 10 - 2.5 (coarse PM) exposure concentrations. Flooring type was determined to have significantly impact on average daily exposures to both fine and coarse particles (alpha = 0.05, p < 0.05, N = 490) with cut pile carpeting resulting in the highest average daily exposures. The median contribution of resuspension to average daily coarse PM exposures, within the residential environment for cut pile carpeting ranged from 13 -- 28 mug/m3. The corresponding figures for hardwood flooring were 0.67 -- 1.4 mug/m 3. For fine particles the median contribution of resuspended particles to average daily exposures for cut pile carpeting ranged from 0.82 -- 1.8 mug/m3 respectively. These results were associated with floor loadings ranging from 0.6 -- 1.3 g/m2 (particles with diameter < 45mum).;Increasing air change rates was observed to have a significant impact on average daily exposures to fine PM but no significant impact was observed for coarse PM.