AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Effect of Relative Humidity on Resuspension of Indoor Allergen Particles
PARICHEHR SALIMIFARD, Donghyun Rim, James Freihaut, The Pennsylvania State University
Abstract Number: 628 Working Group: Indoor Aerosols
Abstract Humidity of indoor air is one of the important factors in resuspension of particles from indoor surfaces, yet the effect of humidity is not clearly understood. Existing literature shows conflicting results, indicating that particle resuspension may increase or decrease depending on indoor humidity level. The objective of this study is to investigate the effect of humidity on resuspension of typical allergen containing particles. Experiments were conducted using four surrogate samples: quartz as a non-biological reference particle, and dust mite, dog fur and cat fur particles as indoor biological particles. The resuspension behavior of these particles, having the same size distribution as NIST reference dust, was investigated over a range of relative humidity levels from 10% to 80%. A small-scale resuspension chamber system was used to precisely control the relative humidity level and also simulate the mechanical and aerodynamic reservoir disturbances caused by occupant walking. The results showed that the particles in this experimental study can be divided into two groups: hydrophilic and hydrophobic particles. Resuspension rates of hydrophilic particles (quartz and dust mite) notably decrease as the relative humidity increases, while relative humidity variation has marginal effects on hydrophobic particles (cat fur and dog fur). The results suggest that the indoor humidity level is a significant contributing factor to the resuspension of the hydrophilic indoor dust particles. This finding implies that increasing indoor relative humidity, particularly in winter season, could be used as a method for reducing the resuspension of hydrophilic dust mite particles.