A methodology for predicting particle penetration factor through cracks of windows and doors for actual engineering application

Epidemiologic evidences have shown a strong relationship between exposure to outdoor particles and adverse impact on human health. A large amount of outdoor particles may penetrate into the indoor environments, where people spend about 90% of their life time. Therefore, predicting particle penetration into buildings could help to quantify the indoor exposure to particles with an outdoor origin and thus to develop effective strategies to remediate the exposure. However, there are few methodologies of particle penetration prediction for actual engineering application. In this paper, we present a methodology for predicting the particle penetration factor for real buildings by estimating the geometries of the cracks in the building envelopes according to the American Society of Heating, Refrigeration, Air-Conditioning Engineers (ASHRAE) Handbook. In addition, the effect of inertial impaction was considered. Furthermore, the effect of gravitational settling was neglected for vertical leakages. Two field measurements showed that the proposed methodology was effective in predicting the particle penetration factor for the test rooms. For particles in the range of 0.5–6 μm in diameter, the experimental data of penetration factors vary from 0.2 to 1, which match well with the predicted data. Generally speaking, this methodology can be used to aid the engineers or designers to calculate the particle penetration in actual engineering practices or designs. In addition, a sensitivity analysis was conducted to investigate the influencing factors.