Showing papers by "Siming You published in 2015"

Experimental investigation and modelling of human-walking-induced particle resuspension

Abstract: Long-term exposure to airborne particulate matter (PM) indoors can cause adverse health effects to the occupants. Such exposure can be influenced by human-walking-induced particle resuspension (HWIPR). Several factors affecting HWIPR were investigated experimentally. The resuspension rates during walking were calculated based on the mass balance model, and the power law was applied to fit the resuspension rate data. The resuspension rate was further normalized for investigating the effects of various factors on HWIPR. It was found that the normalized resuspension rate of PM10 was about 2.5 times that of PM2.5 for both carpet and wood polyvinyl chloride (PVC). The normalized resuspension rate from carpet was about twice as much as the rates from wood PVC and four times that from vinyl. For both carpet and vinyl, the resuspension rates under the low relative humidity (RH) (41%) were three times that under the medium RH (63%) and 3.5 times that under the high RH (82%). The experimental results suggest that t...

A Risk Assessment Scheme of Infection Transmission Indoors Incorporating the Impact of Resuspension.

Abstract: A new risk assessment scheme was developed to quantify the impact of resuspension to infection transmission indoors. Airborne and surface pathogenic particle concentration models including the effect of two major resuspension scenarios (airflow-induced particle resuspension [AIPR] and walking-induced particle resuspension [WIPR]) were derived based on two-compartment mass balance models and validated against experimental data found in the literature. The inhalation exposure to pathogenic particles was estimated using the derived airborne concentration model, and subsequently incorporated into a dose-response model to assess the infection risk. Using the proposed risk assessment scheme, the influences of resuspension towards indoor infection transmission were examined by two hypothetical case studies. In the case of AIPR, the infection risk increased from 0 to 0.54 during 0–0.5 hours and from 0.54 to 0.57 during 0.5–4 hours. In the case of WIPR, the infection risk increased from 0 to 0.87 during 0–0.5 hours and from 0.87 to 1 during 0.5–4 hours. Sensitivity analysis was conducted based on the design-of-experiments method and showed that the factors that are related to the inspiratory rate of viable pathogens and pathogen virulence have the most significant effect on the infection probability under the occurrence of AIPR and WIPR. The risk assessment scheme could serve as an effective tool for the risk assessment of infection transmission indoors.