Impact of indoor ventilation efficiency on acetone inhalation exposure concentration and tissue dose in respiratory tract

A significant feature of the indoor environment is the heterogeneity of airflow and pollutant distributions,which are primarily dependent on ventilation systems.In the case of short-and high-concentration exposures to hazardous chemical pollutants,it may be necessary to precisely determine the concentration in the breathing zone or,more directly,the inhalation exposure concentration in the respiratory tract,rather than the representative room average concentration in an indoor environment,because of the non-uniformity of pollutant concentration distributions.In this study,we developed a computer-simulated person with a detailed respiratory system to predict inhalation exposure concentration and inhalation dose via transient breathing and reported a demonstrative numerical simulation for analyzing acetone concentration distributions in a simplified model room.Our numerical analysis revealed that the ventilation efficiency distribution in a room could change significantly by changing the design of the ventilation system,and that the inhalation exposure concentration estimated by a computer-simulated person could differ from the representative concentration,such as perfect-mixing or volume-averaged acetone concentration,by a factor of two or more.

Decreasing inhaled contaminant dose of a factory worker through a hybrid Emergency Ventilation System:Performance evaluation in worst-case scenario

Air pollution is detrimental to human health,causing several human illnesses.The industrial microenvironment generates high levels of indoor airborne pollutants,becoming a pervasive issue for workers.It is essential to im-prove the indoor air quality in this workplace by applying enhanced ventilation systems to minimize inhalation risk.Displacement ventilation is used in industrial buildings because of its stratified air distribution and low cost.However,in case of accidental pollutant release,an enhancement is needed to minimize inhalation exposure.This study proposes a hybrid emergency ventilation system using localized push-pull ventilation to improve the installed displacement ventilation system of a representative workshop.Computational fluid dynamics was ap-plied to calculate steady-state indoor air flow and volume-averaged pollutant concentration.System performance was evaluated in terms of source position;a computer simulated person was integrated to the building to confirm effectiveness against personal inhalation.Results showed marked improvement in performance when push-pull technique was used:room-averaged concentration diminished up to 91%while ventilation rate only increased 4%.Inhaled pollutant mitigation was achieved but performance dependence against leakage source and personal position was confirmed.