Indoor Organic Aerosol Formation Near Building Occupants Using Computational Fluid Dynamics

SUWHAN YEE, Donghyun Rim, Pennsylvania State University

     Abstract Number: 613
     Working Group: Indoor Aerosols

Abstract
Several studies have developed chemical reaction models for secondary organic aerosol formation. The volatility basis set model is one of the methods that estimate the amount of aerosol formed from the total organic material. However, only a few studies focused on the spatial gradient of secondary organic aerosols near indoor occupants, as the volatility basis model assumes a well-mixed model. This study aims to investigate indoor aerosol formation due to indoor temperature gradients near humans and determine the effects of cooling, heating, and ventilation on indoor aerosol concentration. Computational fluid dynamics (CFD) simulation combined with two-dimensional volatility basis set (2D-VBS) model is used to demonstrate indoor aerosol formation from organic materials from outdoors. The 2D-VBS model used six different volatility bins for the outdoor organic materials. The indoor temperature gradient is calculated using CFD simulation, and the aerosol mass fraction is calculated for each volatility bin to predict the mass of aerosol formed indoors. Ventilation strategies are evaluated using the room average value of aerosol mass concentration and the concentration near the breathing zone. The simulation results show that the organic aerosol's mass concentration can vary due to different ventilation conditions. Especially the aerosol concentration tends to be lower with lower air exchange rates. Also, the aerosol concentrations near the breathing zone varied due to the occupant's position with respect to the air supply inlet. The study results indicate that the indoor organic particle concentration notably varies with cooling and heating conditions.