Effect of Indoor Air Ventilation on Particulate Pollutant Concentration Distribution, Including Nucleation, Coagulation and Surface Growth

Abstract

Typical furniture inside residential or office buildings is made from materials that emit terpenes. Terpenes react with ozone in the air, and produce secondary organic aerosols (SOA). During summer the concentration of SOAs may exceed by a factor of two to five times the concentration in outdoor air. The high concentration of SOA could adversely influence the human health. The air ventilation inside the room as well as the particles’ Brownian motion causes the particles to mix and coagulate. The coagulation of SOAs due to their collision leads to an increase in sizes in time. Coagulation, surface growth and nucleation of particles are the mechanisms which change the particle size and concentration distribution. The particle size distribution is important as large particles sediment rapidly and they are not a health threat for residents while fine and ultra fine particles stay suspended in the air and could enter the human respiratory system. A typical office room with furniture and a manikin was modeled in this study. The indoor airflow was simulated and was followed by the analysis of dispersion and coagulation of particles using the moment method. Two types of ventilation systems were modeled, and the results were compared discussed.