The effects of portable air cleaner location on air quality in dental examination room by using computer fluid dynamic analysis

Abstract

Objective: The aim of this study was to investigate the air conditioner grille direction and the impact of portable air cleaner placement on air quality in dental treatment rooms using computational fluid dynamics (CFD). Research Methodology: This research utilized data from an actual dental treatment room at the Faculty of Dentistry, Chiang Mai University, to create a computational model. The study was divided into two main parts. The first part examined the effects of air conditioner grille directions, considering all six possible directions. The airflow patterns in the dental treatment room were analyzed accordingly. From the results of the first part, specific air conditioner grille directions were selected, resulting in suitable and unsuitable airflow patterns. These orientations were studied in combination with changes in the positions of the portable air cleaner, which had five possible positions within the dental treatment room. These positions included two at the rear, on the left and right sides of the dental chair, and three positions at the foot end of the dental chair, specifically, the center, left, and right positions. The airflow direction and aerosol distribution were analyzed using ANSYS Fluent software. Results: The study discovered that adjusting the direction of the air conditioner grille significantly influenced the airflow patterns in the dental treatment room. In adjusting the airflow direction of the air conditioner, certain directions resulted in unsuitable airflow patterns where air flowed past the patients before reaching the dentist. Conversely, some airflow directions of the air conditioner led to better airflow circulation, ensuring that air effectively passed through the dental treatment area before being expelled, creating a suitable and efficient airflow direction. In the second part of the study, two specific airflow directions, the straight central direction and the 45-degree downward direction, were selected based on the findings from the initial investigation. These directions were studied in conjunction with changes in the positions of the portable air cleaner. The study concluded that altering the position of the portable air cleaner significantly influenced its efficiency in removing particles within the dental treatment room. The optimal position for the portable air cleaner in a dental treatment room when the air conditioner directs the airflow straight or downward at a 45-degree angle is close to the treatment area and at the center towards the foot end of the dental chair, respectively. Conclusions: Good ventilation in the dental examination room begins with proper air circulation and the correct portable air cleaner placement. Installing the portable air cleaner in an appropriate position would significantly enhance the portable air cleaner's operation efficiency. Additionally, other factors such as room size, the positioning of air conditioning units, and air exhaust fans should also be considered to improve ventilation effectiveness and reduce particle dispersion during dental procedures.