This study presents an integrated indoor air quality index (IAQI) algorithm aimed at enhancing the efficiency of indoor air quality management in diverse indoor environments. The proposed IAQI accounts for the combined effects of multiple pollutants, offering a more comprehensive approach than traditional concentrationbased methods. Findings from four exposure scenarios and probabilistic health risk assessments indicate that the IAQI can be tailored to reflect occupant characteristics and space usage, thereby providing improved protection for sensitive populations, such as newborns. The application of occupant-specific criteria led to reductions in pollutant concentrations and associated health risks compared to conventional standards. Furthermore, the IAQI incorporates correction factors and weighted adjustments, facilitating robust risk assessments in complex multi-pollutant contexts. By addressing the limitations of single-pollutant management, this approach supports the development of more effective strategies for indoor air quality control. The proposed algorithm holds significant potential for practical applications in indoor air quality management and policymaking. Future research should focus on validating its effectiveness across a wider range of indoor environments.

A study was conducted to evaluate the proper particle cleaned air changes per hour (PCH) in apartment buildings and school classrooms. The concept of PCH was newly introduced. The PCH can be expressed as the clean air delivery rate (CADR) per space volume. The PCH includes the filtering effect with air changes per hour (ACH). A method for calculating the proper PCH was theoretically proposed and experimentally verified. The proper PCH to effectively control ultrafine particles in apartments and school classrooms was found to be 4.0/h and 4.2/h, respectively. In general, air cleaners and mechanical ventilation devices are often used together in apartments and school classrooms. In such cases, it is important to consider the proper PCH of each device and control it for energy-efficient operation. In addition, in times of concern for infection such as COVID-19, it will be necessary to operate the PCH at 6.0/h or more to minimize the probability of infection.

Ventilation devices and room air cleaners can be used to remove indoor contaminants from indoor air. Generally, room air cleaners are rated according to clean air delivery rate (CADR). However, a similar metric for ventilation has not been used to be compared with CADR of room air cleaner. The CADRs and cost-effectiveness metrics (CADR/kw) of ventilation devices and room air cleaners were newly defined and theoretically compared for a child care center. The results indicate that the CADRs of room air cleaner were greater than that of ventilation. A higher collection efficiency for the particles guaranteed a higher CADR for ventilation. Ventilation filter had a performance that exceeds MERV11 should be used to effectively control the indoor particle concentration. The stand alone type air cleaner was found to have the best performance in the cost-effectiveness. The reason for this is that the effective air cleaning ratio of the stand alone type air cleaner is higher than that of the others and the power consumption of the stand alone type air cleaner is lowest.

We performed numerical analyses on the optimal discharge angle of a 4-way cassette air conditioner, which is mounted on the ceiling of the classroom, by using thermal comfort and ventilation indices. We analyzed the effective draft temperature, the local mean age and the local mean residual life time with respect to the variation of the air discharge angle of the air conditioner in all occupied zone. Air diffusion performance index, local supply effectiveness and local exhaust effectiveness were used to investigate the optimal value of air discharge angle. From the results, we found out that the optimal discharge angle of the air conditioner is about 40 degrees in the present model.