Optimizing portable air cleaner performance testing protocols: A study on test room size, data interval, and practical CADR

The growing concerns about indoor air quality and airborne disease transmission have led to significant advancements in portable air cleaners (PACs), with many high-capacity units now designed for larger, non-residential spaces. However, most current testing standards remain outdated, primarily focusing on low-capacity, residential PACs and assuming idealized, well-mixed conditions. Key parameters such as test room size, measurement duration, and the distinction between theoretical and practical performance remain insufficiently studied. This study aims to bridge this gap by developing a practical CADR (CADR_pr) testing protocol and investigating how test room size and data point density affect CADR_pr and theoretical CADR (CADR_th). Both CADR_pr and CADR_th are experimentally measured parameters: CADR_th is measured under standard ANSI/AHAM AC-1 conditions with continuous air mixing, while CADR_pr is measured under relatively realistic conditions (mixing fans off) to represent typical room operation. Three PACs with diverse capacities and airflow designs are evaluated in two test rooms: a standard 28.4 m³ (TR1) and a larger 202.0 m³ room (TR2). These include units with rated CADR_th within the ANSI/AHAM AC-1 design range and a high-capacity unit exceeding it. Results show that dense data points significantly improve CADR calculation stability and accuracy. When PACs are within standard design range capacities, CADR_th values remain consistent across rooms, with CADR_pr also closely aligning. However, TR1 underestimates CADR_th by 28–55% for the high-capacity PAC, and CADR_pr falls 3–16% below theoretical values, depending on particle size. This study highlights the need to revise testing standards to better accommodate modern PAC capacities and real-world usage conditions.