Indoor Air Quality Assessment in Heritage Adaptive Reuse: A Case Study of Cagayan de Oro City Museum

Abstract

This study addresses a critical research gap in assessing indoor air quality (IAQ) in adaptively reused heritage structures. IAQ assessment measured chemical and biological air pollution parameters in the century-old Cagayan Waterworks Tank, repurposed as the Cagayan de Oro City Museum. Using standardized air sampling methodologies, the proponent measured the Air Quality Index (AQI), the Index of Microbial Air Contamination (IMA), and bacterial pollution levels. Results revealed a dichotomy in pollution parameters: chemical pollutants showed favorable conditions, with an average AQI of 12 (categorized as "GOOD"), while biological parameters suggested concerning levels, with an average IMA of 51 (classified as “POOR”, since it falls at the lower boundary of the 51–75 range) and bacterial contamination at 728 CFU/m³ (indicating a "HIGH" degree of bacterial pollution). Statistical analysis, including Spearman's correlation tests, observed an exploratory positive monotonic trend between microbial contamination indices and bacterial pollution levels, suggesting an association with ventilation and HVAC system deficiencies in the adaptively reused heritage building. The findings provide preliminary evidence supporting targeted intervention strategies to reduce biological pollutants, including the implementation of indoor air quality (IAQ) monitoring systems, enhancements to sanitation protocols, HVAC system rehabilitation, and spatial reorganization. This research contributes valuable insights into sustainable heritage preservation by identifying the specific indoor air quality challenges in adaptively reused heritage structures.