Metrics on Perception, Concentration, and Characterization of Indoor Air Quality in a University Library

A longitudinal study was conducted to establish metrics on perception, concentration and characterization of indoor air quality (IAQ) at a university library building. A questionnaire was applied to library staff in 2016 and 2017 to measure perceived indoor air quality (PIAQ) and perceived respiratory health impacts (PRHI). Measurements of PM2.5-10 and PM2.5 concentration levels were made in 2017 and 2019, respectively. Characterization through morphology and elemental composition of particulate matter (PM) samples were obtained through scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). PIAQ metrics indicated eye and throat irritation, the presence of PM and biological compounds as determinants of IAQ. The library is perceived as a sick building and the indoor air is perceived as polluted. PRHI metrics indicated that respondents consider they have good respiratory health. Average PM2.5-24h was 3.67 μg.m-3 (95% CI: 1.58, 6.87), values well below international health-based recommendations. SEM-EDS analysis indicates that biogenic aerosols and mineral dust particles were dominant in 2017 and 2019 samples and that there is an influence of indoor and outdoor sources. PM was influenced by furniture, specific library activities and outside air delivered by the ventilation system, as well as through open windows. It is recommended that future studies consider other pollutants like formaldehyde and ozone.