Mutagenicity of Bulk, Aqueous and Organic Partitions of Air Particulate Matter in Differentially Ventilated Wards in a Public Urban Hospital

The hospital environment requires indoor air quality conducive to the recovery of patients with poor health. Low indoor air quality is associated with an increased incidence of respiratory tract diseases and the development of cancer. This study investigated the mutagenicity of air particulate matter soluble in bulk, aqueous, and organic partitions collected from naturally and mechanically ventilated wards in the hospital environment through the Ames test and the mutagenicity testing with the D7 strain of Saccharomyces cerevisae. Bulk, aqueous, and organic fractions of air particulate matter at maximum (100% concentration), 10% concentration, and 1% were found to be mutagenic with both the Ames test (p < 0.05) and mutagenicity testing with D7 strain of S. cerevisae (p < 0.05). The Ames test suggested slight dominance of the aqueous phase-soluble mutagens in naturally ventilated wards (p < 0.05), and a more balanced mix of aqueous and organic phase mutagens in mechanically ventilated wards. Mutagenicity testing with the D7 strain of S. cerevisae showed no significant differences between the naturally and mechanically ventilated wards (p > 0.05), but showed the relative dominance of the organic phase-soluble mutagens over the other fractions (p < 0.05). Few other studies have compared naturally and mechanically ventilated wards through the lens of potential effect on the mutagenic activity of air particulate matter, but more understanding in this area is important in moving towards the development and implementation of policies to optimize ventilation systems for the health and safety of hospital staff and patients. Albeit coming from the study of concentrated air particulate matter samples, the mere presence of these mutagens in the air of the hospital highlights the importance of monitoring their quality and quantity such that they do not become concentrated enough to induce mutation-related etiologies of disease such as cancer.