Indoor air pollutants in occupational buildings in a sub-tropical climate: Comparison among ventilation types

Few studies have concurrently assessed both abiotic and biotic air pollutants in the built environment in sub-tropical areas. The investigation comprised a field study of air pollutants in eleven indoor environments in Sydney throughout one year, to elucidate Indoor/Outdoor ratios of carbon dioxide, carbon monoxide, total volatile organic compounds, nitric oxide, nitrogen dioxide, sulfur dioxide, total suspended particulate matter, suspended particles <10 μm in diameter (PM10) and particulate matter <2.5 μm (PM2.5). Further, a concurrent assessment of airborne fungi was conducted along with the other air pollutants to determine their diversity and abundance for urban Sydney and to establish baseline Indoor/Outdoor ratios of airborne fungi. Building ventilation types were identified as natural, mechanical and mixed-type ventilation, to assess whether building ventilation type has an impact on prevalence and concentrations of indoor air pollutants. We found that generally the indoor air quality of a typical Australian office building is relatively good. The ventilation type of the buildings did affect indoor air quality; however not to the extent that occupant health was at risk in any case. Low concentrations of airborne fungi were encountered in samples, across all buildings and months, with naturally ventilated buildings having higher concentrations. Buildings with high airborne fungal concentrations also supported higher diversity of fungal species. Few organisms of concern to public health were identified. Significant differences were observed when comparing the structure of airborne fungal communities across building types, with buildings with centralised mechanical (air conditioning) systems harbouring different communities to the other ventilation types.