Particulate Matter (PM2.5) and Mould Characteristics in Selected Classrooms Located in Waikato, New Zealand: Preliminary Results

Abstract

Small airborne particulate contaminants such as mould spores can harm human health by causing or exacerbating respiratory illnesses. Such particulates tend to be microscopic; however, in the case of moulds, contamination can be associated with visible colonial growth on surfaces and musty odours detectable by occupants of the room. Shared spaces, such as offices and classrooms, represent areas of higher risk due to the larger numbers of people being exposed to airborne particulates. To better appreciate the health risks associated with airborne particulates, it is therefore advantageous to assess the levels of breathable particulates in a room and compare them with the proportion of particulates represented by mould spores. An air image sensor machine was used to collect PM2.5 particulate levels for three urban-campus classrooms and three semi-urban-campus classrooms during different wintertime (August) days in New Zealand. For each room, a settle-plate method was also used to compare background mould levels at breathing height for seated occupants. Three of the classrooms had been recently built or renovated with an adequate ventilation system installed, while the remaining three classrooms were not upgraded and had no evidence of a ventilation system. The results indicated that the classrooms in the new building, located at the semi-urban campus, tended to have lower levels of particulate matter PM2.5 compared with the urban classrooms, which had not been upgraded. However, the semi-urban classrooms tended to have higher mould counts than the urban spaces. Moreover, the building envelope for both new and old classrooms tended to be porous, with indoor PM2.5 readings increasing in step with outdoor PM2.5 readings. This study will assist in identifying new approaches to reduce the risk of particulate-related respiratory issues associated with urban teaching spaces, particularly those buildings requiring more sustainable technologies to purify the air and improve the indoor air quality (IAQ).