Indoor air quality in typical temperate zone Australian dwellings

We report the results of a comprehensive study of indoor air quality in typical temperate zone Australian dwellings. Forty dwellings located over an 800 km2 area in the south-east of Melbourne with a range of ages, materials and structures representative of Australian dwellings were selected. A range of indoor air quality pollutants were sampled both inside and outside for one week each in Winter/Spring 2008 and Summer/Autumn 2009. Information was collected on house characteristics, the surrounding areas and occupant activities during the sampling. Weekly indoor averaged CO2 (536 ± 121 ppm), CO (0.3 ± 0.2 ppm), PM2.5 (8.4 ± 4.0 μg m−3), temperatures (21.2 ± 2.0 °C), water vapour mixing ratios (7.9 ± 1.3 g kg−1), benzene (1.3 ± 1.1 μg m−3), toluene (8.8 ± 7.9 μg m−3) and xylenes (6.2 ± 6.7 μg m−3) varied from 1.1 to approximately three times higher compared to the equivalent outdoors concentrations. Formaldehyde (12.2 ± 4.7 ppb), other carbonyls (7.9 ± 2.6 ppb) and total volatile organic compounds (181.1 ± 89.5 μg m−3) had indoor concentrations of factors between eight and 12 times higher compared to outdoor concentrations. Weekly averaged indoor ozone (0.7 ± 0.7 ppb), NO2 (8.4 ± 3.9 ppb) and PM10 (20.4 ± 8.1 μg m−3) were significantly lower than outdoors. Correlations and factor analysis showed the major influences on this indoor air quality were (a) dwelling age, whereby dwellings constructed in recent decades compared to older buildings were found to have increased concentrations of the highly elevated species formaldehyde, other carbonyls and total volatile organic compounds, and (b) combustion and cooking activities that increased the concentrations of multiple species including CO, CO2, NO2, H2O and particles. The indoor pollutant concentrations from this study were in general comparable with or lower than other Australian or overseas studies. ► Concentrations of common indoor pollutants measured in 40 Australian dwellings. ► Pollutants include CO2, NO2, CO, O3, particulates, formaldehyde and other carbonyls. ► Dwelling age, combustion and cooking activities found to have influence on air quality. ► Results are comparable to or lower than other Australian and overseas studies.