Black Carbon Concentrations Inside And Outside Occupied Residences

Black carbon (BC, soot, elemental carbon) is a component of airborne particulate matter, which has been linked with negative effects on respiratory and cardiovascular systems. BC is considered an indicator of combustion related component of particulate matter, which can be emitted from both outdoor and indoor sources. Pollution control measures focus mainly on outdoor concentrations, whereas control of indoor levels seem to be neglected despite the fact that we spend on average 90% of our time in indoor environments. The aim of this study was to assess the differences in BC concentrations inside and outside occupied residences during weeklong real time measurements in ten residences. BC concentrations were measured simultaneously indoors and outside of ten occupied residences using two microAeth (R) AE51 (AethLabs, USA) instruments. Continues measurements inside and outside lasted at least seven consecutive days in each residence. Comparisons of BC concentrations were conducted for the times when occupants were present at home and when there was no one in the residence. Average concentrations of BC during occupancy time were comparable between indoors and outdoors. However, a significant contribution of indoor sources to measured BC was observed. High concentrations of BC indoors were due to cooking and candle burning. Concentrations of BC during non-occupancy time were higher outdoors than indoors as expected, as there were no indoor activities which may have contributed to observed levels indoors. Obtained results indicate that in order to minimize exposure of occupants to BC concentrations, efficient control measures of indoor emissions might be as important as prevention of outdoor pollution infiltration to indoor environments.