Temporal evolution of ultrafine particles and of alveolar deposited surface area from main indoor combustion and non-combustion sources in a model room.

Aerosol number size distributions, PM mass concentrations, alveolar deposited surface areas (ADSAs) and VOC concentrations were measured in a model room when aerosol was emitted by sources frequently encountered in indoor environments. Both combustion and non-combustion sources were considered. The most intense aerosol emission occurred when combustion sources were active (as high as 4.1×107particlescm-3 for two meat grilling sessions; the first with exhaust ventilation, the second without). An intense spike generation of nucleation particles occurred when appliances equipped with brush electric motors were operating (as high as 106particlescm-3 on switching on an electric drill). Average UFP increments over the background value were highest for electric appliances (5-12%) and lowest for combustion sources (as low as -24% for tobacco cigarette smoke). In contrast, average increments in ADSA were highest for combustion sources (as high as 3.2×103μm2cm-3 for meat grilling without exhaust ventilation) and lowest for electric appliances (20-90μm2cm-3). The health relevance of such particles is associated to their ability to penetrate cellular structures and elicit inflammatory effects mediated through oxidative stress in a way dependent on their surface area. The highest VOC concentrations were measured (PID probe) for cigarette smoke (8ppm) and spray air freshener (10ppm). The highest PM mass concentration (PM1) was measured for citronella candle burning (as high as 7.6mgm-3).