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).