The effect of source type and source strength on inhaled mass of particulate matter during episodic indoor activities

A two-week campaign was performed in a naturally ventilated apartment to quantify indoor sources and to estimate the total inhaled mass of particulate matter (PM). DustTrak photometers were used to record PM2.5 concentrations continuously. Indoor activities were recorded in a detailed time–activity diary. The results showed that short episodic indoor sources influenced the indoor PM concentration for several hours and significantly affected daily average PM2.5 concentrations, indoor/outdoor ratios and indoor/outdoor correlation coefficients. Activities leading to increased PM concentrations occurred in 9% of the total time monitored, and accounted for 68% of the total PM concentration. Among the many indoor activities recorded, smoking and hair spraying were the strongest sources of fine aerosol. The outcomes of cooking episodes were the most variable in terms of duration and aerosol levels. The calculated inhaled mass corresponded to the source strength but not to the duration of the source activity. The total mass of aerosol potentially inhaled by an adult individual during the time outside the episodes was 1367 µg and during the episodes 2895 µg. During one hour, one person potentially inhaled approximately 36 µg and 294 µg of aerosol for the non-episode and the episode periods, respectively.