In order to control and reduce human exposure to particulate pollution, information on indoor particle characteristics is of substantial importance due to the fraction of time people spend indoors.  Most of the current exposure models use outdoor concentrations of pollutants to predict the total human exposure, however, there is growing evidence that indoor air varies significantly from outdoor even if there is no indoor source. A sizeable number of studies have been conducted on various features of indoor particulate matter but most of them are lacking in providing information on continuous spatial and temporal variation in concentration of fine particulates and factors responsible for them. Studies on simultaneous and continuous measurement of mass and number concentration of particulates and factors affecting the indoor levels of PM are limited.  Hence, there is a need to evaluate the PM concentrations by considering all those factors, which affect their indoor levels in a wide range of indoor settings.