Personal exposure to particulate matter of aerodynamic diameters less than 2.5 μm (PM2.5) can be affected by various factors. The purpose of this study was to determine the impact of activity pattern and the contribution of each microenvironment to personal PM2.5 exposure. Technicians carried a nephelometer for PM2.5 while engaging in scripted time location activities. The scripted activities of 10 different population groups were based on time activity patterns of the Seoul population in Korea. A total of 58 daily PM2.5 personal exposures were available for analysis. The average PM2.5 personal exposure was 19.8 ± 15.3 μg m−3. The average personal exposure of each population group ranged from 9.8 to 43.1 μg m−3. High peak and average concentrations were observed in restaurants and bars; such high concentrations were due to secondhand smoke and cooking with charcoal on tables. The residential indoor level of the nine microenvironments was the largest contributor to personal exposure. The contributions from residential indoor, non-residential indoor, transportation, and outdoor levels were 36.2%, 53.4%, 6.7%, and 3.7%, respectively. The contributions of microenvironments varied among population groups; these variations suggest that the impact of activity pattern on personal exposure is significant.