Asthmatics are more susceptible to fine particulate matters (PM2.5), compared to the general population. It has been reported that indoor PM2.5 is mainly generated by combustion of fossil fuels, meat or fish In particular, asthmatics are known to be more susceptible to indoor PM2.5 because 65 ∼ 95% of child or adult asthmatics stay inside the house. Thus, understanding the association between indoor activity patterns and variations in indoor PM2.5 levels is important. The purpose of this study is to determine the distribution of hourly indoor PM2.5 concentrations in asthmatics’ homes, and to evaluate its association with pan-frying cooking activity patterns, the most common PM2.5 emission related activity. From November 2017 to February 2018, real-time PM2.5 concentrations were measured in the living room of each asthmatic’s house (n = 35) for three weeks at 1 minute intervals. At the same time, self-reported daily activity patterns, hourly proportion (%) of cooking activities, were also recorded every hour over three weeks for each patient. In this study, we provided quantitative evidence that the distribution patterns of indoor hourly PM2.5 concentrations were associated with indoor cooking activities, especially in the homes of adult asthmatics. In addition, we observed that PM2.5 emitted by pan-frying could maintain even over up to 2 hour lagtime.