Heated tobacco products (HTP) have become increasingly popular in Japan, and reports on environmental exposure to HTP exhaled aerosol have been increasing accordingly. However, there is a limited number of studies that investigated the current status of the exposure. In addition, environmental exposure studies based on surveys analysis include several limitations. For example, respondents’ imprecise memory recollection and inaccurate responses. The purpose of this study was to investigate the current status of environmental exposure to HTP exhaled aerosol in detail and to examine the methodology to improve response accuracy. This study was an Internet-based survey conducted on 30,000 non-smokers aged 20 to 69 in Japan. The status of exposure was calculated by providing the proportion of non-smoker individuals around, i.e., bystanders, who reported having the opportunity to inhale the exhaled aerosol from the HTP users, and subsequently classified by place, e.g., home, workplace. The response proportion of tobacco types (HTP, Cigarette, Unknown) to which respondents were exposed, along with the response proportion of exposure initiation time and the inconsistency response proportion for paired similar questions were examined to improve response accuracy. The results indicated that the proportion of exposure was the highest at home (1.96 %) among investigated places. The response proportion of tobacco types was the highest at home (87.7 %). At all investigated places, the response proportion of the exposure initiation time among those who could respond, tobacco types were higher than those who could not. The inconsistency proportions investigated were ranged from 3.8 % to 22.3 %. This study suggested that a survey focusing home where non-smokers can identify tobacco products users easily would be appropriate when investigating the status of environmental exposure to HTP exhaled aerosol, and that identifying inconsistent responses among similar questions would contribute to improving response accuracy.