This study describes a presentation technique of scent designed for users to recognize multiple scents during a very short time period. We measured the olfactory characteristics of subjects when two kinds of scents were presented in a single breath. We defined and measured the minimum ejection interval in which subjects could discriminate the two individually emitted pulses of scent, which we term "separable detection threshold", and the minimum ejection interval in which they could specify both kinds of scents, "separable recognition threshold". Further, "response time" and "duration of scent perception" were measured. As a result, we found the duration of scent perception and the separable recognition threshold were positively correlated. Knowledge of this olfactory characteristic brings us closer to being able to provide a greater sense of realism in multimedia environments, by describing more than one object by scent at the same time as the objects are seen on screen.