It is possible that the fresh air is carried into a room with a single-sided opening, where airflow is induced parallel to the plane containing the opening. However, when one room at windward side has contamination source in itself, it is possible that the airflow including contaminated air reaches openings of other rooms at leeward side. In this study, the characteristics of cross contamination to a leeward opening due to a windward opening are analyzed through wind tunnel experiment. In some experimental cases, the shape of opening is changed in order to determine the relationship with the cross contamination. The shape of windward opening is important factor of the cross contamination. In other experimental cases, square bars are attached in order to prevent the cross contamination. The room mean concentration with square bars shows a 30% decrease compared to the case without square bars.
