A light guide plate 13 has a number of back surface-side unit optical structures 131 arranged in a back surface 13d along a light guide direction. An airflow is created through the reservoir via the exhaust gasflow from the vacuum cleaner, the airflow carrying the atomized liquid via an elongate tube to dispensing outlet provided on a cleaning head of the vacuum cleaner. The air purifier also includes at least one microwave radiation source and at least one ultraviolet radiation source which work in combination to increase the effectiveness of the antimicrobial ions.