Abstract: An air purifier and a passive humidity module for inside air. The air purifier includes a housing and an air purifier air outlet. The passive humidity module is disposed at least partially on the air purifier air outlet. The passive humidity module includes a housing assembly defining an air inlet and an air outlet, a water tank supported by the housing assembly, a wick filter reservoir fluidly coupled to the water tank, at least one gutter fluidly coupled to the water tank, and a wick filter disposed in the wick filter reservoir and supported by the housing assembly. The air inlet is at least partially aligned with the air purifier air outlet. The passive humidity module includes an airflow path flowing between the water tank and the wick filter, and fluidly connecting the air inlet and the air outlet.