Abstract: The upper cylinder with several holes perforated in the base is inserted and bolted to the lower cylinder with several holes perforated in the upper part of the wall of the larger cylinder. A circular damper plate is placed on top of the upper cylinder to prevent splashing of the water. A holding plate accommodating the two cylinders is placed into the heating and air conditioning system, in the spot where the conventional mesh filters are usually placed. Then water and paraffin is poured into the cylinders. The incoming air flows through the water and paraffin bath and traps all dust, dust mites, pollutants, bacteria and particulate matter. A water reservoir maintains the correct water level in the cylinders, by connecting an air pipe as a sensor and a water pipe as a water supply.