Humidity control involves regulating the moisture content in the air. Depending on the environment, dehumidifiers, which draw extra moisture from the air, or humidifiers, which add more moisture to the air. Humidity can also be controlled by changing environmental exposures or behaviors, such as vents and leaks, time spent in a hot shower, and the number of plants located in an indoor area. The EPA recommends indoor humidity be maintained between 30 and 50% to prevent mold and pests.