The only effective way to control biological air contaminants like molds, fungi, dust mites, and bacteria is to control the cause. Repair any water leaks in the roof, walls or basement. Prevent condensation on walls and windows by maintaining a low relative humidity in your home, ideally 30-40 percent. Humidity levels are measured by hygrometers, which are available at hardware stores. Central air conditioning reduces humidity levels throughout the house.
Cool air holds less moisture than warm air.
But keep in mind that condensing the dampness that gets into the house increases your air-conditioning bills. Minimize the sources of dampness. Cooking, laundering, and bathing may add 3 gallons of water a day to the house. Install exhaust fans in bathrooms and in the kitchen. Make sure that your clothes dryer is exhausted to the outside.