From Frederick, MD to Washington, DC, keeping your home air ducts clean is important because the ducts can become a major source of indoor air pollution. Every time you run your heating and cooling system, airborne contaminants, including dust, pet dander, pollens and molds, are pulled into the ducts. Over time, these contaminants build up inside the duct work, creating a breeding ground for mold, bacteria, fungi and other microbes. These contaminants can also significantly decrease the efficiency of your heating or cooling system.