Did you know: about 40,000 dust mites can «thrive» in only one ounce of dust. Imagine how many are living in your ductworks? Dust mites are in your home and mine. They are tiny insects that are so small they are invisible to the naked eye. However their feces and body parts are proven to cause asthma attacks for people who are allergic to them. According to the US EPA exposure to dust mites can cause asthma in children who previously have not exhibited asthma symptoms.