Fungal nail infections can be caused by three different types of fungus, alone or in combination. 1  Dermatophytes are a type of fungus that can grow on the skin, hair, and nails. 2  They don't invade the deeper tissues of the body. 3  The most common dermatophyte, Trichophyton rubrum, causes most cases of athlete's foot.
Negative Airflow. Negative airflow is the opposite of postive airflow its having more exhaust fans then intake fans, this is good because its always taking new air into the case, but then you have more dust because the intake is mostly coming from gaps in the case and then causing trapped air.
3) incoming air over the coil is so cold or airflow is so low that it drops well below freezing at the coil surface - usually an indication of a fan not running or running at low when it should be at high, or an airflow blockage from a mostly closed duct damper or a plugged or too restrictive a filter so the airflow over the unit is too low for its rated heat transfer capacity, causing it to run well below freezing and frosting up from the moisture in the air passing over it