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.
up vote 10 down vote accepted. Air does indeed flow from high pressure to low pressure area (see the wind arrows on a weather chart), but in the case of two rooms the much more important effect is that of warm thinner air rising towards the ceiling when the air from the two rooms gets mixed.