According to the Environmental Protection Agency (EPA), mildew refers to certain kinds of mold or fungus. The term mildew is often used generically to refer to mold growth, usually with a flat growth habit.
Molds include all species of microscopic fungi that grow in the form of multicellular filaments, called hyphae. Molds can thrive on any organic matter, including clothing, leather, paper, and the ceilings, walls, and floors of homes with moisture management problems.
Mildew often lives on shower walls, windowsills, and other places where moisture levels are high. There are many species of molds. In unaired places, such as basements, they can produce a strong musty odor.
It is easy to confuse mold with black dirt or dust. Dirt and dust is easily wiped off with a clean cloth.
Mold is a type of fungus that has a distinct, damp smell, needs moisture to grow, and can attach itself to walls and other vertical spaces. The smell is similar to rotting wood, wet dog, or soggy cardboard. Mold reproduces via tiny spores that spread through the air, on clothing, or on dust particles.
Dust contains dead skin cells, hair, pollen, bacteria, dead insects, and minutes traces of plastic. It settles on low surfaces as it is pulled down by gravity. It does not have the ability to attach itself to vertical surfaces. Mold can grow on dust particles.
Mold is often furry or velvety in appearance and presents a more uniform ‘growth” rather than a collection of dust particles.
Dirt is a medium for mold to grow. It has an earthy odor.
Per Centers For Disease Control and Prevention (CDC), “color is not an indication of how dangerous a mold may be. Any mold should be removed and the moisture source that helped it grow should be removed. Certain molds are toxigenic, meaning they can produce toxins (specifically “mycotoxins”). Hazards presented by molds that may produce mycotoxins should be considered the same as other common molds which can grow in your house. Not all fungi produce mycotoxins and even those that do will not do so under all surface or environmental conditions.