outbreak if certain conditions are met. various practices can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels that can facilitate mold growth. air filtration reduces the number of spores available for germination, especially when a high efficiency particulate air (hepa) filter is used. a properly functioning ac unit also reduces the relative humidity in rooms. the united states environmental protection agency (epa) currently recommends that relative humidity be maintained below 60%, ideally between 30% and 50%, to inhibit mold growth. eliminating the moisture source is the first step at fungal remediation. removal of affected materials may also be necessary for remediation, if materials are easily replaceable and not part of the load-bearing structure. professional drying of concealed wall cavities and enclosed spaces such as cabinet toekick spaces may be required. post-remediation verification of moisture content and fungal growth is required for successful remediation. many contractors perform post-remediation verification themselves, but property owners may benefit from independent verification. moldy housecorner from outside and inside mold stains on a gift card with package which was stored unintentionally for six months in an open compartment in a motorcycle use in art various artists have used mold in various artistic fashions. daniele del nero, for example, constructs scale models of houses and office buildings and then induces mold to grow on them, giving them an unsettling, reclaimed-by-nature look. stacy levy sandblasts enlarged images of mold onto glass, then allows mold to grow in the crevasses she has made, creating a macro-micro portrait. sam taylor-johnson, director of nowhere boy and fifty shades of grey (among others), has made a number of time-lapse films capturing the gradual decay of classically arranged still lifes.