By allowing air and sun to penetrate your building daily. Moulds are a type of fungi and do not get energy through photosynthesis but from the organic matter on which they live. Their presence is only visible to the human eye when mould colonies grow. The simplest way to mitigate mould growth is to reduce the moisture levels which facilitate its growth. If a building or area already has the presence of moisture and is left in the dark it is likely to produce mould. Aeration, cleanliness and sunlight are the simplest ways to counteract this moisture build-up and to reduce the stability of the temperature and humidity in the environment which is particularly attractive to moulds.