Arthrinium: Primarily a plant pathogen found in soil and decomposing plant matter. Although it is not commonly found indoors, one species has been identified as an allergen.

Ascospores: These spores are abundant in nature and present everywhere, especially in outdoor environments associated with rain and moisture. Some species can thrive indoors on damp materials and have allergenic potential, though this varies based on the species.

Fusarium: Typically found indoors under extremely wet conditions, Fusarium can be present in dust, carpets, mattresses, damp walls, wallpaper, and duct liners. It can trigger allergic reactions, such as hay fever and asthma.

Stachybotrys: Often referred to as “toxic black mold,” Stachybotrys thrives indoors on water-damaged cellulose-containing materials like sheetrock, paper, and ceiling tiles. It produces mycotoxins that may cause discomfort in the mouth, throat, and nasal passages. Chronic exposure can lead to more severe health issues like headaches, diarrhea, memory loss, and brain damage.

Botrytis: A plant pathogen typically found on vegetation in temperate and subtropical climates. It can also grow on indoor plants and cause hay fever and asthma effects as a potential allergen.

Chaetomium: Commonly found indoors on water-damaged cellulose-containing materials like paper, sheetrock, and wallpaper. Although not extensively studied, it is suspected to be an allergen causing hay fever and asthma effects.

Cladosporium: One of the most prevalent genera in both indoor and outdoor environments. Cladosporium thrives in damp areas and condensation-prone spots, often found on textiles, window sills, bathrooms, and air conditioning systems. It is a common airborne allergen.

Aspergillus/Penicillium-like: Two of the most widespread genera in the world, found both indoors and outdoors. Indoors, they may appear on water-damaged wallpaper, carpet, and other organic materials, particularly in high humidity conditions. Many species are allergens, causing respiratory irritation, while some can even be pathogens leading to infections in humans and animals.

Basidiospores: Primarily comprising mushrooms and shelf fungi, Basidiospores are typically found outdoors. In indoor settings, they may grow on any organic matter causing dry rot and may trigger allergies in sensitive individuals.

Bipolaris/Dreschlera: These plant pathogens are commonly found outdoors on grasses, grains, and decaying food. Indoors, they can affect plants and building materials, causing allergies that affect the nose, skin, eyes, and upper respiratory tract.