A musty smell is typically caused by the growth of mold or mildew. Mold and mildew are types of fungi that thrive in damp, humid environments, and can grow on a variety of surfaces, including wood, fabric, and paper. When mold and mildew grow, they release microbial volatile organic compounds (MVOCs), which can produce a musty or earthy odour.

Here are some common causes of musty smells:

Dampness: Moisture is the primary factor that promotes the growth of mold and mildew. Areas with high humidity or inadequate ventilation, such as basements, attics, and bathrooms, are particularly susceptible to musty smells.
Water damage: Water damage from leaks, floods, or plumbing issues can also lead to musty smells. When water seeps into building materials, it can create ideal conditions for mold and mildew to grow.
Poor air circulation: Poor air circulation can trap moisture and prevent it from drying out, creating an environment where mold and mildew can thrive. This can happen in areas that are poorly ventilated or have restricted airflow, such as closets or storage spaces.
Dirty or damp fabrics: Fabrics that are damp or soiled can also develop a musty smell. This can happen with clothing that has been left in a damp area or with towels and linens that have not been properly dried.
Old or unused spaces: Musty smells can also occur in areas that have been unused for an extended period, such as vacation homes, storage units, or rental properties.
To eliminate musty smells, it is important to identify and address the underlying cause. This may involve fixing leaks or water damage, increasing ventilation, or using dehumidifiers or air purifiers to reduce humidity and improve air quality.

air circulation Dampness humidity mildew moisture mold musty MVOCs