Aspergillus niger is a common fungus found in various environments, including soil, decaying plant matter, and indoor spaces. It appears as a black mold and is known for its ability to thrive in diverse conditions. This species is often used in industrial applications, particularly in the production of enzymes and organic acids, such as citric acid. While Aspergillus niger is generally not harmful to healthy individuals, it can pose health risks to those with weakened immune systems or respiratory issues. Exposure may lead to allergic reactions or infections, making it important to manage its presence in indoor environments.