It is these biological organisms that are most likely to cause health problems. Allergic reactions are most commonly associated with biological pollutants. Symptoms include watery eyes, runny noses and sneezing, nasal congestion, itching, coughing, wheezing and difficulty breathing, headache, dizziness and fatigue. Molds, mildew pollen, fungi, bacteria and dust mites are the main biological pollutants. Mold and mildew are generated in the home and release spores into the air.
Pollen is generated outside the home.
Dust mites and animal dander are problematic when they become airborne during vacuuming, making of beds or whenever textiles are disturbed. Dust mites are the single most frequent trigger for asthma attacks. Molds thrive in areas of high humidity on organic materials such as paper, textiles, grease, dirt and soap scum. Mold spores float throughout the house, forming new colonies where they land. Dust mites thrive on dead human skin cells and in textiles, such as bedding, carpeting and upholstery.