Indoor Air Quality is affected by biological contaminants. They include bacteria, viruses, animal dander and cat saliva, house dust, mites, cockroaches, and pollen. There are many sources of these pollutants. By controlling the relative humidity level in a home, the growth of some sources of biologicals can be minimized. Relative humidity of 30-50 percent is generally recommended for homes. Standing water, water-damaged materials, or wet surfaces also serve as a breeding ground for molds, mildews, bacteria and insects. House dust mites, the source of one of the most powerful biological allergens, grow in damp, warm environments.
Indoor Air Quality
Pollens originate from plants.
Viruses, which people and animals transmit.
Mold
Bacteria, which people, animals, and soil and plant debris carry.
Household pets, which are sources of saliva and animal dander (skin flakes)
Droppings and body parts from cockroaches, rodents, and other pests or insects
Viruses and bacteria
The protein in urine from rats and mice is a potent allergen. When it dries, it can become airborne.
Contaminated central air handling systems can become breeding grounds for mold, mildew and other sources of biological contaminants and can then distribute these contaminants through the home.
Many of these biological contaminants are small enough to be inhaled.
Biological contaminants are or are produced by, living things. Biological pollutants are often found in areas that provide food, moisture, or water. For example:
Wet areas like cooling coils, humidifiers, condensate pans, or unvented bathrooms can be moldy.
Draperies, bedding, carpet, and other areas where dust collects may accumulate biological contaminants.
Health Effects from Biological Contaminants
Some biological contaminants trigger allergic reactions, including:
Hypersensitivity pneumonitis
Allergic rhinitis
some types of asthma
Infectious illnesses like influenza, measles, and chicken pox are transmitted through the air. Molds and mildews release disease-causing toxins. Symptoms of health problems caused by biological pollutants include:
Sneezing
Watery eyes
Coughing
Shortness of breath
Dizziness
Lethargy
Fever
and digestive problems
Allergic reactions occur only after repeated exposure to a specific biological allergen. However, that reaction may occur immediately upon re-exposure or after multiple exposures. As a result, people who have noticed only mild allergic reactions, or no reactions at all, may suddenly find themselves very sensitive to allergens.
Some diseases, like humidifier fever, are associated with exposure to toxins from microorganisms that can grow in large building ventilation systems.