Biological Contaminants
Biological contaminants include bacteria, molds, mildew, viruses, animal dander and cat saliva, house dust, mites, cockroaches, and pollen. Biological contaminants can come from the outdoors or be generated indoors.
Children, elderly people, and people with breathing problems, allergies, and lung diseases are particularly susceptible to disease-causing biological agents in the indoor air.
In addition to harming people’s health, indoor biological contaminants and moisture problems can compromise a building’s structure and reduce its lifespan. For example, mold can deteriorate building materials, and pests can cause damage by eating building materials or creating nests. These problems can be costly if not addressed.
Health Effects from Biological Contaminants
Symptoms of health problems caused by biological pollutants include sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fever, and digestive problems.
- Some biological contaminants trigger allergic reactions, including hypersensitivity pneumonitis, allergic rhinitis, and some types of asthma.
- Mold, dust mites, pet dander, and pest droppings or body parts can trigger asthma.
- Infectious illnesses, such as influenza, measles, tuberculosis, and chicken pox are transmitted through the air.
- Molds and mildews release disease-causing toxins. Some diseases, like humidifier fever, are associated with exposure to toxins from microorganisms that can grow in large building ventilation systems. However, these diseases can also be traced to microorganisms that grow in home heating and cooling systems and humidifiers.
Reducing Exposure to Biological Contaminants
Reducing Exposure to Biological Contaminants
The following three strategies for improving indoor air quality can prevent or minimize biological contaminants indoors:
- Control sources of contaminants: Prevent conditions that allow biological contaminants to multiply or make their way indoors and manage known biological contaminants present indoors, like pest management and regular dusting/vacuuming. Usually, this is the most effective way to address indoor air quality problems.
- Ventilation: Dilute and remove biological pollutants from indoor air. This is typically achieved by bringing in outdoor air — when outdoor conditions allow and it is safe to do so — as well as using kitchen and bathroom exhaust fans when appropriate.
- Filtration and Air Cleaning: Supplement source control and ventilation with filtration and air cleaning technologies to help remove biological pollutants from the air.
- Control the humidity: By controlling the relative humidity level in a home, the growth of some sources of biologicals can be minimized. A 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. Moist areas, such as poorly ventilated bathrooms, can encourage the growth of biological contaminants, like mold, and attract pests.
- Close the gaps: Biological contaminants can make their way indoors through windows, doors, poorly maintained ventilation systems, plumbing and cracks and holes in a building’s exterior and foundation.