Bioaerosols in the Environment

Bioaerosols are small living organisms or particles of living things suspended in the air. Included in this category are; dust mites, molds, fungi, spores, pollen, bacteria, viruses, human and pet dander (that has been shed) are just some examples. They are so tiny that they cannot be seen by the naked eye. Instead must be viewed under a microscope or with the aid of a magnifying glass.

A commonly asked question is, “Can Bioaerosols cause health problems?” We would like to respond by confirming these minute particles do play a large role in creating potential health risks especially to those individuals who are immunocompromised as well in cases where exposure may cause infection and/or allergies. In any event, both situations need to be treated with immediate concern. In some cases if left untreated allergic responses and/or infection as a result of exposure to specific Bioaerosols may be serious and even fatal.

What is an allergic reaction?

An allergic reaction occurs when a substance provokes the formation of antibodies in a susceptible individual. These substances are referred to as “antigens” or “allergens”. Reactions may appear on the skin or in the respiratory tract. Rashes, hay fever, asthma, runny noses are commonly listed allergic reactions.

There are of course a few people who may develop a severe reaction in the lung, which can destroy tissue. This reaction is known as hypersensitivity pneumonitis. Though not readily an infection, it can lead to an infection known as bacterial pneumonia as a result of repeated episodes. Hypersensitivity pneumonitis can be triggered easily after an individual becomes sensitized, that is to say even small amounts of the allergen will cause a reaction once a person is sensitive to it. Symptoms can range from tightness in the chest, cough, and difficulty in breathing, to low-grade fever, muscle aches, and headaches.

What are common sources of Bioaerosols found in the home?

Molds, mildews, bacteria, and dust mites like the same conditions that we do. A warm environment with moderate to high humidity. Which is one reason we suffer allergic reactions during the summer months. Bacteria, molds, and mildews are commonly identified within air conditioning units/equipment, humidifier reservoirs, dehumidifier drip pans, showerheads, toilets, and ice machines. Water damaged materials such as carpets, ceiling panels; walls and paneling are all key sites, which provide conducive growth environments for new growth if they are allowed to stay damp.
Note: When molds, mildew, dust mites, and bacteria are disrupted or release their spores into the air, this results in Bioaerosols formation.

What measures can be taken to control Bioaerosols in the home?

First of all, lower the level of humidity in your home, basement, crawl space, and attic. (Relative Humidity is the amount of moisture in the air at a given temperature.) Humidity fluctuates in your home, depending upon:

• How warm or cool the air is indoors.

• How many moisture-producing activities (drying clothes indoors, showers etc.) that are taking place.

• Sources of moisture (leaks, dampness, foundations/attics).

• Ventilation: How much is being vented to the outside.

To effectively manage the causes of Bioaerosols in the home consider the following as a guide:

• Reduce relative humidity

• Eliminate sources of moisture such as leaks.

• Dry the air. The use of a chemical or mechanical dehumidifier. Empty collecting drip pan daily!

• Open closet doors to allow air to circulate. Use a 40-watt light bulb to dry and heat the air in the closets.

• Vent bathrooms and clothes dryers to the outside.

• Trim back trees and shrubs around the house to reduce shade.

• Remove debris from your yard, roof and gutters.

• Clean mold and mildew growth from walls with water mixed with chlorine bleach, diluted three parts water to one part bleach. Commercial products can also remove mold and mildew. Follow product instructions carefully.

• Check heating and cooling system filters monthly or as needed based on visible appearance.

• Vacuum air return covers or screens regularly.

• Check air conditioners for mold before each cooling season and have coils cleaned as needed.

• Have heating/cooling system ductwork checked for loose insulation, leaks, or signs of condensation where the system enters the house.
  Note: Insulate ducts on the outside of the ductwork.

• Air cleaners and filters are other options. Electronic and HEPA (high efficiency particulate absolute) cleaners and filters are the best at taking mold, mildew, and dust out of the air.

• Make sure that crawl space vents work and are not blocked.

• Mechanical dehumidifiers reduce humidity in basements.

In addition to the above recommendations it is required that relative humidity be maintained below 50 percent to effectively manage/limit the control of the dust mite population. In summary, Bioaerosols, such as molds, mildew, and dust mites, are commonly found in indoor air. Control measures include reducing the sources of moisture, reducing the relative humidity, and removing materials, which could contribute to the growth of these agents.