Heading into the dog days of summer, people spend more and more time indoors, and good air quality is a vital component of a healthy indoor environment. As a facility manager, this means special attention must be placed on attaining a high level of Indoor Air Quality (IAQ). Stressors are the chemical, biological, and physical agents that adversely affect building occupants (including perceived and actual annoyance or harm). The three primary types of stressors that should be considered as a facility’s IAQ program is developed include:
- allergens
- biological compounds
- infectious agents
Stressors cause physiological effects that vary in type and severity based on the body organs and systems affected and the sensitivity of the individual to the stressor. This article will discuss how the stressors affect IAQ, as well as possible consequences of not addressing these issues.
Allergens
Allergens are biological materials that contain proteins and other substances that elicit a response from the body, usually on sensitive membranes where the body contacts the environment (for example, the eyes, nose, sinuses, throat, and lungs). People who are allergic to a contaminant in their building usually experience relief from their symptoms when they leave the structure. Repeated exposure to contaminants may produce allergic responses at increasingly lower concentrations.
People respond in different ways when exposed to contaminants. Because of heredity or previous exposures, certain people are sensitive to particular chemicals or allergens. An allergic response to a contaminant at a low exposure level is known as sensitization. A sufficient number of people are affected by sensitization to make this issue a concern. Those who do become sensitized to a particular contaminant act as a barometer for the substance, responding with characteristic allergic reactions even when a minute amount of the contaminant is present. Three common allergens are:
- Penicillium: A common cause of an allergic response associated with HVAC systems. Penicillium mold grows in the cool, dark, moist environment found in interior-lined, air-conditioning ductwork. Penicillium releases spores that are spread throughout the HVAC system and building every time the HVAC cycles.
- Chemicals: There are many industrial cleaning chemicals, particularly chlorinated solvents, that can cause reactions. Algaecides and other biocides used in cooling towers and aesthetic fountains can also be sensitizers. Reactions to chemicals can include skin rashes, itching, drying, redness, sneezing, runny nose, nose bleed, asthma-like symptoms, headache, and irritability.
- Formaldehyde: A commonly used chemical that causes sensitization. Sensitized people respond to formaldehyde exposure with a variety of symptoms such as skin itching, rashes, hives, eye irritation, nose irritation and congestion, sneezing, chest tightness, cough, and headache.
To multiply, microorganisms need water, nutrients, and an acceptable temperature range. Some microorganisms also need oxygen. In addition, 95 percent of microorganisms need a surface on which to grow. Building systems and materials provide these basic needs.
Biological Compounds
Biological compounds, or biotoxins, are produced by microorganisms. These materials can be toxic and may be present in the indoor environment. Biotoxins cause a toxic response, as opposed to an allergic reaction. Many microorganisms can cause both infectious and allergic reactions in humans, depending on the susceptibility of the host. An example of a toxin produced by microorganisms is the toxin that causes botulism; the toxin is the cause of harm to those who are exposed to it.
Infectious Agents
Bacteria are biological, infectious agents that can infect the occupants of a building and thrive and spread in human tissue. These are simple one-cell organisms that can be transmitted by air and cause widely varying health effects. A number of illnesses and deaths have been attributed to bacteria. Although the most well-known agent, Legionnaires’ disease, attracted a lot of media attention, the threat it poses is minimal. Two less well-known, yet hazardous bacteria are:
- Rickettsias: Obligated parasites, which usually require fleas, ticks, mites, or lice to transmit them. Rickettsia bacteria occasionally become airborne and can be transmitted by that route. Typhus is an example of a disease caused by rickettsia.
- Chlamydiae: Obligated parasites that are smaller than rickettsias. These are readily transmitted by air and primarily affect the respiratory system. For example, bird droppings contain chlamydia, which becomes airborne when the droppings dry out and are disturbed by air currents or are cleaned up.
Viral agents are extremely small infectious agents that are readily transmitted by air and are biological hazards. For example, various forms of influenza are caused by viral infection. Of the 270 known viruses, 200 have been associated with respiratory illness. Viruses are also associated with the common cold, viral pneumonia, and general illness of the intestinal tract. These agents are predominantly spread through airborne droplets (caused by sneezing, for example). Viruses can also be transmitted through fomites, such as when an infected person sneezes or coughs on an object or surface (including their hand) and another non-infected person inadvertently transfers the secretions to their own mucous membranes by touching the eyes, nose, or mouth.
Damage that Stressors Can Cause
In nonindustrial or nonconstruction settings, the quantities of stressors in the indoor environment tend to be quite low. Because of this, stressors can be easily overlooked. The effects of these small amounts become a health concern when people are exposed all day, throughout the work week, over many years. In a small basement office, for example, a low airborne concentration of radon gas may continually be present. While the dosage is small, years of working in this space can increase the occupant’s risk for lung cancer.
Hypersensitivity diseases are characterized by allergic responses to antigens (substances such as toxins that can trigger an immune response). The diseases most clearly associated with sensitization are asthma, rhinitis, and hypersensitivity pneumonitis. Hypersensitivity pneumonitis (humidifier fever) is a rare but serious disease that progressively damages the lungs as long as the person affected is exposed to the causative agent. Humidifier fever was first associated with humidification systems, but has now been found throughout affected building systems where bacteria are able to flourish.
When sensitization reactions are extreme and a person is sensitive to a number of chemicals even at extremely low concentrations in the indoor environment, he or she has multiple chemical sensitivity. Current analytical instruments often fail to detect these ultra-low levels of contaminants. Although the medical community continues to debate whether this is a true affliction, research indicates that certain people may be sensitive to a large number of compounds. Many published studies have documented adverse reactions to fuels, paints, felt-tip marker solvents, typewriter correction fluid, and various perfumes.
Not addressing stressors can lead to Sick Building Syndrome complaints, declines in productivity, and health issues. IAQ problems can develop as a result of improper maintenance, modifications to controls, or through improper design of HVAC systems, but they can also occur in facilities where owners and managers conscientiously apply the best available practices to avoid these issues. Facility managers who can demonstrate ongoing efforts to provide a safe indoor environment are in a strong legal and ethical position if problems do arise.
This article is excerpted from BOMI International’s International’s Clean Air and OSHA Compliance Reference Guide. TMore information regarding this is available by calling 1-800-235-2664, or by visiting www.bomi.org.
