Dennis K Ledford, M.D., Associate Professor of Medicine, University of South Florida

Modern Americans spend more than 90% of their time with indoor environments. It is no surprise that various health problems, primarily respiratory, have been attributed to indoor environmental contact. These health problems range from defined medical illnesses to poorly defined syndromes. Proven medical conditions caused by the indoor environment include infectious illnesses such as Legionnaire's disease, Pontiac fever, tuberculosis and viral illnesses.

Environmental immunologic diseases are both allergic and non-allergic. The allergic problems are allergic rhinitis and asthma, related to indoor allergens such as dust mite, cockroach, animals and mold. Irritants such as certain volatile hydrocarbons may aggravate existing asthma via non-immunologic mechanisms. Temperature changes, certain irritants, and strong smells may aggravate vasomotor rhinitis. This type of rhinitis mimics allergic rhinitis. Rarely allergic skin conditions such as eczema or urticaria may be related to indoor environments, usually when large quantities of organic materials are involved or when insect infestations lead to skin trauma. Hypersensitivity pneumonitis is a non-allergic, immunologic pulmonary disease resulting from the inhalation of organic dusts from contaminated humidifiers, moldy organic debris, animal proteins and certain chemicals. This disorder is often misdiagnosed as an acute infectious respiratory condition because of the fever, chest infiltrates and cough. Interstitial fibrosis with permanent scarring of the lung may result if repeated acute episodes occur or chronic, low-grade exposure is permitted.

Humidifier fever may be a less severe form of hypersensitivity pneumonitis but does not result in scarring of the lung.

Building related complaints include syndromes of collections of symptoms occurring with increased frequency in part or all of a selected building. The so-called "sick building syndrome" is an example of these syndromes. The etiology of the symptoms are usually due to some environmental feature(s) of the building, but the exact cause is difficult to ascertain. Potential causes include poorly functioning ventilation systems with inadequate fresh air, inorganic chemicals such as ozone or nitrogen dioxide and organic chemicals such as mycotoxin or formaldehyde. The symptoms often include mucosal irritation, skin irritation, neuropsychiatric complaints of fatigue and limited ability to concentrate and odor and taste complaints.

The objective evidence that the indoor environment is responsible for building related complaints is often lacking. There is a need for additional research and understanding, but the current status of the problem is that each individual or group of individuals should be evaluated in an objective, scientific manner.

For more information, contact:
Alan L. Wozniak, CIAQP
(800) 422-7873 ext. 802
iaq@pureaircontrols.com