“Sick Building Syndrome” (SBS) describes acute health effects linked to time spent in a specific building. Symptoms often include headaches, fatigue, dizziness, and respiratory irritation, which lessen or disappear shortly after leaving the structure. Causes are complex but generally fall into categories of biological, chemical, or physical contamination. This article categorizes the most common household culprits that degrade indoor air quality and affect health.
Illnesses Stemming from Moisture and Biology
Consistently high humidity and water intrusion create breeding grounds for biological contaminants. Mold and mildew are common offenders, thriving when relative humidity exceeds 60%, though growth can begin above 50%. These fungi reproduce by releasing microscopic spores and sometimes producing mycotoxins. Exposure can trigger allergic reactions, such as sneezing, runny nose, and eye irritation, or cause asthma episodes and chronic respiratory issues.
Dust mites are another significant source of allergens, flourishing in warm, moist areas like bedding, carpets, and upholstered furniture. The reaction is caused not by the mite itself, but by potent digestive enzymes found in its fecal droppings and decomposed body fragments. Inhaling these particles causes year-round allergies, leading to wheezing, coughing, and sometimes skin irritation or eczema.
Biological growth also occurs within heating, ventilation, and air conditioning (HVAC) systems. Condensate pans and cooling coils provide the moisture necessary for bacteria and fungi to multiply. For instance, the bacteria Legionella can thrive in water systems and, if aerosolized, cause severe respiratory infections like Legionnaires’ disease. Regular maintenance prevents the circulation of these airborne microorganisms.
Invisible Chemical and Gas Exposures
The home environment can be compromised by odorless or invisible substances that off-gas from materials and appliances. Volatile Organic Compounds (VOCs) are chemicals emitted as gases from solids and liquids used in construction and maintenance. Sources include new paint, carpeting, vinyl flooring, cleaning supplies, air fresheners, and engineered wood furniture.
Indoor concentrations of VOCs can be up to ten times higher than outdoor levels. Exposure causes both short-term discomfort and long-term health problems, with immediate symptoms including eye, nose, and throat irritation, headaches, and dizziness. Extended exposure to certain VOCs, such as formaldehyde or benzene, is associated with damage to the central nervous system, liver, and kidneys.
Carbon Monoxide (CO) is an immediate hazard, an odorless, colorless gas produced by the incomplete combustion of carbon-based fuels. Common sources include faulty furnaces, gas water heaters, wood stoves, and cars left running in an attached garage. When inhaled, CO binds to hemoglobin more effectively than oxygen, rapidly starving organs of oxygen. Low-level exposure mimics the flu with fatigue and headaches, while high concentrations quickly lead to loss of consciousness and death.
Radon is a naturally occurring radioactive gas resulting from the breakdown of uranium in soil and rock. It seeps up through foundations and cracks, accumulating indoors, particularly in basements and ground-level rooms. Radon is the second leading cause of lung cancer in the United States, second only to smoking. Since it is undetectable by human senses, specialized testing is the only way to determine elevated levels.
Airflow, Filtration, and Particulate Irritants
Air movement and the presence of fine particles play a substantial role in indoor air quality. A lack of proper ventilation allows pollutants to become concentrated, leading to physical and cognitive complaints. When air exchange is inadequate, exhaled Carbon Dioxide (CO2) accumulates, causing drowsiness, fatigue, and difficulty concentrating when levels exceed 1,000 parts per million (ppm).
Stagnant air permits the buildup of common particulate irritants, which are physical substances that can be inhaled. These include household dust, fine soil particles, pet dander, and external pollutants like pollen and traffic exhaust. These particles irritate the respiratory system, worsening pre-existing conditions like asthma and allergies.
Managing irritants depends on the proper function of the home’s heating and cooling system. HVAC air filters are rated using the Minimum Efficiency Reporting Value (MERV) scale, which indicates effectiveness at capturing particles. Filters rated MERV 8 capture basic particles like dust and pollen. Filters rated MERV 11 are suitable for pet owners and those with mild allergies, capturing smaller particles like pet dander and some bacteria, while MERV 13 offers superior filtration. Homeowners must verify their HVAC system can handle the increased airflow resistance before upgrading to a higher MERV rating.
Practical Steps for Environmental Remediation
Addressing the causes of a sick home requires a systematic approach starting with continuous monitoring. Installing carbon monoxide detectors on every level and near sleeping areas is an immediate safety measure against acute gaseous threats. Homeowners should purchase a hygrometer to track relative humidity, aiming to keep the level consistently between 30% and 50% to discourage biological growth.
Specialized testing is necessary for environmental concerns that cannot be detected by the senses. Radon test kits are readily available and provide the only way to measure the concentration of this radioactive gas. If humidity is controlled and ventilation is confirmed, yet symptoms persist, a professional environmental testing service may be needed to check for high levels of VOCs.
The most effective solution is source removal rather than merely treating symptoms. This involves fixing leaks and water damage immediately, upgrading to a supported higher-rated MERV filter, and increasing ventilation using exhaust fans or opening windows when using chemical products. If mold is extensive or if CO or radon levels are dangerously high, consulting a certified mold remediation specialist or an HVAC professional is necessary to resolve the underlying problem.