750 Introduction to Industrial Hygiene

Indoor Environmental Issues

Employee complaints can be due to two types of health issues related to the indoor work environment: sick building syndrome and building related illnesses.

Sick Building Syndrome

Sick building syndrome (SBS) is caused by a combination of indoor environmental, design, and operational factors in buildings that lead to health symptoms in occupants.

While no single factor is solely responsible, the interplay of the elements below—especially poor ventilation and chemical or biological contaminants—is most commonly implicated. The primary causes include:

1. Poor Indoor Air Quality (IAQ):
• Inadequate Ventilation: Insufficient fresh air circulation, often due to tightly sealed buildings or poorly maintained HVAC systems, leads to a buildup of pollutants. Studies suggest ventilation rates below 10 liters per second per person increase SBS risk.
• Chemical Contaminants: Volatile organic compounds (VOCs) from paints, adhesives, carpets, cleaning agents, or office equipment (e.g., printers) can trigger symptoms. Formaldehyde and other emissions from building materials are common culprits.
• Biological Contaminants: Mold, bacteria, and fungi, often caused by moisture from leaks, condensation, or high humidity, can release allergens or toxins. For example, a 2019 study in Japan linked musty odors and mold to SBS symptoms.
2. Physical Factors:
• Temperature and Humidity: Extreme temperatures (too hot or cold) or improper humidity levels (too high or low) can cause discomfort and exacerbate symptoms like dry eyes or respiratory issues.
• Lighting: Poor or flickering lighting, especially fluorescent lights, can lead to eye strain, headaches, and fatigue.
3. Indoor Design and Maintenance:
• Poor Building Design: Sealed windows, lack of natural light, or improper air circulation systems can trap pollutants and reduce air quality.
• Neglected Maintenance: Dirty air filters, clogged ducts, or unaddressed water damage can foster pollutant buildup or microbial growth.
4. Occupant-Related Factors:
• High Occupant Density: Crowded spaces increase CO₂ levels and reduce air quality, worsening symptoms.
• Sensitivity to Pollutants: Some individuals are more sensitive to low-level exposures, and stress or psychosocial factors in the workplace can amplify perceived symptoms.

Building-Related Illnesses

Building-related illnesses are health problems that doctors can clearly diagnose and trace to a specific cause. Examples include infections such as legionellosis and hypersensitivity diseases.

• Legionellosis: Legionellosis is a lung infection caused by breathing in water droplets (aerosols) that contain Legionella bacteria. It can cause a serious type of pneumonia called Legionnaires’ disease or a milder, flu-like illness called Pontiac fever. Common sources include cooling towers, hot water tanks, humidifiers, and air conditioning systems.
• Hypersensitivity Disease: A hypersensitivity disease is an allergic-type reaction that happens when the body’s immune system overreacts to a substance, such as mold, dust, or chemicals. In workplaces and buildings, this can include conditions like hypersensitivity pneumonitis (an inflammation of the lungs caused by inhaling organic dusts) or allergic rhinitis (hay fever-type symptoms)

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