Elevated symptom prevalence associated with ventilation type in office buildings

Area of Science:

• Environmental Health
• Occupational Health
• Building Science

Background:

• Ventilation systems significantly impact indoor air quality and occupant health.
• Previous research primarily from Europe suggested links between ventilation types and worker symptoms.
• U.S. building data were needed to confirm these associations.

Purpose of the Study:

• To investigate the relationship between different ventilation system types (natural, mechanical, air-conditioned) and office worker symptoms in U.S. buildings.
• To compare symptom prevalence across ventilation types, adjusting for confounding factors.
• To provide U.S.-specific evidence supporting or refuting previous international findings.

Main Methods:

• A cross-sectional study of 880 office workers in 12 northern California public buildings (3 naturally ventilated, 3 mechanically ventilated, 6 air-conditioned).
• Data collection via questionnaires on worker symptoms, personal, job, and workplace factors.
• Statistical analysis using logistic regression and mixed effects models (SAS/GLIMMIX) to adjust for confounders and correlated responses.

Main Results:

• Higher adjusted prevalence of most symptoms, particularly dry/itchy skin and lower respiratory issues, were associated with mechanical and air-conditioned ventilation compared to natural ventilation.
• Odds ratios for dry/itchy skin were 6.0 for both mechanical and air-conditioned systems.
• Odds ratios for lower respiratory symptoms were 2.9 for mechanical and 4.0 for air-conditioned systems.

Conclusions:

• Mechanically ventilated and air-conditioned office buildings in the U.S. are associated with increased prevalence of certain worker symptoms.
• Findings support previous European studies, highlighting potential health impacts of ventilation system types.
• Implications for building design and management to improve indoor environmental quality and worker well-being.