Abstract
OBJECTIVES: To investigate factors associated with indoor formaldehyde levels in office settings within an academic medical institute. METHODS: This cross-sectional study was conducted in 25 offices (261 workers) at a medical university in Thailand. Questionnaires gathered data on demographics, work patterns, and office equipment usage (printers, photocopiers, air fresheners, liquid paper, glue, cleaning agents, and marker pens). The building environment was assessed by a multidisciplinary team. Formaldehyde levels and relevant parameters (temperature and relative humidity) were measured in each room both indoors and outdoors. A multiple linear regression model investigated the relationship between formaldehyde and office factors, controlling for room conditions. RESULTS: Median office formaldehyde levels were 442.1 μg/m3 (interquartile range: 343.8-908.7 μg/m3), exceeding World Health Organization and Thai guidelines. Photocopier use was significantly associated with higher levels of indoor formaldehyde (β = .20; 95% CI, 0.30-0.37; P = .02). Air freshener use also showed a significant association (β = .56; 95% CI, 0.30-0.81; P < .001). No correlation was found between the use of liquid paper, glue, printers, cleaning agents, or marker pens and indoor formaldehyde levels. CONCLUSIONS: Indoor formaldehyde levels in these offices exceeded the established guidelines. Use of photocopiers and air fresheners was associated with increased formaldehyde levels. Implementing interventions such as improved ventilation and regular screening is essential for creating healthier office environments.