Objective: To determine the concentration of fluctuating gaseous formaldehyde in an anatomy laboratory and to investigate its effects on the subjective symptoms and the lung functions of medical students working there.
Methods: To measure the levels of formaldehyde gas at different physical ventilation times at the center of the study laboratory by the gaseous formaldehyde detector. A total of 251 of second-year medical students were randomly selected from 1004 students participating in the anatomy operation as the survey subjects, 77 medical students were randomly selected for lung function assessment. The subjective symptoms of the medical students exposed to this gas were investigated via questionnaire surveys before, during and after the dissection operation. The probable lung function damages caused by the exposure before and after the operation were also measured using various parameters.
Results: The concentration of gaseous formaldehyde decreased with an increase in the ventilation time(P<0. 05), but it was always higher than the occupational health standard(0. 50 mg/m~3). The gas concentration above the dissecting table(0. 43-2. 89 mg/m~3) was significantly higher than that at the center of the laboratory(0. 34-2. 31 mg/m~3)(P<0. 05). The levels of the gas in the thoracic and abdominal cavities(0. 67-2. 89 mg/m~3) were significantly higher than those in the superficial fascia(0. 50-2. 13 mg/m~3) and deep layer of the back(0. 34-1. 48 mg/m~3)(P<0. 05). When compared with that at the pre-operative period, the prevalence of most subjective symptomssuch as itchy eyes, nasal congestion, runny nose, dyspnea, headache, and lack of energy increased significantly during the operation and decreased thereafter(P<0. 05). After the procedure, forced expiratory volume 1(FEV1)/forced vital capacity(FVC), FEV1, peak expiratory flow(PEF), FEF25%-75%, maximum expiratory flow 25%(MEF25%), and FEF50%-75% were found to be lower in comparison with the corresponding values recorded before the operation(P<0. 05).
Conclusion: Existing physical ventilation facilities are difficult to reduce the concentration of gaseous formaldehyde below the safety threshold. Exposure to ultra-high concentrations of gaseous formaldehyde caused a significant increase in subjective symptoms of medical students with secondary pulmonary function impairment.
Keywords: gaseous formaldehyde; physical ventilation; pulmonary function; subjective symptoms.