Lung function status of workers exposed to wood dust in timber markets in Calabar, Nigeria.

The effect of chronic exposure to dust from local woods such as ebony, achi, and iroko on lung function of timber market workers in Calabar - Nigeria, was studied. Forced vital capacity (FVC), Forced Expiratory Volume in one second, (FEV1), Forced Expiratory Volume as a percentage of forced vital capacity (FEV1 %), and Peak Expiratory Flow Rate (PEFR) were measured in 221 workers (aged 20-25 years) exposed to wood dust to assess their lung function and compared with 200 age- and sex- matched control subjects who were not exposed to any known air pollutant. The concentration of respirable dust was significantly higher in the test (P<0.001) than in control site. The mean values of FVC, FEV1, FEV1% and PEFR of the timber workers were significantly lower (P<0.01) than in control subjects. Respiratory symptoms such as cough, chest pain and nasal irritation had higher prevalence in the test group than in the control group. Non-respiratory symptoms (skin and eye irritation) were prevalent in the test group but not found in the control group. Workers exposed to wood dust had restrictive pattern of ventilatory function impairment. The lung function indices of the timber workers decreased with their length of service. Chronic exposure to wood dust impairs lung function.