Assessing the Health Risks of Sawmill Workers Associated with Particulate Matter Toxicity: A Case Study of Benin City, Nigeria

Background: Sawmills are essential to the timber industry, but they pose significant occupational health risks, primarily from airborne particulate matter (PM) pollution. Objectives: This study aims to assess the toxicity of PM and its link to reported respiratory problems among sawmill workers in Benin City, Nigeria. Methods: Quantitative measurements of PM2.5 and PM10 were conducted in 10 randomly selected sawmills using a calibrated BR-SMART-126S handheld air quality detector. The toxicity potential of the measured PM concentrations was determined. A cross-sectional study involving 200 participants utilised a modified British Medical Research Council questionnaire to assess respiratory symptoms. A binomial logistic regression model was employed to identify factors associated with these symptoms. Data were analysed using SPSS v21.0 with descriptive statistics, chi-square tests, and bivariate logistic regression; significance was set at p < 0.05. Results were presented as medians, box plots, frequencies, percentages, cORs, and 95% CIs. Results: The particulate matter exposure levels among sawmill workers ranged from 32 – 36 µg/m3 (PM2.5) and 40 – 44 µg/m3 (PM10). The level of PM2.5 exceeded the limit of 15 µg/m3 set by the WHO. The toxicity potential (TP) values of PM2.5 were greater than 1 at all the sampling sites. The prevalence rates of reported respiratory symptoms among workers were 31%, 26%, 29%, 26% and 23% for shortness of breath, wheezing, cough, chest pain, and sore throat, respectively. Work experience (cOR = 5.96; 95% CI: 1.243 – 28.629), daily duration of exposure (cOR = 3.51; 1.737 – 7.130), open burning of wood waste (cOR = 20.68; CI = 3.537 – 120.96) and use of diesel-powered generators (cOR = 16.44; CI = 5.660 – 47.752) in the sawmills were determining factors for reported respiratory symptoms among workers. Conclusion: The study found a high prevalence of respiratory health issues among workers. The key factors contributing to these problems include: longer employment, prolonged daily exposure, open burning of sawmill wastes and the use of diesel-powered generators: These generators release harmful emissions which increase the likelihood of respiratory symptoms.