Occupational particulate burden and airway oxidative–inflammatory responses in chemical retail environments

Abstract Purpose This study investigated particulate concentrations and respiratory biomarkers among chemical storekeepers in Ogbete Market, Enugu Nigeria to evaluate early indicators of airway injury relevant to occupational toxicology. Methods Twenty four chemical storekeepers from 6 stores (4 per store) and a control group of 4 clothing storekeepers (4 from 1 store) participated in both wet and dry seasons. The 28 Participants were sampled once a month for three months in each season. Indoor particulates (PM₁, PM₂.₅, PM₄, PM₇, PM₁₀, and TSP) were measured during wet and dry seasons using an Aerocet 531 analyzer. The 7 stores were sampled once a month for three months in each season. Exhaled breath condensate (EBC) was collected with the R-Tube, and biomarkers of Chronic Obstructive Pulmonary Disease (COPD)—pH, hydrogen peroxide (H₂O₂), thiobarbituric acid-reactive substances (TBARS), glutathione (GSH), and leukotriene B₄ (LTB₄), were quantified using ELISA. Data were analyzed using SPSS version 25. Results Particulate concentrations were higher in chemical stores than in controls across all size fractions and exceeded OSHA limits and WHO standards (PM2.5 and PM10) in several locations, particularly during the dry season (e.g., PM₂.₅: 6.4 ± 1.1 mg/m³ in Store 1 vs. 1.4 ± 0.3 mg/m³ control; TSP: 24.1 ± 3.1 mg/m³ in Store 1 vs. 3.5 ± 0.8 mg/m³ control). Biomarker profiles showed lower EBC pH, elevated H₂O₂ and TBARS, reduced GSH, and higher LTB₄ among storekeepers, with stronger differences during the dry season (e.g., LTB₄: 94.0 ± 12.5 pg/mL in Store 1 vs. 24.0 ± 6.0 pg/mL control). ANOVA indicated significant group differences (p ≤ 0.05), with consistent seasonal effects. Conclusion Overall, the findings suggest that routine occupational activities in these stores are associated with increased particulate exposure and biochemical evidence of oxidative stress and airway inflammation. While causality and long-term outcomes cannot be inferred, the results highlight the need for improved exposure controls, worker education, and further longitudinal research.