Cross-market evaluation of airborne pollutant exposure and COPD biomarkers in southeastern Nigeria: A toxicological perspective

• Air pollutants (CO, NH₃, and O₃) exceeded WHO limits in chemical markets, especially in Ogbete Market. • Elevated respiratory biomarkers (PGE₂, 8-Isoprostane, NO₂, RS-NO) indicate inflammation and oxidative stress in storekeepers. • Ogbete Market showed higher pollutant exposure and health risks compared to Ogbo-ogwu Market. • Real-time air quality monitoring combined with biomarker analysis offers a robust occupational health assessment method. • Study calls for improved ventilation and regular health checks to reduce pollutant-related health effects. This study explored the effects of air pollution on chemical storekeepers' health in Onitsha and Enugu, southeastern Nigeria, by examining the concentrations of carbon monoxide (CO), ammonia (NH₃), and ozone (O₃), as well as evaluating biomarkers for chronic obstructive pulmonary disease (COPD) in exhaled breath condensate (EBC). A total of 104 storekeepers making up of 52 storekeepers from 12 different chemical stores and 1 clothing store from each of the two markets participated in this study. Conducted during the wet season, the study utilized an Aeroqual Series 300 for air quality measurements and R-tubes for EBC collection, with biomarkers analyzed using ELISA test kits. Results indicated elevated pollutant concentrations in both markets, with CO, NH₃, and O₃ concentrations frequently approaching or exceeding WHO guidelines, especially in Ogbete Market. Corresponding increases in biomarkers—Prostaglandin E2 (PGE2), 8-Isoprostane, Nitrite (NO₂), and Nitrosothiols (RS-NO)—reflect significant respiratory inflammation and oxidative stress. Ogbete Market exhibited higher pollutant levels and biomarker concentrations compared to Ogbo-ogwu Market, highlighting a more severe environmental and health risk. The findings underscore the urgent need for improved ventilation in chemical stores and regular health monitoring for storekeepers. This research contributes novel insights by integrating air quality data with health biomarkers in a tropical context, providing a comprehensive assessment of occupational health risks. The results advocate for targeted interventions, including enhanced air quality management and preventive health measures, to mitigate the adverse effects of pollutant exposure on chemical storekeepers. Future research should focus on long-term health impacts and the efficacy of intervention strategies to further safeguard occupational health in similar environments.