Occupational Airborne Pollutant Exposure and Hematological Outcomes in Workplace Settings: A Systematic Review

Occupational exposure to airborne pollutants poses a significant risk to hematological health. This systematic review aims to evaluate the associations between workplace airborne pollutants and key blood parameters, as well as the modifying roles of age and body mass index (BMI) among adult industrial workers. Following PRISMA guidelines, a comprehensive search across Scopus, PubMed, Web of Science, Embase, and Medline identified studies published over the last five decades. The search strategy incorporated terms related to occupational air pollution and airborne pollutants, including particulate matter (PM), volatile organic compounds (VOCs), and heavy metals (HMs). Studies evaluating occupational exposures and reporting hematological outcomes-hemoglobin concentration, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and anemia prevalence-were included. Methodological quality was assessed using study design-specific JBI critical appraisal checklists. Out of 1855 retrieved records, 55 studies (predominantly from developing and industrializing countries) met the eligibility criteria. Findings reveal that workplace exposure to VOCs, HMs (e.g., lead), and PM is consistently associated with subclinical hematological alterations, characterized by lower hemoglobin levels and altered red blood cell indices (MCH and MCHC). Notably, despite high workplace pollutant concentrations, linear correlations between pollutant levels and hematological indices were often weak, indicating complex exposure-response dynamics. Analysis of modifying factors showed that higher BMI was positively associated with hemoglobin levels, potentially suggesting a protective buffering pattern, whereas age exhibited weak associations, likely reflecting a "healthy-worker effect" in exposed populations. The complexity of these findings underscores the necessity of moving beyond single-pollutant assessments toward evaluating mixed workplace exposures. Integrating routine hematological surveillance and nutritional screening into occupational health programs is crucial for mitigating workplace hematotoxicity.