The lungs are exposed to PM2.5 via inhalation; PM2.5 then settles in the alveoli and circulates via the blood system, causing chronic obstructive pulmonary disease and cardiovascular issues. PM2.5 triggers the formation of superoxide anions and provide signals for the formation of superoxide dismutase. Workers at ready-mix concrete factories had long-term exposure to high doses of PM2.5. This study investigates the effects of PM2.5 on the blood SOD concentration of workers.This cross-sectional study involved 53 subjects chosen with random sampling and interviewed to obtain individual characteristic data. PM2.5 value was measured by gravimetric analysis using High Volume Air Sampler and EPAM-5000. The SOD value was tested with the RanSOD-Kit and read using RX-Monza. Data were analyzed with chi-square and multiple logistic regression.It was determined that the workers exposed to PM2.5 ³65 mg/m3 had a 10x higher risk of obtaining a SOD concentration of <84.40 U/mL than the workers exposed to PM2.5 <65 mg/m3.There is a significant relationship between PM2.5 exposure and SOD concentration. Working status and length of employment were identified as contributing variables (p-value 0.029; OR 10.165; CI 1.276–90.994). This study suggests that PM2.5 exposure leads to a decrease in SOD concentration. It is necessary to take preventive measures for workers. © 2019, Indian Journal of Public Health Research and Development. All rights reserved.