To estimate the impact of copying on the indoor air quality, and to investigate whether ozone emitted during such a process induces pathological oxidative stress and potential oxidative damage in the bodies of operators. Methods 67 copying operators (CO) and 67 healthy volunteers (HV) were enrolled in a random control study, in which levels of lipoperoxide (LPO) in plasma and erythrocytes, and levels of vitamin C (VC), vitamin E (VE) and b-carotene (b-CAR) in plasma as well as activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in erythrocytes were determined by spectrophotometric methods. Results Compared with the HV group, the average values of LPO in plasma and erythrocytes in the CO group were significantly increased (P<0.0001), while those of VC, VE and b-CAR in plasma as well as those of SOD, CAT and GPX in erythrocytes in the CO group were significantly decreased (P<0.0001). Pearson product-moment correlation analysis showed that with increase of ozone level in copying sites and duration of exposure to ozone, the values of LPO in plasma and erythrocytes in the bodies of operators were gradually increased,while those of VC, VE, b-CAR, SOD, CAT and GPX were decreased in the same manner. Odds ratio (OR) of risk of biochemical parameters reflecting potential oxidative damage of the copying operators ranged from 4.440 to 13.516, and 95 % CI of OR was from 2.113 to 34.061. Reliability coefficient () of the biochemical parameters used to reflect the potential oxidative damage of the operators was 0.8156, standardized item =0.9929, P<0.0001. Conclusion Findings in the present study suggest that there exist a series of free radical chain reactions and pathological oxidative stress induced by high dose ozone in the operators, thereby causing potential oxidative and lipoperoxidative damages in their bodies. To estimate the impact of copying on the indoor air quality, and to investigate whether ozone emitted during such a process induces pathological oxidative stress and potential oxidative damage in the bodies of operators. Methods 67 copying operators (CO) and 67 healthy volunteers (HV) were enrolled in a random control study, in which levels of lipoperoxide (LPO) in plasma and erythrocytes, and levels of vitamin C (VC), vitamin E (VE) and b-carotene of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX) in erythrocytes were determined by spectrophotometric methods. Results Compared with the HV group, the average values ​​of LPO in plasma and erythrocytes in the CO group were significantly increased <0.0001), while those of VC, VE and b-CAR in plasma as well as those of SOD, CAT and GPX in erythrocytes in the CO group were significantly decreased (P <0.0001). Pearson product-moment correlation analysis showed that with in crease of ozone level in copying sites and duration of exposure to ozone, the values ​​of LPO in plasma and erythrocytes in the bodies of operators were gradually increased, while those of VC, VE, b-CAR, SOD, CAT and GPX were decreased in Odds ratio (OR) of risk of biochemical parameters reflecting potential oxidative damage of the copying operators ranged from 4.440 to 13.516, and 95% CI of OR was from 2.113 to 34.061. Reliability coefficient () of the biochemical parameters used to reflect the potential oxidative damage of the operators was 0.8156, standardized item = 0.9929, P <0.0001. Conclusion Findings in the present study suggest that there exist a series of free radical chain reactions and pathological oxidative stress induced by high dose ozone in the operators, thereby causing potential oxidative and lipoperoxidative damages in their bodies.