This study collected and re-analysed the articles of exposure assessment for the indoor environment of offices in journals related environment in Korea since 1990, and estimated the unit health risk on indoor environment. The objective of this study was to offer scientific data for decision-making of policy for improvement and management of indoor air quality on office in Korea. The pooled concentration for the critical air pollutants in the office was estimated 114 ± 84 ㎍/m3 for respirable particle, 2 ± 1.6 ppm for carbon monoxide and 1,008±983 ppm for carbon dioxide, respectively. And the pooled concentration for the volatile organic compounds was estimated 11.1±13.1 ㎍/m3 for benzene, 65,8±79.8 ㎍/m3 for toluene, 7.7±9.3 ㎍/m3 for ethylbenzene, 23.1 ± 25.6 ㎍/m3 for m-p-xylene, 5.5 ± 5.2 ㎍/m3 for styrene and 14.6 ± 17.9 ㎍/m3 for o-xylene, respectively. The result of the risk assessment for the critical pollutants by Monte Carlo analysis showed that the probability of the safety factor exceeded 1 was 36.83% for respirable particle and 99.12% for carbon dioxide, respectively. The unit cancer risk for men and women by inhalation of benzene was 8.9×10-6 and 6.1×10-6, respectively. And hazard indexes for toluene, ethylbenzene, m-p-xylene, styrene, and o-xylene were less than 1.