This study describes the environmental impact of the material production, transportation, and construction phases from the construction site perspective. CO₂ emissions for each process were determined using the Korea Life Cycle Inventory Database (LCI DB) in the material production phase, and the actual amounts of oil consumption for transportation equipment were identified in the material transportation phase. Generally, the oil and electric energy consumed during the construction was evaluated by direct monitoring. Through the construction period and cost according to work type, a correlation with CO₂ emissions was also investigated. In addition, CO₂ emissions were examined through the system capacity and gross floor area for each work type. The calculations have shown that CO₂ emissions from the material production phase constitute 93.4% of the total CO₂ emissions. In addition, CO₂ emissions from the material transportation and on-site construction account for 2.4% and 4.2% of the total CO₂ emissions, respectively. This paper concludes that it is important to select appropriate input materials and resources for the reduction of CO₂ emissions. Furthermore, the amount of CO₂ emissions arising from the construction site was reduced by finding and practicing measures to reduce CO₂ emissions for each process.