This study aimed to review the accuracy of the unit method estimating used to reduce particulate matter when planning city and architecture, and then to present improvement directions. Method: In order to achieve the purpose, particulate matter reduction techniques were listed through literature review. In addition, input and initial data for CFD(Computational Fluid Dynamics) simulation were obtained through (Korea Meteorological Administration’s) AWS(Automation Weather Station) data and field measurement. And the amount of particulate matter reduction by the particulate matter reduction techniques was calculated using the unit method estimating on the 500m × 500m area of the 1st Phase project area in Godeok International District. Next, CFD simulation was conducted to analyze the path through which particulate matter spreads and reduction amount through three types particulate matter reduction techniques. The unit method estimating and CFD simulation results were compared. Finally, assuming that the difference was caused by the wind, the CFD simulation was conducted by increasing the wind speed to 2m/s, 5m/s, and 10m/s. Result: It was found that the amount of particulate matter reduction by CFD simulation was less than the result of calculation by the unit method estimating. As a result of CFD simulation performed to explain this, it was found that the higher the wind speed, the lower the amount of particulate matter reduction. Through this, it was judged that the difference was observed because the unit method estimating did not calculate considering the wind. Through this result, it is thought that the speed of the wind and the direction of the wind should be considered in order to upgrade the unit method estimating in the future. The results of this study contributed to setting the direction of the unit method estimating advancement for use for particulate matter free urban and architectural design.