**3. Methods**

### *3.1. Micro-Level Emission Estimation Method Using Individual Vehicle Trajectory Data*

### 3.1.1. Micro-Level Emission Factor

The MOVES's micro-level emission estimation methodology is applied to calculating emissions with trajectories of individual vehicles collected from vehicle navigation, odometer (i.e., DTG), and mobile devices. The MOVES database stores the basic emission factors for each pollutant at OpMode by each vehicle type, which is subdivided by fuel use, size, year of manufacture, and vehicle age. MOVES provides the result of calculating the emissions according to various conditions, such as the vehicle type composition ratio, fuel compound characteristics, and temperature and humidity on the road section.

In this study, the base emission rates for each vehicle type from the MOVES database are applied to calculate the basic emission factors at the OpModes of passenger cars, trucks, and buses, as shown in Appendixes A–C. In order to make these tables, the ratios of each subdivided vehicle type (size, fuel, vehicle age) of the target year 2017 in Bucheon, Gyeonggi-do, which is an analysis target area collected from the Korea vehicle registration information, are used as weighted values. CO, NOx, PM10, PM2.5, and CO2 are selected as the pollutants to be estimated, and the unit of the emission factors is g/sec. The emissions are calculated in this study without considering the adjustment for climatic conditions.
