PURPOSES : The objective of this study is to determine the characteristics of nitrogen oxide (NOx) concentration in an exclusive median bus lane station. The hourly variations of NOx concentration and the effect of traffic volume on NOx concentration were analyzed using NOx measurement data and the number of vehicles at the station.
METHODS : Data were collected using the chemiluminescence method for NOx concentration. Atmospheric information and traffic volume of buses were collected from the Korea Meteorological Administration and Bus Information System, respectively.
RESULTS : As a result, the NO2 concentration in the test section was found to have a strong correlation with those in the atmospheric measurement station located near the test-bed. In addition, the average NOx concentrations in the test section were significantly higher than those of the other monitoring stations due to bus emissions. The average NOx concentration in the exit section was higher than that in the entry section owing to the vehicle’s frequent stops and fuel consumption due to acceleration. During the measurement period, the average NOx concentration was measured as approximately 33 % higher in the exit section than in the entry section. In addition, the NOx concentration at the bus station was found to increase as the bus dwell time increased, rather than the number of bus passages.
CONCLUSIONS : This study provides clear characteristics of the NOx correlations with traffic information in an exclusive median bus lane station. It was shown that the NOx concentration at the bus station increased as the number of passes and bus dwell time increased. According to the coefficient of determination, the dwell time is more closely correlated to the NOx concentration at the bus station than the number of bus passes, indicating that it is a better parameter for predicting NOx concentration at bus stations.

ABSTRACT
1. Introductuon
    1.1. Research Background
    1.2. Research Objectives
2. Site Descriptions and Measurement Methods
3. Results and Discussion
    3.1. Comparison of NO2 Concentration betweenTest Section and Atmospheric MeasurementStations
    3.2. Comparison of NOx Concentration betweenBus Entry and Exit Sections
    3.3. Effect of Bus Traffic Characteristics on theNOx Concentration
    3.4. Relationship between Bus Dwell Time andNOx Concentration
4. Conclusions
REFERENCES

• Lee Jong Won(Korea Institute of Civil Engineering and Building Technology) | 이종원
• Kim Moonkyung(Korea Institute of Civil Engineering and Building Technology) | 김문경
• Park Ki Soo(Korea Institute of Civil Engineering and Building Technology) | 박기수
• Lee Sang Hyuk(Korea Institute of Civil Engineering and Building Technology) | 이상혁
• Park Hee Mun(Korea Institute of Civil Engineering and Building Technology) | 박희문 Corresponding Author