도시 자동차도로 터널 내부의 대기오염도 공간분포 특징

Abstract

Air pollution levels of gases and aerosol particles inside the Jeongneung and Hongjimun tunnels of the Naebu express way in Seoul were investigated through on-road measurement using a mobile emission laboratory (MEL) on February 8, 2011. The concentrations of NOx, CO2, number concentration of particles ranging 21-560 ㎚, and surface area of particles deposited on a human lung almost linearly increased with increasing distance from the tunnel entrance, and decreased rapidly before the tunnel exit. This trend was observed regardless of tunnel length and driving directions, which thought to be caused by semi-transverse ventilation facilities of the tunnels. The concentration increments per 1-m distance for NOx, CO2, deposited particle surface area, and number of particles ranging 21-560 ㎚ were 0.61~0.80 ppb, 0.16~0.21 ppm, 0.20~0.29μ㎡/㎤, and 117~192 particles/㎤, respectively. Average pollution levels inside the two tunnels for CO2, deposited particle surface area, and number of particles >5.6 ㎚ ranged 681~748 ppm, 246~381μ㎡/㎤, and 2.4~6.7×105 particles/㎤, respectively. In case of NOx, the maximum concentration exceeded 1 ppm. These pollution levels inside the tunnels are much higher than those at urban background sites. This result can be utilized as basic data to evaluate the effectiveness of present ventilation system for reducing the pollution level caused by vehicles inside the tunnels.