Estimation of CO exposure of road construction workers in tunnel.

Carbon monoxide (CO) level in three different tunnels in Boston area have been measured during rush hour periods, and expected CO exposure of construction workers who possibly work there was also estimated. CO levels in these tunnels have been measured at outside of a car running through the tunnels. The data collected in this study include vehicle speed, length of tunnels and traffic volume. In addition, structure of each tunnel was investigated. These data were used to estimate relationship between CO level and the distance of sampling points from entrance/exit of each tunnel. CO concentration in each tunnel was distributed in the range of 5 ppm-42 ppm, and linear relationship between CO concentration and distance from entrance/exit has been observed. This study had been held from April 1989 to May 1989 in Boston, MA, USA.