Zareie - Chemical and Petroleum Engineering Department Shiraz University Shiraz-Iran
Fathi Kaljahi - Chemical and Petroleum Engineering Department Shiraz University Shiraz-Iran
Taheri - Chemical and Petroleum Engineering Department Shiraz University Shiraz-Iran
Hadad - Nuclear Engineering Department Shiraz University Shiraz-Iran

Carbon monoxide (CO) and oxides of nitrogen (NOx) produced from internal combustion engines would be accumulated to harmful levels in vehicular tunnels if the design and operation of ventilation system are unsatisfactory. This paper presents the results of environmental impact study of vehicle exhausts at the Zand tunnel located about center of Shiraz. Air pollution monitoring was carried out during 2006 and 2007. The pollutants include carbon monoxide (CO), sulfur dioxide (SO2) and nitrogen oxides (NOX) in 15 min. period averages. The tunnel is a two way road with 2 lanes on each side and is a major connection in east west commutation in centre of Shiraz. The analysis of measurements inside the tunnel showed that the CO concentrations, as well as other pollutants, have 2 major peaks located approximately 100 and 550 meters from the west entrance. During the monitoring period high levels of pollutants were observed. The analysis shows that poor ventilation, tunnel’s interior structure and traffic jams are the major sources of high level air pollution.

Air pollutants; Tunnel; Carbon monoxide