We measured and analyzed 9 parameters such as total dust, sulfur dioxide, carbon monoxide, nitrogen dioxide and lead in the air together with climatic conditions and traffic volumes at 10 major highway tollgates.

The results obtained were as follows:

1. The concentrations of air pollutants at inside and outside of toll booth were 0.7824 and 1.5460 mg/m3 for total dust, 0.034 and 0.094 ppm for sulfur dioxide, 2.2 and 4.3 ppm for carbon monoxide, 0.031 and 0.068 ppm for nitrogen dioxide, 0.0018 and 0.0027 mg/m3 for lead, respectiveively.

2. All air pollutants showed significant association each other except lead and nitrogen dioxide.

3. No relation was observed between air pollutants and traffic volume.

4. Generally speaking, climatic conditions showed no effect on the value of air pollutants both at inside and outside of toll booth. The exceptions were humidity that was related with carbon monoixide outside and air current that was related with lead outside.