To find out the extent of air pollution in Taejon city, we investigated the concents of heavy metals in barks of trees in principal roadside, the outer block of a roadside and Pomunsan Park. Among the road-side trees in these areas, Platanus orientalis, Ginkgo biloba and Liriodendron tulipifera have been chosen. And we analyzed the relationship between the content of heavy metal of the barks and the traffic volume expressed by cars passing through for an hour. The range of contents of the lead in barks of the trees in the roadside and Pomunsan Park were respectively 2-1109 ppm and 5-11 ppm. Generally the contents of lead of barks of the trees in roadside was much higher than that in Pomunsan Park. And there has been positive correlation between the traf-fic volume and the content of lead in the barks. The more cars passing through for an hour, the higher the maximum in contents of lead in the barks of roadside trees. By the way the contents of cadmium in barks of the roadside trees was slightly higher than that in Pomunsan Park and was little variable.