Air pollution in the urban area is a major concern globally, which causes generally by natural or anthropogenic effects. Increased traffic activities cause an increase in the amount of exhaust harmful gases such as CO2 (carbon dioxide), HC (hydrocarbons), and NO (nitrogen oxides) release to the environment; which are responsible for both increases and decreases in rates of photosynthesis, stomatal conductance, responsible for vegetation injury, which lead to decrease crop yield. Considering these important aspects, the present study was undertaken to determine the effects of air pollution caused by exhaust emissions of harmful gases on plants. For this purpose, stoma intensities, proline, total soluble sugar and amino acid contents and some heavy metal accumulations were recorded on Eucalyptus camuldensis which were located in different distances (i.e., 0, 10, 30, 50, 70, 90 and 110 meters) from the highway of two cities namely Adana and Tarsus of Turkey. Data on opened stoma intensities, proline content and heavy metal concentrations (such as Zn, Fe, Pb, and Cd) were shown a statistically meaningful decreasing trend when distances from the highway were increased. It was also seen as meaningful increasing on total soluble sugar and amino acid contents. It was also recorded the concentration of soluble sugar and proline in polluted leaves of Eucalyptus camuldensis were significantly increased as compared to plants grown under control condition, indicating that the activation of protective mechanism in plants under air pollution, and the plant may act physiological adjustments to compensate for that air pollution stress.