It was conducted to compare the availabilities of parameters for evaluating the sink capacity of the broad leaves trees such as Acer saccharium, Ailanthus altissima, Ginkgo biloba, Platanus occidentalis and Salix pseudolasiogyne. These trees, repoted as resistant species to air pollutants, were exposed to $SO_2$, $NO_2$ and CO within a phytotron at $25^{circ}C$ with 70% of relative humidity. Since the amount of ad- or absorbed gas does not always agree with the amount of accumlated pollutants in leaves and with the stomatal density, it is assumed that the amount of ad- or absorbed gas is the most basal index to evaluate the sink capacity of trees. The stomatal diffusive resistance, which has a good agreement with the amount of ad- or absorbed gas, is also available for evaluating the sink capacity of broad leaves trees.