The objectives of this resarche were to find and describe the minimum ozone exposure needed to cause visible injury on bioindicators, to make comparaison between concentration-based ozone exposure indices and ozone uptake based exposure, to develop a new uptake-based model of ozone into bean and wheat plants and suggest and define a new short-term critical level for tropospheric ozone effects. Another objective was to describe and analyse factors influencing the ozone sensitivity of the local tested plants. We use genotypes of bean (Phaseolus vulgaris L.) and (Wheat L.) with various degrees of sensitivity to investigate the impacts of ozone on the morphology and development of the plants. We use ozone-induced foliar injury index and we measure the percentage of leaves necrosis to quantify the ozone stress on the plants. We expected that the local plants used in the experiment would have the same responses as the ozone-sensitive genotypes. However, the results show that the soft wheat variety shows a remarkable sensitivity similar as the ozone-sensitive genotype suffering higher ozone-induced leaf damage. But the resistant or local genotype is postulated that the high ozone sensitivity of sensitive genotypes causes leaf damage and therefore results in higher marked-sensitivity responses.