Abstract: This study was conducted to obtain information on the alteration of some ornamental landscape plants antioxidants (ascorbic acid) and pigments (chlorophyll and carotenoid), caused by urban air pollution. Analysis of leaf pigments (chlorophyll and carotenoids) performed by spectrophotometric method and ascorbic acid content was analysed by DCPIP titration methods. Data were analyzed using analysis of variance. Levels of chlorophyll a, chlorophyll b and total chlorophyll of plants located in the motor vehicle emission pollution area, reduced by 40% compared with plants grown in a pollution free area. Carotenoid levels also decreased by 3%. There are no statistically significant changes in the levels of leaves ascorbic acid of plants growing in polluted area. This parameter can not be used as indicators of air pollution. The design of air quality monitoring sensor system can be integrated with changes in levels of leaf pigments: chlorophyll a, chlorophyll b and total chlorophyll.