Air pollution assessment was carried out using chlorophyll concentration reduction criterion of some higher plants leaves such as (Masquerade tree) Polyathia longifolia (Sonn.) Thwaites, (Mango) Mangifera indica Linn. (Guava) Psidium guajava Linn. and (Indian Almond) Terminalia catappa Linn. as the bio-indicator species. The study was carried out at three (3) different locations namely polluted area (Ring Road, Benin City), slightly polluted area (Ekosodin Gate) and unpolluted area (Professor’s Staff Quarters) inside University of Benin, Ugbowo Campus, Benin City, Edo State, Nigeria. Chlorophyll content of intact matured leaves of study plants were measured in situ using a hand-held digital chlorophyll content meter CCM 200 Plus. The study revealed that there were significant reduction (P < 0.05) of chlorophyll concentration at Ring Road area and Ekosodin Gate area when compared with plants at Professors’ Quarters. The percentage chlorophyll reduction at Ring Road and Ekosodin Gate in Polyathia longifolia, Mangifera indica, Psidium guajava, and Terminalia catappa leaves in relation to the Professors’ Quarters were 46.63 %, 45.08 %, 45.03 %, 31.79 % and 23.85 %, 25.46 %, 23.94 %, 25.71 % respectively. These results confirmed that Ring Road is highly polluted than the other study areas. This study revealed that changes occurred in chlorophyll content of plants due to air pollution and that plant act as a sink for air pollutant which eteriorates their photosynthetic pigments which invariably leads to reduction in plant productivity. This study, therefore shows that plants chlorophyll content can be used as bio-indicator of pollution.