The rainy season UHI characteristics at several sites in Enugu urban were evaluated using paired measurement programme. The aim was to determine the characteristic of urban heat island in the city during rainy season periods. The study was undertaken in Enugu municipality in the months of June -July of 2006 and 2007. The results indicate that UHI at day and night during rainy season were very different. A downtown -centered heat island was observed both day and night. The day time variations were strongly correlated to the amount of tree shading while in the night, city climate was highly correlated to sky-view factors and thermal properties in the city. Maximum UHI was about 32c during the day and hour-to-hour difference was observed at night around (1800hrs to 2300hrs). UHI over Enugu have been analyzed and results reveal some spatial and temporal characteristics. The UHI has been found to occur throughout the day and night during rainy season. Its structure was observed to be greatly influenced by weather, city, metabolism, anthropogenic activities and local geographic features, land-use, land-cover as well as vegetation and population.

The Study examined the air pollution tolerance indices (APTI) of five plant species around Enugu urban area. Four physiological and biological parameters including leaf relative water content (RWC), ascorbic acid (AA) content, total leaf chlorophyll (TCh), and leaf extract pH were used to develop an APTI. The vegetation monitoring in terms of its APTI acts as a 'Bioindicator' of air pollution and can be incorporated into assessment studies for selecting trees for urban heat island (UHI) mitigation strategy. The result of the APTI showed order of tolerance as Anacarduim occidentale (22.20), Pinus spp (22.35), Catalpa burgei (22.57), Mangifera indica (23.37), and Psiduim guajava (24.15). A comparative analysis was also done between the shedding ability of these trees and their APTI. The result showed that the best tree that provides both shed and high air pollution tolerance appeared in that order: Psiduim guajava, Magifera indica, Catalpa burgei, Pinus spp and Anacarduim occidentale. The results of such studies are therefore handy for future planning, and as well provide tolerant species for landscape and urban heat island mitigation.

The study evaluated