For several decades, Nigerian cities have been experiencing a decline in their biodiversity resulting from rapid land use land cover (LULC) changes. Anticipating short/long-term consequences, this study hypothesised the effects of LULC variables in Akure, a developing tropical rainforest city in south-west Nigeria. A differentiated trend of urban LULC was determined over a period covering 1999–2019. The study showed the net change for bare land, built-up area, cultivated land, forest cover and grassland over the two decades to be −292.68 km2, +325.79 km2, +88.65 km2, +8.62 km2 and −131.38 km2, respectively. With a projected population increase of about 46.85%, the study identified that the built-up land cover increased from 1.98% to 48.61%. The change detection analysis revealed an upsurge in built area class. The expansion indicated a significant inverse correlation with the bare land class (50.97% to 8.66%) and grassland class (36.33% to 17.94%) over the study period. The study observed that the land consumption rate (in hectares) steadily increased by 0.00505, 0.00362 and 0.0687, in the year 1999, 2009 and 2019, respectively. This rate of increase is higher than studies conducted in more populated cities. The Cellular Automata (CA) Markovian analysis predicted a 37.92% growth of the study area will be the built-up area in the next two decades (2039). The 20-year prediction for Akure built-up area is within range when compared to CA Markov prediction for other cities across the globe. The findings of this study will guide future planning for rational LULC evaluation.

As a step towards remediation of sulphur contaminants, this study used a Crowcon Gasman (gas detection instrument) to collect and analyze Sulphuric gas samples from densely populated areas of urban Zaria. The results showed varying concentrations of Sulphur Dioxide (SO 2 ) and Hydrogen Sulphide (H 2 S). The high concentrations of these pollutants detected can be attributed to increased population growth, increased production of gaseous wastes and increased number of vehicular movement. The results indicate also that the concentrations of pollutant sulphur component SO 2 measured at all sampling points, with exception of the control site were hazardous while that of H 2 S were within safe limit set by FEPA and ACGIH respectively. Statistical tests were performed which established significant variation/relationship between detected pollutants and traffic volume. Findings from this study imply that vehicular emission within urban Zaria is not within the safe limit which further reveals that transport-related pollution in Zaria urban area can be potentially hazardous to health.

While it is anticipated that there would be some similarities amongst spectral Vegetation Indices (VIs) because the majority of the indices use the red and NIR bands, it is also expected that there would be some variances. The NDVI, derived earlier by Rouse (1973), and is the commonly used VI, there have meagre understanding of the relationship between the NDVI and another VIs. Similarly, investigations on the correlation between LST and other VIs (other than NDVI) in both dry and raining seasons have not been adequately explored. This motivated the study to determine the seasonal correlation of some spectral VIs against the NDVI and LST over the forest reserve area. The study investigated two categories of VIs: slope-based and distance-based. It derived spectral VIs from Landsat 8 images for dry (January) and raining (August) seasons; and estimated LST from MODIS. The findings showed that the ARVI, GNDVI and TVI not only showed resemblance in appearance with the NDVI in both seasons, but also had a high coefficient of correlation: ARVI = 0.973, 0.964; GNDVI = 0.919, 0.879; TVI = 0.779, 0.716. Based on this finding, the ARVI, GNDVI and TVI can be used to supplant the NDVI for biomass related studies in the study area. The study further revealed that the LST-VIs relationship was negative for both dry and rainy seasons, except for the distance-based VIs (DVI, SAVI, MSAVI) that specifically had a positive correlation with the LST. The LST was strongly correlated with the GNDVI, TVI, NDVI, ARVI (0.664 ? r ? 0.598). However, the strength of the correlation for the LST-VIs in the raining season was very weak (0.003 ? r ? 0.245). The study concluded that the correlation of the LST versus the ARVI, GNDVI, NDVI, and TVI can be used for climate related studies.

As a step towards remediation of sulphur contaminants, this study used a Crowcon Gasman (gas detection instrument) to collect and analyze Sulphuric gas samples from densely populated areas of urban Zaria. The results showed varying concentrations of Sulphur Dioxide (SO2) and Hydrogen Sulphide (H2S). The high concentrations of these pollutants detected can be attributed to increased population growth, increased production of gaseous wastes and increased number of vehicular movement. The results indicate also that the concentrations of pollutant sulphur component SO2 measured at all sampling points, with exception of the control site were hazardous while that of H2S were within safe limit set by FEPA and ACGIH respectively. Statistical tests were performed which established significant variation/relationship between detected pollutants and traffic volume. Findings from this study imply that vehicular emission within urban Zaria is not within the safe limit which further reveals that transport-related pollution in Zaria urban area can be potentially hazardous to health.

As a step towards remediation of sulphur contaminants, this study used a Crowcon Gasman (gas detection instrument) to collect and analyze Sulphuric gas samples from densely populated areas of urban Zaria. The results showed varying concentrations of Sulphur Dioxide (SO 2 ) and Hydrogen Sulphide (H 2 S). The high concentrations of these pollutants detected can be attributed to increased population growth, increased production of gaseous wastes and increased number of vehicular movement. The results indicate also that the concentrations of pollutant sulphur component SO 2 measured at all sampling points, with exception of the control site were hazardous while that of H 2 S were within safe limit set by FEPA and ACGIH respectively. Statistical tests were performed which established significant variation/relationship between detected pollutants and traffic volume. Findings from this study imply that vehicular emission within urban Zaria is not within the safe limit which further reveals that transport-related pollution in Zaria urban area can be potentially hazardous to health.