This study apprises the local and global implication of ambient air quality index of Kaduna Metropolis, Nigeria. With the point of investigating the spatial and transient dissemination of the Air Quality Index (AQI) of Carbon monoxide (CO), Sulfur dioxide (SO 2), and Particulate Matter (PM 10) and their suggestions on human wellbeing, in view of neighborhood and global measures. Data were collected during the raining season and dry harmattan weather. From traffic, Industrial, commercial and residential areas, utilizing validated portable pollutant monitors (MSA Altair 5x Gas Detector a) to collect data on the concentration of air pollutants (CO and SO 2) and (CW-HAT200 Particulate Counter) for the concentration of particulate matters (PM 10). Equal allocation stratify sampling and purposive sampling were utilized for the selection of sample points. The data were analyzed in line with USEPA Air Quality Index calculation approach and using descriptive statistics. The findings reveal that the AQI of Kaduna Metropolis ranges from good to hazardous, CO has 57.57% and 24.24% of the sample sites AQI ranging from unhealthy to hazardous based on WHO/USEPA and NESREA standards respectively. Equally SO 2 has about 91%, 34.23%, 42.42% of the sites AQI ranging from unhealthy to hazardous base on WHO, USEPA and NESREA standards respectively. PM 10 has 75.76% and 18.18 of the sites AQI as hazardous base on WHO and USEPA standards, whereas none of the sites AQI is hazardous base on the NESREA standard. Further analysis shows that the northern part of the metropolis has more sites with unhealth AQI than the southern part of the metropolis. Also, the traffic land use has more of its sites AQI ranging from unhealthy to Sensitive group to hazardous. In conclusion this study provides empirical data on the AQI of Kaduna metropolis which ranges from good to hazardous. Thus, the need for the enforcement agencies to strictly enforce the guide lines regulating ambient pollution in the study area.

This study analyzes the varying spatial relationship between air pollutants [Carbon monoxide (CO), Sulphur dioxide (SO2), Carbon dioxide (CO2) and Particulate Matter (PM2.5 and PM10)] in Kaduna metropolis. This was aimed at having more insight into be characteristics of air pollutants in the study area, which was geared towards efficient environmental management of the city. Validated portable pollutant monitors (MSA Altair 5x Gas Detectora, CO2 meter Model AZ-0002-DL and CW-HAT200 Particulate Counter) were utilized for data collection, on the concentration of air pollutants CO and SO2; CO2 and particulate matters (PM2.5 and PM10) respectively. Pearson correlation and Geographical Weighed Regression (GWR) were used for data analysis, whereas, maps and tables were utilized for data presentation. The findings revealed that a non - perfect positive linear relationship exists between the air pollutants. The GWR model revealed that the distribution of the local R2 values vary spatially across Kaduna Metropolis, indicating that there is a spatially varying relationship between the air pollutants. Higher R2 values were mostly in the central and southern part of the metropolis except for PM2.5 and PM10 in the Northern part of the metropolis. The finding further reveals that CO has the strongest association with SO2, SO2 has the strongest association with PM2.5 and PM10, CO2 with SO2, PM10 has the highest association with PM2.5, likewise PM2.5 with PM10. The use of GWR to establish the existence of locally varying relationship between the air pollutants was successful. Hence, this study recommends the use of GWR to model air pollutants in cities with limited monitoring capability.

A laboratory testing programme was carried out to investigate the influence of Locust Bean Waste Ash (LBWA) on cation exchange and plasticity characteristics of Ordinary Portland Cement (OPC) modified lateritic soil. Preliminary tests were carried out on the natural soil to determine its properties. Other tests were carried out on soil-cement mixtures with up to 4% OPC admixed with 8% locust bean waste ash content by dry weight. Improvement in the plasticity characteristics of the soil was reflected in the decrease of liquid limit, increase in plastic limit and decrease in plasticity index with increased cement and locust bean waste ash content. The results using analysis of variance showed statistical significance. These results showed that modification with cement and locust bean waste ash blend significantly improved the plasticity characteristics through cation exchange of the lateritic soil.