The level of Indoor Air Quality (IAQ) has become a big topic of research, and improving it using passive ventilation methods is imperative due to the cost saving potentials. Designing lecture buildings to use less energy or Zero Energy (ZE) has become more important, and analysing buildings before construction can save money in design changes. This research analyses the performance (thermal comfort [TC]) of a lecture room, investigate the use of passive ventilation methods and determine the energy-saving potential of the proposed passive ventilation method using Computational Fluid Dynamics (CFD). Results obtained showed that air change per hour at a wind velocity of 0.05 m/s was 3.10, which was below standards. Therefore, the lecture hall needs external passive ventilation systems (Solar Chimney [SC]) for improved indoor air quality at minimum cost. Also, it was observed that the proposed passive ventilation (SC) system with the size between 1 and 100 m 3 , made an improvement upon the natural ventilation in the room. There was a 66.69% increase after 10 years in the saving of energy and cost using Solar Chimney as compared to Fans, which depicts that truly energy and cost were saved using passive ventilation systems rather than mechanical ventilation systems.

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This study correlates the different opinions held by Nigerian construction industry stakeholders who participated in the survey on the types of material wastes that are generated from the activities of procuring building projects across the states in southwest region of Nigeria. This was achieved through the random distribution of 261 questionnaires to build environment professionals recruited in the study. The results from 261 respondents was analysed using SPSS 26.0 and presented using tables, figure, ranking and percentile. The study found that the wastes from building construction activities are primarily physical in nature and perceived to be prominent at the post-construction and construction phases of a building project, however, it is seen to occur across the life cycle stages of a building project in varying proportions that adds up to become significant and critical. Additionally, the study found that paper was the most (31.7% and 39.5%) common form of wastes generated at the pre-design and design stages of a building project., while at the pre-construction stage, cardboard and other package materials (35.1%) were the most common form of waste generated, Also, the study revealed that at the construction stage, wood (80.5%), aluminium (88.55), sandcrete (85.0%), and ceramic (85.5) were mostly the form of waste generated, while at the post-construction stage, wire and cables (19.3%) were the mostly form of waste generated. However, the findings from this study provide a valuable reference for practitioners to develop and adopt strategic guides for managing material wastes on building construction projects across building construction stages that imbibes principle of sustainable construction.

The study was aimed to assess the factors influencing waste generation in buildings project in southwestern, Nigeria. The study randomly sampled 261 professionals through a questionnaire survey. Tables and figures were used to present the collected data and ranking and percentage were used to analyze the data collected. It was revealed that Design (Frequent design changes and poor design) lack of early contractor involvement, last-minute client requirement, engagement of inexperience designer, undefined project brief, poor design quality are the most important factors that influence l waste generation during buildings project. It was recommended that site operatives and craft men should be equipped with waste minimization knowledge, they should carry along in every management decision regarding waste management plan development as a major player on sites.