Ayodeji Oluleye - Academia.edu (original) (raw)

Papers by Ayodeji Oluleye

Journal of Health and Pollution, 2021

Background. Nitrogen dioxide (NO2) is known to affect human health, causing heart and cardiovascu... more Background. Nitrogen dioxide (NO2) is known to affect human health, causing heart and cardiovascular diseases, and it has been shown that locations with long term NO2 pollution recorded a high number of fatalities due to the COVID-19 pandemic. There are no ground stations monitoring emissions of NO2 over West Africa. The present study aimed to use satellite observations to examine pollutant trends over this region. Objective. To examine the trend of NO2 over the entire West Africa sub region in relationship to contributions to environmental emissions using satellite-derived data. This enables the assessment of West Africa regional air pollution hot spots in relationship to enhancing atmospheric factors. The results from this study will also be useful guidance for setting air quality standards for air pollution controls to minimize health hazards. Methods. The present study examined thirteen years of average monthly values of nitrogen dioxide (NO2) to determine the spatio-temporal va...

Journal of Climatology & Weather Forecasting, 2017

Mesoscale Convective Systems (MCSs) form an important component of meteorology in West Africa, an... more Mesoscale Convective Systems (MCSs) form an important component of meteorology in West Africa, and in particular, contribute substantially to precipitation totals. Several authors focused majorly on the contribution of these systems to precipitation and the damages that accompanied it. But in the event of current climate change, it is expected that storm occurrences especially over the tropics will also be impacted due to variability or changing in climate especially in Northern Nigeria which has experienced some extreme weather events over the years. The study was carried out in eight (8) different states within the savannah region of Nigeria. Monthly total rainfall, mean monthly temperature, relative humidity and daily Mesoscale Convective Systems (MCSs) (thunderstorms and line squalls) data of 31 years was used. Man-Kendall and Coefficient of variation (CV) method were used to analyze the data. There were various degrees of variations in some of the data analyzed based on the location of the station. The frequency of occurrence of these systems showed that its number (peals) decreases with an increasing latitude for stations north of 10 o N with the northeastern part of the country recording a decrease of almost one-third between 1981 and 2010. Hence, monsoon type of precipitation can be seen to be contributing more to the total annual rainfall in the northern part of Nigeria in contrast to earlier studies which gave Mesoscale Convective Systems (MCSs) 95% contribution rate.

Advances in Research, 2017

This study aims at analyzing the influence of rainfall and temperature on Total Column Ozone (TCO... more This study aims at analyzing the influence of rainfall and temperature on Total Column Ozone (TCO) over West Africa. It provides adequate information on the spatial variability of total column ozone concentration, temperature distribution across latitudinal zones, monthly distribution and inter-annual variability of total ozone column and interrelationship between monthly ozone and distribution of precipitation rate over West Africa. The result of this work shows that, there are significant interconnectivities between total ozone column variability with precipitation and temperature. The correlation between Annual coefficient of Relative Variation (ACRV) of Total Column Ozone (TCO) with average annual temperature and average precipitation shows that there is correlation in ACRV of total ozone column trends over West Africa with temperature and precipitation. A strong positive value correlation was observed between the ACRV of ozone and average annual temperature which increases from 25°C to 29°C at the hot arid north of the region and the mean monthly maximum ozone Coincides with the tropical summer rainfall over West Africa between June and September, which showed that there is a significant relationship between rainfall and total ozone column over West Africa. Temperature and ozone tend to increase across the latitude while rainfall decreases across the latitude. These observations suggest significant Original Research Article

Global Journal of Human Social Science Research, Aug 31, 2012

The Sahelian West Africa (Long 20W:20E, Lat 0:30N) by its climatological and geographical conditi... more The Sahelian West Africa (Long 20W:20E, Lat 0:30N) by its climatological and geographical conditions is a key region for the characterization of global atmospheric aerosol optical properties. This study evaluates the spatial and temporal variation of the Aerosol Optical Depth (AOD440nm), aerosol particle size characterization (Angstrom exponent (α440-675nm) at four locations (Agoufou, Banizoumbou, Cape Verde and Ilorin) over a period of January 2005 to December 2009. Results of the day-today AOD440nm variations as well as the seasonal and annual variations are presented in order to establish the aerosol climatology in the region. We compared satellite derived data of Total Ozone Mapping Spectrometer-Aerosol Index (TOMS-AI), MODIS (Terra and Aqua) with those of ground-based Sunphotometer AERONET measurements. In general, there exits good relationship between MODIS (Terra and Aqua) and the ground-based AERONET measurements with correlation coefficients, R2 › 0.8 reported in all stations. However low coefficients (as low as 0.40) were obtained in all the stations for regressions between TOMS AI and ground-based Sunphotometer AERONET data.

Energy & Environment, 2011

The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nig... more The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nigeria. Among the significant industries in the locality is the Nigerian natural gas liquefying plants. The plant complex generates emissions which are propagated by meteorological agents. An atmospheric dispersion model was used to model the emissions using a computer programme. A statistical analysis of meteorological parameters was also carried out to determine the pollutants dispersion in the atmosphere. The analysis shows that wind speed is moderate and the predominance of southerly winds will move plumes toward human settlements in the north and north-eastern directions from the plant. From the diffusion model, the compounds likely to be emitted in the largest quantity from the plant in the order of magnitude were CO2, NOx, CO, PM10 and SOx. There is evidence that pollutants concentration would be highest for receptors at about 10 km from the emission sources even under unstable atmo...

Journal of Pollution Effects & Control, 2017

Pathogens in the dust suspended in the atmosphere are known to cause sickness such as cough and t... more Pathogens in the dust suspended in the atmosphere are known to cause sickness such as cough and throat problems. An unusual dust episode occurred over the coast of West Africa Gulf of Guinea between March 20 th and March 29 th in 2010. The occurrence was seen as unusual because of the time of occurrence. The cause of the dust outbreak was investigated using wind data at various pressure levels from ECMWF Re-Analysis (ERA) interim dataset. Data of horizontal visibility from two near the coast locations were used to calculate the dust load during the period. Results show that dust load during the episode was about 15 × 10 5 kg and 3 × 10 5 kg per square kilometer over Akure and Lagos respectively. Also that winds at the African Easterly Jet level (core at 750 hPa) suddenly changed from westerly to easterly thereby causing the reversal of Planetary Boundary Layer (PBL) winds. Since the dusts are embedded in within the PBL, wind reversal brought load of dust to the south coast of Gulf of Guinea at very unusual time of the year. The study concludes that watching and monitoring winds at the AEJ level could help in predicting dust pollution outbreak over West Africa.

The African Journal of Information Systems, 2013

International Journal of Remote Sensing, May 1, 2011

Surface reflectivity (RFL), solar zenith angle (SZA), ozone and aerosol index (AI) daily data ove... more Surface reflectivity (RFL), solar zenith angle (SZA), ozone and aerosol index (AI) daily data over Lagos (6.60° N, 3.33° E) measured by the Total Ozone Mapping Spectrometer (TOMS) were examined to determine the relationship between the parameters. We found that aerosol distribution can fully account for changes in RFL in the presence of ozone when other factors are held constant.

2015 International Conference on Industrial Engineering and Operations Management (IEOM), 2015

2 Abstract: In this study, the single machine bicriteria scheduling problem of hierarchically min... more 2 Abstract: In this study, the single machine bicriteria scheduling problem of hierarchically minimizing the total completion time of jobs (C ) and number of tardy jobs (NT) with release time was explored. Two types of tot hierarchical minimization models (the case of the total completion time criterion being more important than the number of tardy jobs criterion and the case of the number of tardy jobs criterion being more important than the total completion time criterion) were discussed. Three heuristics (HR4, HR5 and HR6) selected from the literature were used to test the models.

International Journal of Remote Sensing, 2012

Aerosol index (AI) observations from the Total Ozone Mapping Spectrometers (TOMS) on board the Ni... more Aerosol index (AI) observations from the Total Ozone Mapping Spectrometers (TOMS) on board the Nimbus-7 (1979–1992) and Earth Probe (1997–2004) satellites are used to investigate the annual and seasonal variations of dust haze in Sahelian West Africa. Eight synoptic stations, namely Port Harcourt (PHA), Lagos, Ilorin, Makurdi, Minna, Yola, Maiduguri and Kano, representing the four major climatic zones (tropical rainforest

International Journal of Engineering Research in Africa, 2011

ABSTRACT This paper considers the bicriteria scheduling problem of minimizing the total earliness... more ABSTRACT This paper considers the bicriteria scheduling problem of minimizing the total earliness and the total tardiness on a single machine with release dates. In view of the fact that the problem has been characterized as NP-Hard, we propose two approximation algorithms (labeled as ETA1 and ETA2) for solving the problem. The proposed algorithms were compared with the MA heuristic selected from the literature. The two criteria (the total earliness and the total tardiness) were aggregated together into a linear composite objective function (LCOF). The performances of the algorithms were evaluated based on both effectiveness and efficiency. The algorithms were tested on a set of 1200 randomly generated single machine scheduling problems. Experimental results show that both the ETA1 and ETA2 algorithms outperformed (in terms of effectiveness and efficiency) the MA heuristic under all the considered problem sizes. Also, the ETA1 algorithm outperformed the ETA2 algorithm when the number of jobs (n) ranges between 20 and 500.

Advanced Materials Research, 2007

Abstract: This paper focuses on the problem of scheduling n jobs with release dates on a single m... more Abstract: This paper focuses on the problem of scheduling n jobs with release dates on a single machine in order to minimize the total completion time. Since the problem has been characterized as strongly NP-hard, two heuristics (HR1 and AEO) were proposed for solving the ...

Atmospheric Pollution Research, 2013

ABSTRACT The aim of this study was to examine the temporal and spatial total column ozone distrib... more ABSTRACT The aim of this study was to examine the temporal and spatial total column ozone distribution in West Africa using Total Ozone Mapping spectrometer (TOMS) daily data for five years between 2001 and 2005 in fifteen locations. In this study, certain significant observations emerged: weather activity particularly the rainfall producing mechanism (dynamic of the wind systems) was responsible for about 62% ozone distribution in the region. Ozone maximum and minimum concentrations over all the stations were 305 DU and 232 DU respectively producing an average range of 73 DU (only about 27.03% of the mean value). Ozone has a seasonal distribution with minimum occurring during the dry season and maximum occurring during the wet season. A decreasing rate of about –0.6 DU/year was found for the region. Interannual ozone characteristics revealed an oscillating feature similar to Quasi – biennial Oscillation (QBO) footprints which indicated the importance of stratosphere – troposphere exchange to ozone distribution in the region. Furthermore, lag of about one or two months occurs between south (lower latitude) and north (higher latitude) monthly ozone maximums. Keywords: Ozone, West Africa, south westerly winds, north easterly winds, QBO

Advanced Materials Research, 2011

ABSTRACT In this paper, the scheduling problem involving optimization of multiple criteria (or ob... more ABSTRACT In this paper, the scheduling problem involving optimization of multiple criteria (or objectives) is explored. There are many variants of the problem. The particular variant, in which the objectives are aggregated into a scalar function (with each criterion having weight which denotes its relative importance), is considered. An algorithm which can be used to solve very large classes of the multicriteria scheduling problem is proposed. The proposed algorithm and two solution methods selected from the literature were evaluated on a total of 900 randomly generated multicriteria scheduling problems (ranging from 10 to 500 jobs). Two variants of the release dates (0 – 24 and 0 – 49) are utilized. Results show that the proposed algorithm performed better than the selected solution methods when the total completion time criterion is much more important than the other criteria. However, when the total completion time criterion is much less important than the other criteria, the selected solution methods outperformed the proposed algorithm. The results are consistent under the two variants of the release dates.

International Journal of Advancements in …, 2011

This paper considers the single criterion scheduling problem of minimizing makespan on a single m... more This paper considers the single criterion scheduling problem of minimizing makespan on a single machine with release dates. The problem is, by nature, NP-Hard, hence approximation algorithms are desired in order to solve the problem. An algorithm (called NAL) is proposed for the problem. The NAL algorithm is compared with the branch and bound (BB) method and a test algorithm (AEO) selected from the literature. The three solution methods were tested on a set of randomly generated problems (ranging from 10 to 500 jobs). Experimental results show that the proposed algorithm performed competitively with the BB method and outperformed the AEO algorithm.

International Journal of Remote Sensing, 2012

Energy & Environment, 2011

The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nig... more The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nigeria. Among the significant industries in the locality is the Nigerian natural gas liquefying plants. The plant complex generates emissions which are propagated by meteorological agents. An atmospheric dispersion model was used to model the emissions using a computer programme. A statistical analysis of meteorological parameters was also carried out to determine the pollutants dispersion in the atmosphere. The analysis shows that wind speed is moderate and the predominance of southerly winds will move plumes toward human settlements in the north and north-eastern directions from the plant. From the diffusion model, the compounds likely to be emitted in the largest quantity from the plant in the order of magnitude were CO 2 , NO x , CO, PM 10 and SO x . There is evidence that pollutants concentration would be highest for receptors at about 10 km from the emission sources even under unstable atmospheric conditions. The concentration of all the pollutants were well within the set ambient limits for the averaging period considered (i.e., 1 hour). It is recommended that the LNG plants continue to use natural gas as their major fuel as it will help in reducing pollutants like CO, PM 10 and SO x . Also, due to the large CO 2 gas emitted, afforestation and conservation projects should be initiated in Bonny Island so as to earn carbon credit.

Journal of Health and Pollution, 2021

Journal of Climatology & Weather Forecasting, 2017

Advances in Research, 2017

Global Journal of Human Social Science Research, Aug 31, 2012

Energy & Environment, 2011

Journal of Pollution Effects & Control, 2017

The African Journal of Information Systems, 2013

International Journal of Remote Sensing, May 1, 2011

2015 International Conference on Industrial Engineering and Operations Management (IEOM), 2015

International Journal of Remote Sensing, 2012

International Journal of Engineering Research in Africa, 2011

Advanced Materials Research, 2007

Atmospheric Pollution Research, 2013

Advanced Materials Research, 2011

International Journal of Advancements in …, 2011

International Journal of Remote Sensing, 2012

Energy & Environment, 2011

The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nig... more The Bonny Island axis of the Niger Delta, Nigeria, is one of the most industrialized belts of Nigeria. Among the significant industries in the locality is the Nigerian natural gas liquefying plants. The plant complex generates emissions which are propagated by meteorological agents. An atmospheric dispersion model was used to model the emissions using a computer programme. A statistical analysis of meteorological parameters was also carried out to determine the pollutants dispersion in the atmosphere. The analysis shows that wind speed is moderate and the predominance of southerly winds will move plumes toward human settlements in the north and north-eastern directions from the plant. From the diffusion model, the compounds likely to be emitted in the largest quantity from the plant in the order of magnitude were CO 2 , NO x , CO, PM 10 and SO x . There is evidence that pollutants concentration would be highest for receptors at about 10 km from the emission sources even under unstable atmospheric conditions. The concentration of all the pollutants were well within the set ambient limits for the averaging period considered (i.e., 1 hour). It is recommended that the LNG plants continue to use natural gas as their major fuel as it will help in reducing pollutants like CO, PM 10 and SO x . Also, due to the large CO 2 gas emitted, afforestation and conservation projects should be initiated in Bonny Island so as to earn carbon credit.