I.B. Obioh

PIXE characterization of PM10 and PM2.5 particulates sizes collected in Ikoyi Lagos, Nigeria

Ambient concentrations of PM10 (xu2009≤u200910u2009µm) and PM2.5 (xu2009≤u20092.5u2009µm) particulate fractions collected from Ikoyi Lagos, Nigeria, as well as their elemental compositions are presented in this study. Both size-segregated fractions were collected using a double staged ‘Gent’ stack filter unit sampler. Elemental characterizations of dust laden filters were carried out using proton-induced X-ray emission (PIXE) technique. Twenty-two elements (Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pb, Br, Rb, Sr, Zr, Ag, Cd, and Ta) were detected as well as their concentrations and correlations were determined for both particulate size fractions. Their correlation matrix result indicates that some of the trace elements detected could have common source origins or similar chemical properties. The results were similar to the levels observed in moderately polluted urban areas and there is need for source identification and apportionment using receptor models in future studies.

Atmospheric particulate matter in Nigerian megacities

The paucity of data on air pollution indices in Nigeria prompted us to commence a national screening exercise regarding particulate matter loads. Six potential megacities (Aba, Abuja, Lagos, Kano, Maiduguri, and Port-Harcourt) representing the six geographical zones in Nigeria were chosen for the study. Sampling was achieved using a ‘Gent’ stacked filter unit sampler capable of collecting fractions of particulate matter with sizes of <10-μm and <2.5-μm simultaneously. The mean values for PM10 are 550, 35, 87, 340, 246 and 130 μg m−3 while for PM2.5 the mean values are 100, 14, 25, 67, 20 and 30 μg m−3 respectively for Aba, Abuja, Lagos, Kano, Maiduguri, and Port-Harcourt. Except for Abuja, the daily PM10 mass loads exceeded the World Health Organization (WHO) guidelines daily limit where as the PM2.5 values were within the WHO guideline limit. Their correlation matrix result indicates that some PM2.5 fractions mass fractions were strongly correlated than the PM10 fractions probably due to their long range transport potentials. Further work is in progress to determine the elemental profiles of both particulate fractions collected.

Determination of elemental composition of TSP from cement industries in Nigeria using EDXRF technique

Abstract Suspended dust particulates within and around cement industries in Nigeria were sampled and analyzed using EDXRF technique. The TSP concentrations ranged from 500 μg/m 3 to 1300 μg/m 3 within the factory, while outside the factory the range is from 100 μg/m 3 to 370 μg/m 3 . In major shop floors, particulate matter concentrations as high as 10 4 μg/m 3 were recorded. Elements detected include Na, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Zn, S, Cu and Pb. Highly enriched elements were Ca, S, Zn, Cu and Pb with enrichment factors 30–350, 75–200, 100–14 700 and 20–700 respectively. Elements such as Al, Fe, Mn, Na, V and Cr were moderately enriched. Source apportionment of the pollutants by chemical mass balance (CMB) and factor analysis methods revealed cement contributions up to 60% within the factory and 30% around the residential neighbourhoods. Control measures like electrostatic precipitators have been strongly suggested to these factories.

Non-CO2 Gaseous Emissions from Upstream Oil and Gas Operations in Nigeria

The Nigerian crude oil is formed in association with natural gas. The associated gas has mostly been flared in the process of crude oil exploitation. Current estimates are that approximately 70% of produced natural gas is flared. Carbon monoxide, volatile organic compounds and nitrogen oxides emissions from oil and gas exploitation activities are presented for major combustion activities: gas flares and power generation at oil fields for oil and gas gathering systems. The emissions rates and combustion efficiency for a newly tested modified flaring system with enhanced air supply and liquid aspiration system for the atomization of the condensate phases of the flared gas was found to be capable of improving combustion efficiency by 20% or more in comparison with the conventional flare-type currently in vogue. Flare emissions for CO and NOx are an order of magnitude higher than other sources in the oil and gas sector.

Climate change mitigation policy paradigms—national objectives and alignments

The aim of this paper is to assess how policy goals in relation to the promotion of green growth, energy security, pollution control and greenhouse gas (GHG) emissions reductions have been aligned in policies that have been implemented in selected countries during the last decades as a basis for discussing how a multi objective policy paradigm can contribute to future climate change mitigation. The paper includes country case studies from Brazil, Canada, China, the European Union (EU), India, Japan, Mexico, Nigeria, South Africa, South Korea and the United States covering renewable energy options, industry, transportation, the residential sector and cross-sectoral policies. These countries and regions together contribute more than two thirds of global GHG emissions. The paper finds that policies that are nationally driven and that have multiple objectives, including climate-change mitigation, have been widely applied for decades in both developing countries and industrialised countries. Many of these policies have a long history, and adjustments have taken place based on experience and cost effectiveness concerns. Various energy and climate-change policy goals have worked together in these countries, and in practice a mix of policies reflecting specific priorities and contexts have been pursued. In this way, climate-change mitigation has been aligned with other policy objectives and integrated into broader policy packages, though in many cases specific attention has not been given to the achievement of large GHG emission reductions. Based on these experiences with policy implementation, the paper highlights a number of key coordination and design issues that are pertinent to the successful joint implementation of several energy and climate-change policy goals.

Characterization of pollutants around tin mining and smelting operations using EDXRF

Abstract Energy dispersive X-ray fluorescence (EDXRF) in combination with HpGe based passive gamma spectrometry is used to measure the concentration of toxic heavy metals and radionuclides in the soils around a lead/tin smelter and also air particulates and mining wastes collected from some tin mines and a tin mill. Toxic heavy metals like Sn, Pb, As, Zn, Bi and Ni were detected and found to be highly enriched in the soils, air particulates and mine wastes. The concentrations of Th and U ranged between 0.01 and 2.94%, and 0.002 and 0.11% in the tailings and between 2.25 and 9.09%, and 0.25 and 0.56% in the monazites respectively. The radiological waste management implications are discussed.

Emission inventory for Nigeria with CAREAIR.

CAREAIR is the abbreviation for “Computer aided Analysis of Reduction strategies for Emissions and ambient AIR pollution”. It is a modelling-system for air pollution analyses including a flexible emission model developed at the IER. The PC-based version of the system is especially designed for applications in so-called 3rd-world countries, but in fact it can be used for any country. A modeling database for many emission relevant processes and related emission factors is part of it. This paper first gives a short overview on the capabilities of CAREAIR and secondly presents part of the emission inventory for Nigeria, which has been elaborated using CAREAIR during a cooperation between the University of Stuttgart (FRG) and the Obafemi Awolowo University of Ile-Ife (Nigeria). In particular estimates of the yearly emissions of total Hydrocarbons (VOC = Volatile Organic Compounds), divided into CH4 (Methane) and NMVOC (Non-Methane-VOC), NOx (Nitrogen Oxides), N2O (Nitrous Oxide), CO2 (Carbon Dioxide) and CO (Carbon Monoxide) emissions in Nigeria 1989 are given.

Trace elements in particulate matter of ambient air at petroleum filling stations

Size segregated suspended particulate matter (PM2.5 and PM10-2.5) in air at four major petroleum-filling stations in Ile-Ife, Nigeria, were monitored using double staged “Gent” stacked samplers to assess variations in mass loads and elemental concentrations of 25 elements. Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, Cs, Ta, W, and Pb were determined in both fractions by external ion beam proton-induced X-ray emission technique. Enrichment factors and pollution indices were calculated and results revealed that most elements were anthropogenic in both fractions with concentrations exceeding the World Health Organization guideline standards.

Airborne fine particulate matter (PM2.5) at industrial, high- and low-density residential sites in a Nigerian megacity

Abstract Airborne particulate matter PM2.5 was collected in an industrial, a low-density, and a high-density residential area of Lagos from December 2010 to November 2011, and elemental composition was determined by proton-induced X-ray emission. Across the months, mass concentrations ranged from 13 to 237u2009µgu2009m−3, exceeding the World Health Organization guideline value of 10u2009µgu2009m−3. Data on 24 elements were obtained, with maximum values during Harmattan season months; source identification and apportionment studies by positive matrix factorization suggested that petroleum oil combustion (70%) was the major source of PM2.5 and could pose a great hazard to Lagos receptors.

Elemental analyses and source apportionment of PM2.5 and PM2.5–10 aerosols from Nigerian urban cities

Abstract PM2.5 and PM2.5–10 aerodynamic diameters (x ≤ 2.5 μm) and (2.5 ≥ x ≤ 10 μm) fractions in six Nigerian urban cities (Aba, Abuja, Lagos, Kano, Maiduguri and Port-Harcourt), were monitored using “Gent” stacked filter unit sampler in order to assess elemental concentrations and to perform source apportionment. Twenty-three elements; (Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr and Pb) were analysed with Ion beam analysis (IBA) based proton induced X-ray emission (PIXE) technique. In addition, enrichment factors (EF) and pollution indices (PI) calculations were performed on the elemental concentration data. Results indicated that the elemental concentration varied across the receptor sites with some elements higher than World Health Organization (WHO) guideline values. PM2.5–10 ranged from 9 to 45,243 ng m−3 (Aba), 1 to 281 ng m−3 (Abuja), 5 to 3,936 ng m−3 (Kano), 6 to 3,872 ng m−3 (Lagos), 6 to 19,106 ng m−3 (Maiduguri) and 4 to 7,962 ng m−3 (Port Harcourt) while PM2.5 ranged from 3 to 7,089 ng m−3 (Aba), 1 to 139 ng m−3, 2 to 480 ng m−3, 1 to 153 ng m−3, 1 to 427 ng m−3 and 1 to 1,051 ng m−3 (Port Harcourt). Principal Component Analysis resolved three (soil dust 50%; sea spray 22% and industrial 15%) and four components (soil dust 42%; biomass burning 24%; petroleum products combustion (15%) and industrial emission 5%) as PM2.5–10 and PM2.5 sources, respectively.