| 1. |
- Maina, David M., et al.
(författare)
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Environmental implications of high metal content in soils of a titanium mining zone in Kenya
- 2016
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 23:21, s. 21431-21440
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Tidskriftsartikel (refereegranskat)abstract
- Mining activities contribute to an increase of specific metal contaminants in soils. This may adversely affect plant life and consequently impact on animal and human health. The objective of this study was to obtain the background metal concentrations in soils around the titanium mining in Kwale County for monitoring its environmental impacts. Forty samples were obtained with half from topsoils and the other from subsoils. X-ray fluorescence spectrometry was used to determine the metal content of the soil samples. High concentrations of Ti, Mn, Fe, and Zr were observed where Ti concentrations ranged from 0.47 to 2.8%; Mn 0.02 to 3.1%; Fe 0.89 to 3.1%; and Zr 0.05 to 0.85%. Using ratios of elemental concentrations in topsoil to subsoil method and enrichment factors concept, the metals were observed to be of geogenic origin with no anthropogenic input. The high concentrations of Mn and Fe may increase their concentration levels in the surrounding agricultural lands through deposition, thereby causing contamination on the land and the cultivated food crops. The latter can cause adverse human health effects. In addition, titanium mining will produce tailings containing low-level titanium concentrations, which will require proper disposal to avoid increasing titanium concentrations in the soils of the region since it has been observed to be phytotoxic to plants at high concentrations. The results of this study will serve as reference while monitoring the environmental impact by the titanium mining activities.
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| 2. |
- Boman, Johan, 1955, et al.
(författare)
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ASSESSING THE ENVIRONMENT WITH X-RAY FLUORESCENCE
- 2011
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Ingår i: Advances in X-ray Analysis. - 0376-0308. ; 54, s. 266-279
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we will introduce the general benefits of X-Ray Fluorescence spectrometry (XRF) for assessing the condition of the outer environment, especially where ambient aerosol particles are causing environmental disturbances. Examples from recent environmental studies are presented, and energy dispersive XRF is concluded to be a powerful, nondestructive yet easily applicable tool to supply detailed elemental information of particles collected in different applications. The further development and future potential of the method for detailed analysis of aerosol particles are discussed.
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| 3. |
- Boman, Johan, 1955, et al.
(författare)
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Elemental characterization of aerosols in urban and rural locations in Bangladesh
- 2005
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Ingår i: X-Ray Spectrometry. - : Wiley. - 0049-8246 .- 1097-4539. ; 34:5, s. 460-467
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Tidskriftsartikel (refereegranskat)abstract
- Bangladesh became the first country in South Asia to ban the use of lead in gasoline in 1999. In 2003, two-stroke engine auto rickshaws were banned in the city centre of Dhaka, the capital of Bangladesh and one of the Asian mega-cities, in an attempt to improve the air quality. In July and August 2003, fine aerosol particles (PM2.5) were collected in Dhaka and in Rangpur in the northern part of the country. The aim was to study the effect of the action and to characterize PM2.5 particles in urban and rural areas of Bangladesh. Sampling was done with a cyclone of Dewell-Higgins type equipped with Teflon filters with a pore size of 3 mu m. Day- and night-time filters were collected in an attempt to understand the possible difference in air pollution between the two periods. An energy-dispersive x-ray fluorescence (EDXRF) spectrometer with three-axial geometry was utilized for the analysis of the elemental content of the particles. Large variations of concentrations for most elements in both Dhaka and in Rangpur were observed. Most of the elemental concentrations in Dhaka in daytime were higher than at night whereas the opposite was the case for Rangpur. The concentrations showed a significant influence of human activities and weather. Considerable concentrations of Pb were found despite the official ban of leaded gasoline. Motor transport, especially the two-stroke engine taxis and elements remobilized by burning, were the major sources identified. This is the first report on elemental concentrations in PM2.5 particles in both Dhaka and Rangpur. Copyright (c) 2005 John Wiley & Sons, Ltd.
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| 4. |
- Boman, Johan, 1955, et al.
(författare)
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Elemental content of PM2.5 aerosol particles collected in Göteborg during the Göte-2005 campaign in February 2005
- 2008
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Ingår i: Atmos. Chem. Phys. Discuss. ; 8:2, s. 7703-7724
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Tidskriftsartikel (refereegranskat)abstract
- Göte–2005 was a measurement campaign in the city of Göteborg with the aim of studying the influence of the winter thermal inversions on urban air pollution. Elemental speciation of PM2.5 aerosol particles, collected on Teflon filters at three urban sites and one rural site in the Göteborg region, was a major part of the study. Trace element analysis was done by Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry and the concentrations of S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Pb were determined. The elemental content of the particles in combination with information of local wind speed and direction and also backward trajectories were used to estimate the source areas of the pollutants. We can conclude that S, V, Ni, Br, and Pb have their main sources outside the Göteborg area, since we cannot see elevated concentrations of these elements during an inversion episode. Sea traffic and harbour activities were also identified, primarily by the S and V content of the particles. This study proves that the elemental analysis by EDXRF presents valuable information for tracing the origin of air masses arriving at a measurement site.
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| 5. |
- Boman, Johan, 1955, et al.
(författare)
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Elemental content of PM2.5 aerosol particles collected in Göteborg during the Göte-2005 campaign in February 2005
- 2009
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 9, s. 2597-2606
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Tidskriftsartikel (refereegranskat)abstract
- The Göte-2005 measurement campaign aimed at studying the influence of the winter thermal inversions on urban air pollution. Elemental speciation of PM2.5 aerosol particles, collected on Teflon filters at three urban sites and one rural site in the Göteborg region, was a major part of the study. Trace element analysis was done by Energy Dispersive X-Ray Fluorescence (EDXRF) spectrometry and the concentrations of S, Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Pb were determined. The elemental content of the particles, local wind speed and direction, and backward trajectories were used to investigate possible sources for the pollutants. We concluded that S, V, Ni, Br, and Pb had their main sources outside the central Göteborg area, since elevated concentrations of these elements were not observed during an inversion episode. Sea traffic and harbour activities were identified, primarily by the S and V content of the particles. This study showed that the elemental analysis by EDXRF presents valuable information for tracing the origin of air masses arriving at a measurement site.
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| 6. |
- Boman, Johan, 1955, et al.
(författare)
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Trace elements in PM2.5 in Gothenburg, Sweden
- 2010
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Ingår i: Spectrochimica Acta - Part B: Atomic Spectroscopy. - : Elsevier BV. - 0584-8547. ; 65:6, s. 478-482
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Tidskriftsartikel (refereegranskat)abstract
- Ambient aerosol particles smaller than 2.5 µm (PM2.5) are getting more and more attention worldwide. While legal focus is mainly on sample mass, the composition of the particles is an important research field gaining increased interest. The interest is not only connected to possible health effects of the elemental content of the particles, but the elemental determination can also add valuable information for source apportionment. Samples were collected during 20 days in November 2007 at the campus of the Chemistry Department, University of Gothenburg, Gothenburg, Sweden. The particles were collected using a cyclone that separates the PM2.5 particles from the air stream and impacts them on polycarbonate filters. Filters were changed at early afternoon. The samples were analyzed for particulate mass, black carbon (BC) and the elements S, Cl, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, As, Br, Cd and Pb. Several of the elements were above detection limit in only a few of the samples. Total reflection X-ray fluorescence (TXRF) spectrometer based on the Wobi TXRF module supplied by the International Atom Energy Agency (IAEA) has been used for the determination of most trace elements in the samples. A Graphite Furnace Atomic Absorption Spectrometer (GF-AAS) was used for complementary trace element analysis and a reflectometer was used to analyze black carbon. Before elemental analysis the filters were digested using a microwave digestion system with temperature and pressure control. The results showed a large variation in sample mass, BC and analyzed elemental concentrations. The variation of the different constituents did not show the same pattern. This added to the picture of different sources for different pollutants. The highest S concentration was noted on a day when the air masses were determined to come from the southeast, i.e. Poland and some other Eastern European countries. From the results it can be concluded that more work is needed on the TXRF spectrometer to optimize it for determination of the EU legally regulated elements As, Ni, Pb and Cd. Despite this the study shows that there is no problem in meeting the AAQS limits for Cd and Pb in Gothenburg.
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| 7. |
- Gaita, Samuel Mwaniki, 1976, et al.
(författare)
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Characterization of Size-Fractionated Particulate Matter and Deposition Fractions in Human Respiratory System in a Typical African City: Nairobi, Kenya
- 2016
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 2071-1409 .- 1680-8584. ; 16:10, s. 2378-2385
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Tidskriftsartikel (refereegranskat)abstract
- Information from elemental and mass composition of size-fractionated airborne particle matter (PM) provides insightfulknowledge about their impact on human health, meteorology and climate. To attain insight into the nature of sizefractionatedPM from a typical African city, samples were collected from an urban background site in Nairobi, Kenya,during the months of August and September in 2007. PM samples ranging in size from 0.06 to 16 µm aerodynamicdiameter were collected on pre-weighed polycarbonate filters with 0.4 µm pore size using a nine-stage cascade impactor.Particles less than 0.06 µm were collected on a backup filter. A total of 170 samples were collected and analysed for traceelements using the Proton Induced X-Ray Emission (PIXE) technique. The analysis showed that Si, Fe and S dominated inall size ranges and displayed unimodal mass-size distribution whereas K, Cu, Zn and Pb, depicted bimodal mass-sizedistribution highlighting the multiplicity of their sources. To estimate human exposure to PM, deposition fractions of boththe coarse and fine PM in the human respiratory system were calculated. The deposited concentration was found to behighest in the head airways region compared to the tracheobronchial and pulmonary regions.
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| 8. |
- Gaita, Samuel Mwaniki, 1976, et al.
(författare)
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Source apportionment and seasonal variation of PM2.5 in a Sub-Sahara African city : Nairobi, Kenya
- 2014
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Ingår i: Atmospheric Chemistry And Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 14:18, s. 9977-9991
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Tidskriftsartikel (refereegranskat)abstract
- Sources of airborne particulate matter and their seasonal variation in urban areas in Sub-Saharan Africa are poorly understood due to lack of long-term measurement data. In view of this, filter samples of airborne particulate matter (particle diameter ≤2.5 μm, PM2.5) were collected between May 2008 and April 2010 at two sites (urban background site and suburban site) within the Nairobi metropolitan area. A total of 780 samples were collected and analyzed for particulate mass, black carbon (BC) and 13 trace elements.The average PM2.5 concentration at the urban background site was 21±9.5 μg m−3, whereas the concentration at the suburban site was 13±7.3 μg m−3. The daily PM2.5 concentrations exceeded 25 μg m−3 (the World Health Organization 24 h guideline value) on 29% of the days at the urban background site and 7% of the days at the suburban site. At both sites, BC, Fe, S and Cl accounted for approximately 80% of all detected elements. Positive matrix factorization analysis identified five source factors that contribute to PM2.5 in Nairobi, namely traffic, mineral dust, industry, combustion and a mixed factor (composed of biomass burning, secondary aerosol and aged sea salt).Mineral dust and traffic factors were related to approximately 74% of PM2.5. The identified source factors exhibited seasonal variation, apart from the traffic factor, which was prominently consistent throughout the sampling period. Weekly variations were observed in all factors, with weekdays having higher concentrations than weekends. The results provide information that can be exploited for policy formulation and mitigation strategies to control air pollution in Sub-Saharan African cities.
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| 9. |
- Gatari, Michael J, et al.
(författare)
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Assessment of inorganic content of PM(2.5) particles sampled in a rural area north-east of Hanoi, Vietnam.
- 2006
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Ingår i: The Science of the total environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 368:2-3, s. 675-85
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric aerosols from seven rural sites in northern Vietnam, east of Hanoi, were sampled and analyzed. The aim of the study was to evaluate trace elemental and black carbon (BC) concentrations in fine particles (PM(2.5)) and to investigate the influence of the Pha Lai power plant and other pollution sources on regional air quality. Seven measurement stations were set up at selected rural sites and a campaign consisting of 12 two-day measurement periods was conducted from the end of May until the end of October 2000. At each location a pair of samplers was installed consisting of a cyclone loaded with Teflon filters and a modified Millipore air monitoring cartridge loaded with glass fibre filters. The obtained samples were analyzed for trace elements by Energy Dispersive X-ray Fluorescence (EDXRF), while a black smoke detector was used for BC analysis. Seventeen trace elements were analyzed; Br, Ca, Cl, Cr, Cu, Fe, K, Mn, Ni, Pb, Rb, S, Se, Sr, Ti, V and Zn and their concentrations evaluated. The results showed that BC, Ca, Cl, Fe, K and S dominated in the sampled atmospheric aerosols. The measured concentrations of the potentially hazardous trace elements Cr, Mn, Ni and Pb were all below the limits defined by Vietnamese standards of ambient air quality. Statistical evaluations indicated that coal and heavy fuel oil combustion were major sources of atmospheric pollutants in the area and that biomass burning and road transport had a marked influence on regional air quality. It was concluded that the Pha Lai power plant was the major source of coal combustion emissions. Trace element emissions originating from river transportation were suggested as another major source of atmospheric pollutants. The results indicate that the elemental concentrations in PM(2.5) are strongly influenced by seasonal variations. Further measurements are required to identify the impact of long-range transported continental air masses on the air quality of the investigated rural area.
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| 10. |
- Gatari, Michael J, et al.
(författare)
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Elemental composition of tropospheric aerosols in Hanoi, Vietnam and Nairobi, Kenya.
- 2005
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Ingår i: The Science of the total environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 341:1-3, s. 241-9
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Tidskriftsartikel (refereegranskat)abstract
- Air pollution problems in major cities within the developing countries need to be studied. There are scanty measurements from the developing countries on airborne particles despite their adverse implications to human health, visibility and climate. One of the major sources of anthropogenic air pollution is energy production. Energy demand is bound to increase as population increases, especially in major cities of the world. Fine particles, particles with aerodynamic diameter < or = 2.5 microm, are mainly anthropogenic and these particles were collected in the capital cities of Vietnam and Kenya. A cyclone airborne particle collector was used to sample in Hanoi during the months of May to October 2000 and a dichotomous virtual impactor in Nairobi in February 2000. The samples were analysed for elemental content by an energy dispersive X-ray fluorescence (EDXRF) spectrometer. S, Cl, K and Fe exceeded atmospheric concentrations of 100 ng m(-3) at both cities. Atmospheric elemental concentrations in both Hanoi and Nairobi were orders of magnitude higher than their respective rural towns. Traffic, biomass and waste burning emissions were implicated as the main sources of air pollution in Nairobi, while coal combustion and road transport were the major sources in Hanoi. Regional air pollution had a major impact over Hanoi, whereas an influence of that kind was not identified in Nairobi. Pb and other toxic elements had concentration levels below WHO guideline, however, the two cities are threatened by future high levels of air pollution due to the high rate of population growth. Long-term measurements are required in both areas to evaluate if the alarming situation is deteriorating.
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