scholarly journals Monitoring Particulate Matter Air Pollution in Urban Centers: New Insights from Douala, Cameroon

2021 ◽  
Vol 8 (2) ◽  
pp. 81-104
Author(s):  
Aguh Akeh Nug ◽  
Cheo Emmanuel Suh ◽  
Johan Boman ◽  
Godwin Sendze Yinda
Keyword(s):  
Air Quality ◽  
Mass Concentration ◽  
Road Traffic ◽  
Trace Element Analysis ◽  
Sampling Period ◽  
Anthropogenic Sources ◽  
Elemental Content ◽  
Health And Environmental Effects ◽  
Element Analysis ◽  
Aerosol Mass Concentration

Air quality progressively deteriorates as urbanization, motorization and economic activities increase. Aerosol particles smaller than 2.5µm (PM2.5), a widespread form of pollution is an emergent threat to human health, the environment, quality of life, and the world’s climate. The composition of these particles is an important aspect of interest not only related to possible health and environmental effects of the elemental content but the elemental determination which also adds valuable information for source apportionment. This study investigates and evaluates the level of PM2.5 in Douala, Cameroon. Particles were collected using a cyclone that separates the PM2.5 from the air stream and impacts them on polycarbonate filters which were changed every 24-hour sampling period. Samples were analyzed for particulate mass concentration, black carbon (BC) and trace elements. Trace element analysis was done by EDXRF (energy dispersive x-ray fluorescence spectroscopy). Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br, Sr, and Pb were identified and quantified for samples. Local meteorology was used to study variations in PM2.5 mass concentrations. Possible sources for the pollutants were also investigated. The mean particle mass concentration was 252 ± 130μg/m3 while BC attained a maximum of 6.993μg/m3. The influence of leaded gasoline was inferred while combustion and road traffic were identified as the major anthropogenic sources. Trends in meteorological parameters were influenced by thunderstorms. Sea spray was identified as another major contributor to aerosol PM. This study highlights high pollution levels in Douala. Keywords: PM2.5, air quality, aerosol, mass concentration, source identification

scholarly journals Elemental content of PM<sub>2.5</sub> aerosol particles collected in Göteborg during the Göte-2005 campaign in February 2005

2009 ◽  
Vol 9 (7) ◽  
pp. 2597-2606 ◽  
Author(s):  
J. Boman ◽  
M. J. Gatari ◽  
S. Janhäll ◽  
A. S. Shannigrahi ◽  
A. Wagner
Keyword(s):  
Aerosol Particles ◽  
Urban Air Pollution ◽  
Trace Element Analysis ◽  
Rural Site ◽  
Elemental Content ◽  
Local Wind ◽  
Element Analysis ◽  
Air Masses ◽  
X Ray ◽  
Urban Sites

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.

scholarly journals Numerical analysis of the impact of agricultural emissions on PM<sub>2.5</sub> in China using a high-resolution ammonia emissions inventory

2020 ◽  
Author(s):  
Xiao Han ◽  
Lingyun Zhu ◽  
Mingxu Liu ◽  
Yu Song ◽  
Meigen Zhang
Keyword(s):  
Air Quality ◽  
High Resolution ◽  
Source Apportionment ◽  
Mass Concentration ◽  
Atmospheric Modeling ◽  
Central China ◽  
High Mass ◽  
Emissions Inventory ◽  
Aerosol Mass Concentration ◽  
The Impact

Abstract. China is one of the largest agricultural countries in the world. The NH3 emissions from agricultural activities in China significantly affect regional air quality and horizontal visibility. To reliably estimate the influence of NH3 on agriculture, a high-resolution agricultural NH3 emissions inventory, compiled with a 1 km × 1 km horizontal resolution, was applied to calculate the NH3 mass burden in China. The key emission factors of this inventory were enhanced by considering the results of many native experiments, and the activity data of spatial and temporal information were updated using statistical data from 2015. Fertilizer and husbandry, as well as farmland ecosystems, livestock waste, crop residue burning, fuel wood combustion, and other NH3 emission sources were included in the inventory. Furthermore, a source apportionment tool, ISAM (Integrated Source Apportionment Method), coupled with the air quality modeling system RAMS-CMAQ (Regional Atmospheric Modeling System and Community Multiscale Air Quality), was applied to capture the contribution of NH3 emitted from total agriculture (Tagr) in China. The aerosol mass concentration in 2015 was simulated, and the results showed that a high mass concentration of NH3, which exceeded 10 μg m−3, appeared mainly in the North China Plain (NCP), Central China (CNC), the Yangtz River Delta (YRD), and the Sichan Basin (SCB), and the annual average contribution of Tagr NH3 to PM2.5 mass burden in China was 14–18 %. Specific to the PM2.5 components, Tagr NH3 provided a major contribution to ammonium formation (87.6 %) but a tiny contribution to sulfate (2.2 %). In addition, several brute-force sensitivity tests were conducted to estimate the impact of Tagr NH3 emissions reduction on the PM2.5 mass burden. Compared with the results of ISAM, it was found that even though the Tagr NH3 only contributed 10.1 % of nitrate under current emissions scenarios, the reduction of nitrate could reach 98.8 % upon removal of the Tagr NH3 emissions. The main reason for this deviation could be that the NH3 contribution to nitrate is small under rich NH3 conditions and large in poor NH3 environments. Thus, the influence of NH3 on nitrate formation could be enhanced with the decrease of ambient NH3 mass concentration.

scholarly journals Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland

2011 ◽  
Vol 11 (17) ◽  
pp. 8945-8963 ◽  
Author(s):  
A. Richard ◽  
M. F. D. Gianini ◽  
C. Mohr ◽  
M. Furger ◽  
N. Bukowiecki ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Road Traffic ◽  
Anthropogenic Activities ◽  
Trace Element Analysis ◽  
Organic Aerosols ◽  
Ambient Air ◽  
Organic Aerosol ◽  
Receptor Modeling ◽  
Element Analysis

Abstract. Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI) and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter <10 μm (PM10) in ambient air. Receptor modeling was performed with positive matrix factorization (PMF) for trace element data from an urban background site in Zürich, Switzerland. Eight different sources were identified for the three examined size ranges (PM1−0.1, PM2.5−1 and PM10−2.5): secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS), assessing the PM1 fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate), hydrocarbon-like organic aerosol (HOA, related to road traffic) and biomass burning organic aerosol (BBOA), explaining 60 %, 22 % and 17 % of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM10 mass concentration can be apportioned to sources by the combination of both methods.

scholarly journals Source apportionment of size and time resolved trace elements and organic aerosols from an urban courtyard site in Switzerland

2011 ◽  
Vol 11 (2) ◽  
pp. 3727-3776 ◽  
Author(s):  
A. Richard ◽  
M. F. D. Gianini ◽  
C. Mohr ◽  
M. Furger ◽  
N. Bukowiecki ◽  
...  
Keyword(s):  
Trace Elements ◽  
Trace Element ◽  
Road Traffic ◽  
Anthropogenic Activities ◽  
Trace Element Analysis ◽  
Organic Aerosols ◽  
Ambient Air ◽  
Organic Aerosol ◽  
Receptor Modeling ◽  
Element Analysis

Abstract. Time and size resolved data of trace elements were obtained from measurements with a rotating drum impactor (RDI) and subsequent X-ray fluorescence spectrometry. Trace elements can act as indicators for the identification of sources of particulate matter <10 μm (PM10) in ambient air. Receptor modeling was performed with positive matrix factorization (PMF) for trace element data from an urban background site in Zürich, Switzerland. Eight different sources were identified for the three examined size ranges (PM1−0.1, PM2.5−1 and PM10−2.5): secondary sulfate, wood combustion, fire works, road traffic, mineral dust, de-icing salt, industrial and local anthropogenic activities. The major component was secondary sulfate for the smallest size range; the road traffic factor was found in all three size ranges. This trace element analysis is complemented with data from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (AMS), assessing the PM1 fraction of organic aerosols. A separate PMF analysis revealed three factors related to three of the sources found with the RDI: oxygenated organic aerosol (OOA, related to inorganic secondary sulfate), hydrocarbon like organic aerosol (HOA, related to road traffic) and biomass burning organic aerosol (BBOA), explaining 60%, 22% and 17% of total measured organics, respectively. Since different compounds are used for the source classification, a higher percentage of the ambient PM10 mass concentration can be apportioned to sources by the combination of both methods.

scholarly journals Elemental content of PM<sub>2.5</sub> aerosol particles collected in Göteborg during the Göte-2005 campaign in February 2005

2008 ◽  
Vol 8 (2) ◽  
pp. 7703-7724 ◽  
Author(s):  
J. Boman ◽  
M. J. Gatari ◽  
S. Janhäll ◽  
A. S. Shannigrahi ◽  
A. Wagner
Keyword(s):  
Aerosol Particles ◽  
Urban Air Pollution ◽  
Trace Element Analysis ◽  
Rural Site ◽  
Elemental Content ◽  
Element Analysis ◽  
Air Masses ◽  
X Ray ◽  
The City ◽  
Urban Sites

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.

An improved interference correction for trace element analysis

1992 ◽  
Vol 50 (2) ◽  
pp. 1646-1647
Author(s):  
John J. Donovan ◽  
Donald A. Snyder ◽  
Mark L. Rivers
Keyword(s):  
Trace Element Analysis ◽  
Accurate Estimate ◽  
Simple Expression ◽  
Standard Reference Materials ◽  
Characteristic Line ◽  
Analytical Line ◽  
Element Analysis ◽  
Electron Probe Analysis ◽  
Calculated Concentration ◽  
X Ray

We present a simple expression for the quantitative treatment of interference corrections in x-ray analysis. WDS electron probe analysis of standard reference materials illustrate the success of the technique.For the analytical line of wavelength λ of any element A which lies near or on any characteristic line of another element B, the observed x-ray counts at We use to denote x-ray counts excited by element i in matrix j (u=unknown; s=analytical standard; ŝ=interference standard) at the wavelength of the analytical line of A, λA (Fig. 1). Quantitative analysis of A requires an accurate estimate of These counts can be estimated from the ZAF calculated concentration of B in the unknown C,Bu measured counts at λA in an interference standard of known concentration of B (and containing no A), and ZAF correction parameters for the matrices of both the unknown and the interference standard at It can be shown that:

Reconstructing sea turtle ontogenetic habitat shifts through trace element analysis of bone tissue

2019 ◽  
Vol 608 ◽  
pp. 247-262 ◽  
Author(s):  
MD Ramirez ◽  
JA Miller ◽  
E Parks ◽  
L Avens ◽  
LR Goshe ◽  
...  
Keyword(s):  
Trace Element ◽  
Bone Tissue ◽  
Trace Element Analysis ◽  
Sea Turtle ◽  
Element Analysis ◽  
Ontogenetic Habitat Shifts

Method of Detecting Trace Metal Contamination in Thick-Film SOI Device

2005 ◽  
Author(s):  
Yasunori Goto ◽  
Hiroomi Eguchi ◽  
Masaru Iida
Keyword(s):  
Trace Metal ◽  
Thick Film ◽  
Metal Contamination ◽  
Semiconductor Device ◽  
Trace Element Analysis ◽  
Silicon On Insulator ◽  
Element Analysis ◽  
Trace Metal Contamination ◽  
Trace Metal Elements ◽  
Output Characteristics

Abstract In the automotive IC using thick-film silicon on insulator (SOI) semiconductor device, if the gettering capability of a SOI wafer is inadequate, electrical characteristics degradation by metal contamination arises and the yield falls. At this time, an automotive IC was made experimentally for evaluation of the gettering capability as one of the purposes. In this IC, one of the output characteristics varied from the standard, therefore failure analysis was performed, which found trace metal elements as one of the causes. By making full use of 3D perspective, it is possible to fabricate a site-specific sample into 0.1 micrometre in thickness without missing a failure point that has very minute quantities of contaminant in a semiconductor device. Using energy dispersive X-ray, it is possible to detect trace metal contamination at levels 1E12 atoms per sq cm. that are conventionally detected only by trace element analysis.

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