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Accelerator-Based Chemical and Elemental Analysis of Atmospheric Aerosols

Mentes, Besim (1999)
Abstract
Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is... (More)
Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is forbidden at certain times when the meteorological conditions are unfavourable. Aerosols play an important role in the climate, and may have both direct and indirect effect which cause cooling of the planet surface, in contrast to the so-called greenhouse gases.



During this work a technique for chemical and elemental analysis of atmospheric aerosols and an elemental analysis methodology for upper tropospheric aerosols have been developed. The elemental analysis is performed by the ion beam analysis (IBA) techniques, PIXE (elements heavier than Al), PESA (C, N and O), cPESA (H) and pNRA (Mg and Na). The chemical speciation of atmospheric aerosols is obtained by ion beam thermography (IBT). During thermography the sample temperature is stepwise increased and the IBA techniques are used to continuously monitor the elemental concentration. A thermogram is obtained for each element. The vaporisation of the compounds in the sample appears as a concentration decrease in the thermograms at characteristic vaporisation temperatures (CVTs). Different aspects of IBT have been examined in Paper I to IV. The features of IBT are: almost total elemental speciation of the aerosol mass, chemical speciation of the inorganic compounds, carbon content obtained as volatile and non-volatile fractions, analysis of acidic aerosols is possible, aerosols can be size-fractionated using a cascade impactor as collection device, total analysis time for a sample is around 45 min, the sample mass load is from around 1 to 30 ug/cm<sup>2</sup>.



An intercomparison of IBT and ion chromatography (IC) when a DMPS system was used as a reference instrument has been performed (Paper IV). Ions of K, Na, SO<sub>4</sub>, NO<sub>3</sub> and NH<sub>4</sub> were determined and quantified by both IBT and IC. The intercomparison showed that the procedure used in IBT does not suffer from any selective losses, especially not from the NO<sub>3</sub> and NH<sub>4</sub> compounds, which exhibit an appreciable interaction with the gas phase as NH<sub>3</sub> and HNO<sub>3</sub>.



An impactor-based aerosol sampler for upper tropospheric conditions has been developed (Paper V). Despite the low aerosol concentration at that altitude the sulphur concentration can be measured, with a detection limit of 1 ng/m<sup>3</sup> for one hour sampling by optimising parameters in the use of PIXE analysis. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Dr Cohen, David D., ANSTO, Australia
publishing date
type
Thesis
publication status
published
subject
keywords
elemental analysis, chemical speciation, ammonium bisulphate, ammonium sulphate, sulphuric acid, ammonium chloride, Fysicumarkivet A:1999:Mentes, ammonium nitrate, sodium sulphate, volatile carbon, non-volatile carbon, Kärnfysik Fysicumarkivet A:1999:Mentes, Nuclear physics, Ion beam analysis (IBA), thermography, atmosphere, aerosols
pages
118 pages
publisher
Division of Nuclear Physics, P. O. Box 118, SE-221 00 Lund, Sweden
defense location
"sal B" Physics Institute, Lund
defense date
1999-12-10 10:15
external identifiers
  • other:ISRN: LUTFD2/(TFKF-1023)/1-118/(1999)
ISBN
91-628-3776-1
language
English
LU publication?
no
id
2bc4a647-2152-46fa-9623-1de9b07e8c1a (old id 40144)
date added to LUP
2007-08-01 14:40:35
date last changed
2016-09-19 08:45:02
@phdthesis{2bc4a647-2152-46fa-9623-1de9b07e8c1a,
  abstract     = {Aerosol particles have always been present in the atmosphere, arising from natural sources. But it was not until recently when emissions from anthropogenic (man made) sources began to dominate, that atmospheric aerosols came into focus and the aerosol science in the environmental perspective started to grow. These sources emit or produce particles with different elemental and chemical compositions, as well as different sizes of the individual aerosols. The effects of increased pollution of the atmosphere are many, and have different time scales. One of the effects known today is acid rain, which causes problems for vegetation. Pollution is also a direct human health risk, in many cities where traffic driven by combustion engines is forbidden at certain times when the meteorological conditions are unfavourable. Aerosols play an important role in the climate, and may have both direct and indirect effect which cause cooling of the planet surface, in contrast to the so-called greenhouse gases.<br/><br>
<br/><br>
During this work a technique for chemical and elemental analysis of atmospheric aerosols and an elemental analysis methodology for upper tropospheric aerosols have been developed. The elemental analysis is performed by the ion beam analysis (IBA) techniques, PIXE (elements heavier than Al), PESA (C, N and O), cPESA (H) and pNRA (Mg and Na). The chemical speciation of atmospheric aerosols is obtained by ion beam thermography (IBT). During thermography the sample temperature is stepwise increased and the IBA techniques are used to continuously monitor the elemental concentration. A thermogram is obtained for each element. The vaporisation of the compounds in the sample appears as a concentration decrease in the thermograms at characteristic vaporisation temperatures (CVTs). Different aspects of IBT have been examined in Paper I to IV. The features of IBT are: almost total elemental speciation of the aerosol mass, chemical speciation of the inorganic compounds, carbon content obtained as volatile and non-volatile fractions, analysis of acidic aerosols is possible, aerosols can be size-fractionated using a cascade impactor as collection device, total analysis time for a sample is around 45 min, the sample mass load is from around 1 to 30 ug/cm&lt;sup&gt;2&lt;/sup&gt;.<br/><br>
<br/><br>
An intercomparison of IBT and ion chromatography (IC) when a DMPS system was used as a reference instrument has been performed (Paper IV). Ions of K, Na, SO&lt;sub&gt;4&lt;/sub&gt;, NO&lt;sub&gt;3&lt;/sub&gt; and NH&lt;sub&gt;4&lt;/sub&gt; were determined and quantified by both IBT and IC. The intercomparison showed that the procedure used in IBT does not suffer from any selective losses, especially not from the NO&lt;sub&gt;3&lt;/sub&gt; and NH&lt;sub&gt;4&lt;/sub&gt; compounds, which exhibit an appreciable interaction with the gas phase as NH&lt;sub&gt;3&lt;/sub&gt; and HNO&lt;sub&gt;3&lt;/sub&gt;.<br/><br>
<br/><br>
An impactor-based aerosol sampler for upper tropospheric conditions has been developed (Paper V). Despite the low aerosol concentration at that altitude the sulphur concentration can be measured, with a detection limit of 1 ng/m&lt;sup&gt;3&lt;/sup&gt; for one hour sampling by optimising parameters in the use of PIXE analysis.},
  author       = {Mentes, Besim},
  isbn         = {91-628-3776-1},
  keyword      = {elemental analysis,chemical speciation,ammonium bisulphate,ammonium sulphate,sulphuric acid,ammonium chloride,Fysicumarkivet A:1999:Mentes,ammonium nitrate,sodium sulphate,volatile carbon,non-volatile carbon,Kärnfysik Fysicumarkivet A:1999:Mentes,Nuclear physics,Ion beam analysis (IBA),thermography,atmosphere,aerosols},
  language     = {eng},
  pages        = {118},
  publisher    = {Division of Nuclear Physics, P. O. Box 118, SE-221 00 Lund, Sweden},
  title        = {Accelerator-Based Chemical and Elemental Analysis of Atmospheric Aerosols},
  year         = {1999},
}