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Process based Modelling of Chemical and Physical Aerosol Properties Relevant for Climate and Health

Roldin, Pontus LU (2013)
Abstract
Atmospheric aerosol particles have substantial influence on climate and air quality. However, the anthropogenic influence on the atmospheric aerosol is still poorly known. This limits the understanding of past and future climate changes. Additionally, both epidemiological and toxicological studies indicate adverse health effects of inhaled aerosol particles. In order to study the effect of atmospheric processes on the particle properties relevant for climate and health, two models were developed and implemented.

The first is a 2D-Lagrangian model for Aerosol Dynamics, gas phase CHEMistry and radiative transfer (ADCHEM), which treats the dispersion in the vertical and horizontal direction perpendicular to air mass trajectories. The... (More)
Atmospheric aerosol particles have substantial influence on climate and air quality. However, the anthropogenic influence on the atmospheric aerosol is still poorly known. This limits the understanding of past and future climate changes. Additionally, both epidemiological and toxicological studies indicate adverse health effects of inhaled aerosol particles. In order to study the effect of atmospheric processes on the particle properties relevant for climate and health, two models were developed and implemented.

The first is a 2D-Lagrangian model for Aerosol Dynamics, gas phase CHEMistry and radiative transfer (ADCHEM), which treats the dispersion in the vertical and horizontal direction perpendicular to air mass trajectories. The second model is a kinetic multilayer model for Aerosol Dynamics, gas and particle phase chemistry in laboratory CHAMber environments (ADCHAM). With ADCHAM it is possible to study process based formation and evaporation of secondary organic aerosol particles, and mass transfer limitations and reactions within the particle phase.

ADCHEM was used to quantify the anthropogenic influence from the city of Malmö (280 000 inhabitants) in southern Sweden. In Malmö and a few tens of kilometres downwind, the primary particle emissions have a large influence on the particle number concentration. However, more than 2 hours downwind Malmö, the anthropogenic particle mass contribution is dominated by secondary ammonium nitrate. To quantify the direct and indirect climate impact of urban aerosol emissions, the secondary aerosol formation which changes the optical and hygroscopic properties of the primary soot particles, needs to be addressed in future measurements and process modelling.

ADCHAM was used to simulate different laboratory chamber experiment, with focus on potential influential but poorly known processes for secondary organic aerosol properties, formation and evaporation rates in the atmosphere (i.e. oligomerization, organic salt formation, salting-out effects, oxidation of organic compounds in the particle phase and mass transfer limitations in the particle phase). The model results reveal that formation of small amounts of low-volatile and long lived oligomers, which accumulate in the particle surface layers, can effectively prevent the evaporation of more volatile compounds. This can significantly prolong the lifetime of SOA in the atmosphere. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Korhonen, Hannele, Finnish Meteorological Institute, Kuopio Unit, Finland.
organization
publishing date
type
Thesis
publication status
published
subject
keywords
gas phase chemistry, aerosol dynamics, aerosol particles, climate, kinetic multilayer model, Fysicumarkivet A:2013:Roldin
pages
274 pages
publisher
Division of Nuclear Physics, Department of Physics Box 118, SE-221 00 Lund
defense location
Lecture hall Rydbergsalen, Department of Physics, Sölvegatan 14, Lund University Faculty of Engineering
defense date
2013-05-31 13:15
ISBN
978-91-7473-535-2
project
MERGE
language
English
LU publication?
yes
id
0974aecc-e66e-4ea9-a11c-3a6acdecb38d (old id 3735294)
date added to LUP
2013-05-08 11:07:22
date last changed
2016-09-19 08:45:09
@misc{0974aecc-e66e-4ea9-a11c-3a6acdecb38d,
  abstract     = {Atmospheric aerosol particles have substantial influence on climate and air quality. However, the anthropogenic influence on the atmospheric aerosol is still poorly known. This limits the understanding of past and future climate changes. Additionally, both epidemiological and toxicological studies indicate adverse health effects of inhaled aerosol particles. In order to study the effect of atmospheric processes on the particle properties relevant for climate and health, two models were developed and implemented.<br/><br>
The first is a 2D-Lagrangian model for Aerosol Dynamics, gas phase CHEMistry and radiative transfer (ADCHEM), which treats the dispersion in the vertical and horizontal direction perpendicular to air mass trajectories. The second model is a kinetic multilayer model for Aerosol Dynamics, gas and particle phase chemistry in laboratory CHAMber environments (ADCHAM). With ADCHAM it is possible to study process based formation and evaporation of secondary organic aerosol particles, and mass transfer limitations and reactions within the particle phase. <br/><br>
ADCHEM was used to quantify the anthropogenic influence from the city of Malmö (280 000 inhabitants) in southern Sweden. In Malmö and a few tens of kilometres downwind, the primary particle emissions have a large influence on the particle number concentration. However, more than 2 hours downwind Malmö, the anthropogenic particle mass contribution is dominated by secondary ammonium nitrate. To quantify the direct and indirect climate impact of urban aerosol emissions, the secondary aerosol formation which changes the optical and hygroscopic properties of the primary soot particles, needs to be addressed in future measurements and process modelling. <br/><br>
ADCHAM was used to simulate different laboratory chamber experiment, with focus on potential influential but poorly known processes for secondary organic aerosol properties, formation and evaporation rates in the atmosphere (i.e. oligomerization, organic salt formation, salting-out effects, oxidation of organic compounds in the particle phase and mass transfer limitations in the particle phase). The model results reveal that formation of small amounts of low-volatile and long lived oligomers, which accumulate in the particle surface layers, can effectively prevent the evaporation of more volatile compounds. This can significantly prolong the lifetime of SOA in the atmosphere.},
  author       = {Roldin, Pontus},
  isbn         = {978-91-7473-535-2},
  keyword      = {gas phase chemistry,aerosol dynamics,aerosol particles,climate,kinetic multilayer model,Fysicumarkivet A:2013:Roldin},
  language     = {eng},
  pages        = {274},
  publisher    = {ARRAY(0x98b4440)},
  title        = {Process based Modelling of Chemical and Physical Aerosol Properties Relevant for Climate and Health},
  year         = {2013},
}