Charging and coagulation of radioactive and nonradioactive particles in the atmosphere
Charging and coagulation influence one another and impact the particle charge and size distributions in the atmosphere. However, few investigations to date have focused on the coagulation kinetics of atmospheric particles accumulating charge. This study presents three approaches to include mutual...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/16/3449/2016/acp-16-3449-2016.pdf |
| Summary: | Charging and coagulation influence one another and impact the particle
charge and size distributions in the atmosphere. However, few investigations
to date have focused on the coagulation kinetics of atmospheric particles
accumulating charge. This study presents three approaches to include mutual
effects of charging and coagulation on the microphysical evolution of
atmospheric particles such as radioactive particles. The first approach
employs ion balance, charge balance, and a bivariate population balance
model (PBM) to comprehensively calculate both charge accumulation and
coagulation rates of particles. The second approach involves a much simpler
description of charging, and uses a monovariate PBM and subsequent effects
of charge on particle coagulation. The third approach is further simplified
assuming that particles instantaneously reach their steady-state charge
distributions. It is found that compared to the other two approaches, the
first approach can accurately predict time-dependent changes in the size and
charge distributions of particles over a wide size range covering from the
free molecule to continuum regimes. The other two approaches can reliably
predict both charge accumulation and coagulation rates for particles larger
than about 0.04 micrometers and atmospherically relevant conditions. These
approaches are applied to investigate coagulation kinetics of particles
accumulating charge in a radioactive neutralizer, the urban atmosphere, and
an atmospheric system containing radioactive particles. Limitations of the
approaches are discussed. |
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| ISSN: | 1680-7316 1680-7324 |