In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 12 ( 2023-06-21), p. 6879-6896
Abstract:
Abstract. New particle formation (NPF) and growth are a major source of atmospheric
fine particles. In polluted urban environments, NPF events are frequently
observed with characteristics distinct from those in clean environments.
Here we simulate NPF events in urban Beijing with a discrete-sectional model that couples cluster dynamics and multicomponent particle growth. In the model, new particles are formed by sulfuric acid–dimethylamine nucleation, while particle growth is driven by particle coagulation and the condensation
of sulfuric acid, its clusters, and oxygenated organic molecules (OOMs). A
variable simulation domain in the particle size space is applied to isolate
newly formed particles from preexisting ones, which allows us to focus on
new particle formation and growth rather than the evolution of particles of
non-NPF origin. The simulation yields a rich set of information including
the time-dependent NPF rates, the cluster concentrations, the particle size
distributions, and the time- and size-specific particle chemical
compositions. These can be compared with the field observations to
comprehensively assess the simulation–observation agreement. Sensitivity
analysis with the model further quantifies how metrics of NPF events (e.g.,
particle survival probability) respond to model input variations and serves
as a diagnostic tool to pinpoint the key parameter that leads to
simulation–observation discrepancies. Seven typical NPF events in urban
Beijing were analyzed. We found that with the observed gaseous precursor
concentrations and coagulation sink as model inputs, the simulations roughly captured the evolution of the observed particle size distributions; however,
the simulated particle growth rate was insufficient to yield the observed
particle number concentrations, survival probability, and mode diameter.
With the aid of sensitivity analysis, we identified under-detected OOMs as a
likely cause for the discrepancy, and the agreement between the simulation
and the observation was improved after we modulated particle growth rates in the simulation by adjusting the abundance of OOMs.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-6879-2023
DOI:
10.5194/acp-23-6879-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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