384
J. Jiang et al.
modified VBS scheme improved the model performance on OA simulation during the whole period by reducing the bias between model and measurements by
up to 52%. The OA concentrations were dominated by biomass burning in winter,
while biogenic emissions were the main sources in summer. The contribution of
road traffic was relatively lower compared to studies in the USA. The contribution
of new gasoline and diesel vehicles (after Euro IV emission standards or equipped
with diesel particle filters) to the total OA was negligible.
61.1 Introduction
Organic aerosols (OA) contribute to 20–90% of atmospheric fine particulate matter
pollution, which exerts significant impacts on human health and climate change.
Among the numerous components of OA, secondary organic aerosol (SOA) generated from oxidation of organic gases is proved to be dominant [1]. Traditional
chemical transport models (CTMs) tend to underestimate SOA substantially due to
its numerous sources, composition and chemical-physical properties [2]. One of the
most important reasons is the potentially high but unaccounted for contribution of
semi-volatile organics (SVOCs) and intermediate-volatility organics (IVOCs). To
improve the situation, the volatility basis set (VBS) scheme has been applied in
CTMs like CAMx (Comprehensive Air quality Model with extensions) and CMAQ
(Community Multiscale Air Quality) [3]. The VBS scheme characterizes organic
species as surrogates by their volatilities [4], and therefore better simulate the oxidation of a wide range of organics. Despite its great potential, high uncertainties
still remain. Recent studies found that precursors in traditional models account for
only ~3–27% of the observed SOA from residential wood burning [5]; formation of
SOA from diesel and gasoline vehicles were greatly influenced by temperature and
vehicle condition (with or without diesel particle filter) [6]. Thus, in this study, we
parameterized the regional model CAMx with VBS scheme based on recent findings
from experimental studies, and simulated the contribution of major anthropogenic
and biogenic sources on OA in Europe.
61.2 Method
The regional air quality model CAMx version 6.3 with VBS scheme [7] was used
in this study. The model domain (15° W–35° E, 35° N–70° N) covered Europe with
a horizontal resolution of 0.25° × 0.125°. The whole year of 2011 was modelled.
Organic aerosol formation was estimated by the 1.5-D VBS organic aerosol chemistry/partitioning module [3]. We split the sources of gasoline vehicles (GV) and
diesel vehicles (DV) in standard model to old and new (GO, GN, DO, DN), and the
biomass/biogenic source (BB) to biomass burning (BB) and biogenic (BI). Parameters of yield for GO, GN, DO, DN were adjusted respectively according to chamber
J. Jiang et al.
modified VBS scheme improved the model performance on OA simulation during the whole period by reducing the bias between model and measurements by
up to 52%. The OA concentrations were dominated by biomass burning in winter,
while biogenic emissions were the main sources in summer. The contribution of
road traffic was relatively lower compared to studies in the USA. The contribution
of new gasoline and diesel vehicles (after Euro IV emission standards or equipped
with diesel particle filters) to the total OA was negligible.
61.1 Introduction
Organic aerosols (OA) contribute to 20–90% of atmospheric fine particulate matter
pollution, which exerts significant impacts on human health and climate change.
Among the numerous components of OA, secondary organic aerosol (SOA) generated from oxidation of organic gases is proved to be dominant [1]. Traditional
chemical transport models (CTMs) tend to underestimate SOA substantially due to
its numerous sources, composition and chemical-physical properties [2]. One of the
most important reasons is the potentially high but unaccounted for contribution of
semi-volatile organics (SVOCs) and intermediate-volatility organics (IVOCs). To
improve the situation, the volatility basis set (VBS) scheme has been applied in
CTMs like CAMx (Comprehensive Air quality Model with extensions) and CMAQ
(Community Multiscale Air Quality) [3]. The VBS scheme characterizes organic
species as surrogates by their volatilities [4], and therefore better simulate the oxidation of a wide range of organics. Despite its great potential, high uncertainties
still remain. Recent studies found that precursors in traditional models account for
only ~3–27% of the observed SOA from residential wood burning [5]; formation of
SOA from diesel and gasoline vehicles were greatly influenced by temperature and
vehicle condition (with or without diesel particle filter) [6]. Thus, in this study, we
parameterized the regional model CAMx with VBS scheme based on recent findings
from experimental studies, and simulated the contribution of major anthropogenic
and biogenic sources on OA in Europe.
61.2 Method
The regional air quality model CAMx version 6.3 with VBS scheme [7] was used
in this study. The model domain (15° W–35° E, 35° N–70° N) covered Europe with
a horizontal resolution of 0.25° × 0.125°. The whole year of 2011 was modelled.
Organic aerosol formation was estimated by the 1.5-D VBS organic aerosol chemistry/partitioning module [3]. We split the sources of gasoline vehicles (GV) and
diesel vehicles (DV) in standard model to old and new (GO, GN, DO, DN), and the
biomass/biogenic source (BB) to biomass burning (BB) and biogenic (BI). Parameters of yield for GO, GN, DO, DN were adjusted respectively according to chamber