both POA and SOA. This technology splits the
organic aerosol into three generic types – an oxygenated organic aerosol (OOA), a hydrogenated
fossil-fuel-derived organic aerosol (HOA), and a
biomass burning organic aerosol (BBOA). OOA
is characterized by its highly oxidized state with
atomic O:C ratios between 0.25 and 1 and can be
further categorized into two subgroups based on
volatility and O:C ratio. Low-volatility OOA
(~C 8 O 5.5 H 10 ) has a high O:C ratio and is frequently correlated to other secondary species
such as sulfate aerosol and is consistent with an
aged aerosol. Semivolatile OOA (~C 8 O 3 H 10 ) has
a lower O:C ratio and is better correlated with
other semivolatile species such as nitrates and is
consistent with a partially photochemically aged
aerosol.
A compilation [41] of measurements of HOA
and OOA types, along with major inorganic species, at different urban, urban downwind, and
remote rural locations, is shown in Fig. 6. What
is clearly evident from the suite of measurements
is that organic matter comprises a significant
fraction of the aerosol mass at all locations; however, the further from pollution sources, the more
oxygenated the organic aerosol is (i.e., the ratio
of OOA/HOA increases) and the more aged, or
distant from pollution sources, the higher fraction of OOA is low-volatility OOA. This study
also reports the evolution of the Mexico City
pollution plume within which there is intense
SOA formation. They found that near the plume
source region, semivolatile OOA dominated the
organic aerosol signal; however, as the plume
advected and aged downwind, the fraction of
low-volatility OOA and the O:C ratio increased.
Laboratory studies on the evolution of biogenic
SOA (from a-pinene oxidation), biomass burning smoke, and the POA surrogate squalane also
exhibit similar aging patterns as in the reported
0.8
0.7
0.6
0.5
0.4
HC-C=O / sum aliphatics
0.3
0.2
0.1
0
0 0.1 0.2 0.3 0.4 0.5
HC-O/sum aliphatics
0.6 0.7 0.8 0.9 1
0.9
1
levoglucosan
succinic acid
adipic acid
pinonic acid
glutaric acid
nonanoic acid
samples
0.60
0.55
0.50
0.45
0.3
0.2
0.1
0.40
0.35
0.30
0.00
0.10
0.20
0.30
0.40
HC-C=O / sum aliphatics
Aromatic/
aliphatic
HC-O/sum aliphatics
Po Valley FA/WI
Po Valley SP/SU
Mt Cimone
Brazil semi-clean
ACE-Asia SP
Hyytiala polluted
Singapore
UK SU urban
UK SU coastal
Marine
OA
SOA
BB
6
0
%
5
0
%
8 0 %
7 0 %
b
a
Aerosol in Global
Atmosphere, Fig. 5 (a)
Functional group
distributions of standards of
water-soluble organic
compounds. The area
including the composition
of the real atmospheric
samples is also indicated.
(b) Functional group
distribution of WSOCs
samples characteristic of
specific aerosol sources.
Diagonal lines represent the
percentage fraction of total
oxygenated groups (H–C–
O + HC–C¼O). (Copyright
American Chemical Society
2007. Reprinted from [34])
250
Aerosol in Global Atmosphere
organic aerosol into three generic types – an oxygenated organic aerosol (OOA), a hydrogenated
fossil-fuel-derived organic aerosol (HOA), and a
biomass burning organic aerosol (BBOA). OOA
is characterized by its highly oxidized state with
atomic O:C ratios between 0.25 and 1 and can be
further categorized into two subgroups based on
volatility and O:C ratio. Low-volatility OOA
(~C 8 O 5.5 H 10 ) has a high O:C ratio and is frequently correlated to other secondary species
such as sulfate aerosol and is consistent with an
aged aerosol. Semivolatile OOA (~C 8 O 3 H 10 ) has
a lower O:C ratio and is better correlated with
other semivolatile species such as nitrates and is
consistent with a partially photochemically aged
aerosol.
A compilation [41] of measurements of HOA
and OOA types, along with major inorganic species, at different urban, urban downwind, and
remote rural locations, is shown in Fig. 6. What
is clearly evident from the suite of measurements
is that organic matter comprises a significant
fraction of the aerosol mass at all locations; however, the further from pollution sources, the more
oxygenated the organic aerosol is (i.e., the ratio
of OOA/HOA increases) and the more aged, or
distant from pollution sources, the higher fraction of OOA is low-volatility OOA. This study
also reports the evolution of the Mexico City
pollution plume within which there is intense
SOA formation. They found that near the plume
source region, semivolatile OOA dominated the
organic aerosol signal; however, as the plume
advected and aged downwind, the fraction of
low-volatility OOA and the O:C ratio increased.
Laboratory studies on the evolution of biogenic
SOA (from a-pinene oxidation), biomass burning smoke, and the POA surrogate squalane also
exhibit similar aging patterns as in the reported
0.8
0.7
0.6
0.5
0.4
HC-C=O / sum aliphatics
0.3
0.2
0.1
0
0 0.1 0.2 0.3 0.4 0.5
HC-O/sum aliphatics
0.6 0.7 0.8 0.9 1
0.9
1
levoglucosan
succinic acid
adipic acid
pinonic acid
glutaric acid
nonanoic acid
samples
0.60
0.55
0.50
0.45
0.3
0.2
0.1
0.40
0.35
0.30
0.00
0.10
0.20
0.30
0.40
HC-C=O / sum aliphatics
Aromatic/
aliphatic
HC-O/sum aliphatics
Po Valley FA/WI
Po Valley SP/SU
Mt Cimone
Brazil semi-clean
ACE-Asia SP
Hyytiala polluted
Singapore
UK SU urban
UK SU coastal
Marine
OA
SOA
BB
6
0
%
5
0
%
8 0 %
7 0 %
b
a
Aerosol in Global
Atmosphere, Fig. 5 (a)
Functional group
distributions of standards of
water-soluble organic
compounds. The area
including the composition
of the real atmospheric
samples is also indicated.
(b) Functional group
distribution of WSOCs
samples characteristic of
specific aerosol sources.
Diagonal lines represent the
percentage fraction of total
oxygenated groups (H–C–
O + HC–C¼O). (Copyright
American Chemical Society
2007. Reprinted from [34])
250
Aerosol in Global Atmosphere