CHRACTERIZATION OF PRIMARY ORGANIC AEROSOL OF DOMESTIC WOOD, PEAT,
AND COAL BURNING
C. Lin1, J. OVADNEVAITE1, D. CEBURNIS1, R. HUANG2, C. O’DOWD1
1
School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, National University
of Ireland Galway, University Road, Galway, Republic of Ireland
2
State Key Laboratory of Loess and Quaternary Geology and Key Laboratory of Aerosol Chemistry and
Physics, Institute of Earth Environment, Chinese Academy of Sciences, 710075, Xi’an, China
Keywords: ACSM, WOOD, COAL, PEAT, SOLID FUELS.
INTRODUCTION
Ambient particulate matter (PM) adversely affects human health (Pope et al., 2002) and has a great
influence on climate (O'Dowd et al., 2004). Direct Aerosol Mass Spectrometer (AMS) measurement of
OA from various primary emissions can help understand the MS signatures of different primary OA
sources and thus help the interpretation of AMS MS. To the best of our knowledge, direct ACSM, a
compact version of AMS, measurements and comparison of domestic wood, peat, and coal burning
have not been reported which should get more attention for their significant impacts on air quality in areas
where these fuels are popular, e.g. Ireland and the UK.
METHODS
Wood, peat, and coal were burned in a typical residential stove in Ireland (Scheme 1). Characterization of
PM emitted from burning these samples was conducted using an ACSM. OA was found to be the major
contributor to the total sub-micro non-refractory (NR-PM1) aerosol particles. Unit mass resolution mass
spectral signatures of OA from each fuel type were studied and compared. These directly ACSM
measured reference profiles were used to apportion the ACSM measured ambient OA in Dublin, Ireland to
estimate their relative contribution to air pollution and characterize their emission and formation process
by constraining the profiles with ME-2 when running PMF.
Scheme 1. Schematic of Irish residential solid fuel combustion and ACSM measurement system
RESULTS
Averaged normalized ACSM unit mass resolution (UMR) mass spectra (MS) of OA particles obtained for
dry wood, peat, and coal are shown in Figure 1. All three MS are dominated by CnH2n+1 (29, 43, 57, 71…)
and CnH2n-1 (27, 41, 55, 69…), indicating the large contribution from saturated alkanes, alkenes, and also
possible cycloalkanes in the primary OA emissions from wood, peat, and coal. However, the MS profile
patterns and signals at specific m/z (e.g. m/z 60) of different fuels vary significantly corresponding to the
composition of the fuels. For example, the most prominent ion in wood burning aerosol MS profile is the
signal at m/z (mass to charge ratio) 29, followed by m/z 43 while m/z 43 is the most abundant ion in peat
emissions, followed by m/z 29. In contrast, m/z 43 and m/z 41 are the most abundant ions in coal emissions
MS. In addition, there was a higher contribution from heavier ions (in the range of m/z > 120) in the coal
emission spectra most likely from PAH emissions if compared to the peat and wood spectra.
Relative Intensity
0.10
0.08
0.06
0.04
0.02
0.00
0.10
0.08
0.06
0.04
0.02
0.00
29
43
15
57
55
27
18
41
20
40
29
20
0.10
0.08
0.06
0.04
0.02
0.00
20
100
120
140
(B) Peat briquettes (PB)
41
55
40
57 67
91
77
60
43
27
137
115
91
80
55 57
60
40
29
77
69 71
27
18
73
60
43
41
15
(A) Dry wood (DW)
60 69
80
100
120
(C) Smoky coal (SC)
69 71
77
60
140
91
115
80
100
128
120
140
200
160
120
80
50
40
30
20
10
0
:00
12
0
0:0
30
:00
12
0
0:0
20
1/2
UTC Time
1/2
:00
12
0
0:0
10
1/2
:00
12
0
0:0
00
1/2
12
0
0:0
90
1/1
2:0
81
1/1
:00
NH4
Org
SO4
NO3
Chl
0
Loadings (ug/m3)
Figure 1. Normalized mass spectra of organics from the combustion of (A) dry wood; (B) peat briquettes;
(C) smoky coal.
Figure 2. Time series of ACSM, aerosol chemical speciation monitor, measured non-refractory particulate
sub-micron matter species (NR-PM1, i.e. organics, sulfate, nitrate, ammonium, and chloride) before and
after the high pollution event on 22nd Jan, 2017 in Dublin, Ireland. Relative contribution of ACSM
measured species emphasize the importance of organic which accounts for 68% of total NR-PM1. Nitrate
accounts for 17% of total NR-PM1, and was elevated throughout the pollution events indicating a regional
source.
Real time measurements of NR-PM1 capture pollution events with peak concentration of 207 μg/m3
occurring at around 21:00 at UCD, Dublin, an urban background monitoring site (Figure 2). The night
time pollution corresponds to domestic heating activities. As possible source candidates of OA, wood,
peat, and coal, as well as oil burning emission were evaluated using PMF source apportionment technique
to assess their contribution to the extreme air pollution events. For source apportionment of OA, we
take advantage of ME-2 which can direct the PMF analysis to environmentally reasonable
solutions by constraining the priori ACSM derived souce profiles of peat, coal, and wood, as well
as oil (HOA) from Crippa et al. (2013). A small a-value of 0.1 (i.e. 10% variation in profile) was
applied due to the fact that most primary OA were freshly-emitted, with peak concentrations
occuring at the early nighttime and thus should have small varation from the ACSM derived
fingerprints (Figure 3). Due to the lack of possible tracer marker for each type of domestic fuel
combustions, the best a-value will be further investigated.
0.08
Oil, a-value: 0.1
0.04
Relative Intensity
0.00
0.08
Peat, a-value: 0.1
0.04
0.00
0.08
Coal, a-value: 0.1
0.04
0.00
0.12
0.08
0.04
0.00
0.24
Wood, a-value: 0.1
0.16
0.08
0.00
OOA, unconstrained
20
30
40
50
60
70
80
90
100
m/z
Figure 3. Factor profiles (mass spectra) of 5-factor ME-2 solution.
Figure 4. Time series of ME-2 resolved factors (i.e. oil, peat, coal, wood and OOA), and relative
contribution of each factor to total OA.
ACSM-PMF results show the importance of solid fuel burning during the pollution events, with the
combined contribution of coal, peat, and wood of 78% to the total OA (Figure 4). Among solid fuels, peat
was the dominant OA factors and peaked at around 21:00 in the evening, accounting for 41% of total OA
which is consistent with the popularity of peat and International Energy Agency (2013) data that shows
peat was mostly consumed solid fuel in Ireland. The contribution of coal was only around 8%, which is
consistent with the ban on sales of smoky coal in Dublin. OOA was relatively stable compared to primary
OA with elevated concentration during early night which might from the condensation of volatile organic
matter. OOA is prevalent throughout the day while all primary factors fell to background levels during the
day. The behavior of OOA indicates its formation process needs favorable conditions such as time and
temperature. Back trajectory of air masses shows OOA might come from mainland Europe.
ACKNOWLEDGEMENTS
This work was supported by EPA of Ireland and Chinese Scholarship Committee (CSC).
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Crippa, M., Decarlo, P. F., Slowik, et al. (2013). Wintertime aerosol chemical composition and source apportionment
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