emission factors and evolution of so2 measured from ... · emission factors and evolution of so...
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Emission factors and evolution of SO2 measured from biomass burning during FIREX-AQPamela S. Rickly1,2, Hongyu Guo1,3, Benjamin A Nault1,3, Pedro Campuzano-Jost1,3, Jose L. Jimenez1,3, Andrew Rollins2
1Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA2Chemical Sciences Laboratory, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO 80305, USA
3Department of Chemistry, University of Colorado, Boulder, CO 80309, USA
INTRODUCTION• Sulfate aerosols cool the Earth’s surface• They produce harmful effects for human health• Sulfate is formed through the oxidation of SO2
• Biomass burning emits large concentrations of SO2
• Large uncertainty in SO2 emission factors have been reported
• Conversion mechanism of SO2 to sulfate remains uncertain creating underprediction of sulfate in atmospheric models by up to a factor of two (Wang et al., 2016; Shao et al., 2019; Wang et al., 2014).
EMISSION FACTORS• Emission factor data during flaming conditions
agree well with compiled field values when combined based on environmental characteristics.
• Large variation in temperate forest data suggests a more limited definition may be necessary.
• Overall, difference between flaming and smoldering emissions is unclear with flaming stage = 0.62 ± 0.27 g kg-1 and smoldering stage = 0.56 ± 0.26 g kg-1.
MODELLING• F0AM mechanism developed with the inclusion of
O3, H2O2, NO2, and HCHO aqueous phase S(IV) oxidation.
• Produces S(IV) pH dependence • Produces pH dependence of sulfate production as
previously observed for each oxidant• Reproduces downwind SO2 trends within 10%
and sulfate trends within 15% for the Williams Flats fire.
• O3 + SO32- is the largest contributor to sulfateproduction.
• Laser-induced fluorescence used to measure SO2
• Sulfate measurements from the aerosol mass spectrometry group
• DC-8 platform used for measurements of biomass burning smoke plumes
• F0AM 0-D box model used for modelling conversion of SO2 to sulfate in a more neutral environment (pH 7) compared to urban (pH <3)
ReferencesAndreae, M. O.: Emission of trace gases and aerosols from biomass burning – an updated assessment, Atmos. Chem. Phys., 19, 8523–8546, https://doi.org/10.5194/acp-19-8523-2019, 2019.Wang, G., Zhang, R., Gomez, M. E., Yang, L., Zamora, M. L., Hu, M., Lin, Y., Peng, J., Guo, S., Meng, J., Li, J., Cheng, C., Hu, T., Ren, Y., Wang, Y., Gao, J., Cao, J., An, Z., Zhou, W., Li, G., Wang, J., Tian, P., Marrero-Ortiz, W., Secrest, J., Du, Z., Zheng, J., Shang, D., Zeng, L., Shao, M., Wang, W., Huang, Y., Wang, Y., Zhu, Y., Li, Y., Hu, J., Pan, B., Cai, L., Cheng, Y., Ji, Y., Zhang, F., Rosenfeld, D., Liss, P. S., Duce, R. A., Kolb, C. E., and Molina, M. J.: Persistent sulfate formation from London Fog to Chinese haze, PNAS, 113 (48) 13630-13635, https://doi.org/10.1073/pnas.1616540113Shao, J., Chen, Q., Wang, Y., Lu, X., He, P., Sun, Y., Shah, V., Martin, R. V., Philip, S., Song, S., Zhao, Y., Xie, Z., Zhang, L., and Alexander, B.: Heterogeneous sulfate aerosol formation mechanisms during wintertime Chinese haze events: air quality model assessment using observations of sulfate oxygen isotopes in Beijing, Atmos. Chem. Phys., 19, 6107–6123, https://doi.org/10.5194/acp-19-6107-2019, 2019.Wang, Y., Q. Q. Zhang, J. Jiang, W. Zhou, B. Wang, K. He, F. Duan, Q. Zhang, S. Philip, and Y. Xie (2014), Enhanced sulfate formation during China’s severe winter haze episode in January 2013 missing from current models, J. Geophys. Res. Atmos., 119, 10,425–10,440, doi:10.1002/2013JD021426.Photo by https://unsplash.com/photos/j7wXfhojXtk
METHODS
100
80
60
40
20
0
ppb
76543210Plume age (hr)
SO2 measured SO4 measured SO2 fit SO4 fit SO2 model SO4 model
3 Aug 2019
2.0
1.5
1.0
0.5
0.0
Emiss
ion
Fact
ors
Rela
tive
to Δ
CO +
ΔCO
2
Shad
y fu
el
Piño
n Ju
nipe
r
Tall g
rass
/Ced
ar
Tim
ber/U
nder
stor
y
Tim
ber/S
lash
Blac
kwat
er fu
el
Agric
ultu
re
Savanna/Grasslands
TemperateForest
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
101
102
103
SO4 r
ate
(hr-1
)
6420pH
H2O2 O3 NO2