In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 19, No. 22 ( 2019-11-25), p. 14173-14193
Abstract:
Abstract. Peat fuels representing four biomes of boreal (western Russia and Siberia),
temperate (northern Alaska, USA), subtropical (northern and southern
Florida, USA), and tropical (Borneo, Malaysia) regions were burned in a
laboratory chamber to determine gas and particle emission factors (EFs).
Tests with 25 % fuel moisture were conducted with predominant smoldering
combustion conditions (average modified combustion efficiency (MCE) =0.82±0.08). Average fuel-based EFCO2 (carbon dioxide) are highest
(1400 ± 38 g kg−1) and lowest (1073 ± 63 g kg−1) for
the Alaskan and Russian peats, respectively. EFCO (carbon monoxide) and
EFCH4 (methane) are ∼12 %–15 % and ∼0.3 %–0.9 % of EFCO2, in the range of 157–171 and 3–10 g kg−1, respectively. EFs for nitrogen species are at the same magnitude
as EFCH4, with an average of 5.6 ± 4.8 and 4.7 ± 3.1 g kg−1 for EFNH3 (ammonia) and EFHCN (hydrogen cyanide); 1.9±1.1 g kg−1 for EFNOx (nitrogen oxides); and 2.4±1.4 and 2.0 ± 0.7 g kg−1 for EFNOy (total reactive
nitrogen) and EFN2O (nitrous oxide). An oxidation flow reactor (OFR) was used to simulate atmospheric aging times
of ∼2 and ∼7 d to compare fresh (upstream)
and aged (downstream) emissions. Filter-based EFPM2.5 varied by
〉 4-fold (14–61 g kg−1) without appreciable changes between
fresh and aged emissions. The majority of EFPM2.5 consists of EFOC
(organic carbon), with EFOC ∕ EFPM2.5 ratios in the range of 52 %–98 % for fresh emissions and ∼14 %–23 % degradation after
aging. Reductions of EFOC (∼7–9 g kg−1) after aging
are most apparent for boreal peats, with the largest degradation in low-temperature OC1 that evolves at 〈 140 ∘C, indicating the
loss of high-vapor-pressure semivolatile organic compounds upon aging. The
highest EFLevoglucosan is found for Russian peat (∼16 g kg−1), with ∼35 %–50 % degradation after aging. EFs for
water-soluble OC (EFWSOC) account for ∼20 %–62 % of
fresh EFOC. The majority (〉 95 %) of the total emitted carbon is in the
gas phase, with 54 %–75 % CO2, followed by 8 %–30 % CO. Nitrogen in
the measured species explains 24 %–52 % of the consumed fuel nitrogen, with an average of 35 ± 11 %, consistent with past studies that report
∼1/3 to 2∕3 of the fuel nitrogen measured in biomass
smoke. The majority (〉 99 %) of the total emitted nitrogen is
in the gas phase, with an average of 16.7 % as NH3 and 9.5 % as
HCN. N2O and NOy constituted 5.7 % and 2.9 % of consumed
fuel nitrogen. EFs from this study can be used to refine current emission
inventories.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-19-14173-2019
DOI:
10.5194/acp-19-14173-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
Permalink