In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 19, No. 19 ( 2019-10-14), p. 12797-12809
Abstract:
Abstract. Biomass burning is an important source of aerosol and
trace gases to the atmosphere, but how these emissions change chemically
during their lifetimes is not fully understood. As part of the Fire
Influence on Regional and Global Environments Experiment (FIREX 2016), we
investigated the effect of photochemical aging on biomass burning organic
aerosol (BBOA) with a focus on fuels from the western United States.
Emissions were sampled into a small (150 L) environmental chamber and
photochemically aged via the addition of ozone and irradiation by 254 nm
light. While some fraction of species undergoes photolysis, the vast
majority of aging occurs via reaction with OH radicals, with total OH
exposures corresponding to the equivalent of up to 10 d of atmospheric
oxidation. For all fuels burned, large and rapid changes are seen in the
ensemble chemical composition of BBOA, as measured by an aerosol mass
spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for
all aging experiments and continues to grow with increasing OH exposure, but
the magnitude of the SOA formation is highly variable between experiments.
This variability can be explained well by a combination of differences in OH
exposure and the total concentration of non-methane organic gases (NMOGs) in
the chamber before oxidation, as measured by PTR-ToF-MS (r2 values from
0.64 to 0.83). From this relationship, we calculate the fraction of carbon
from biomass burning NMOGs that is converted to SOA as a function of
equivalent atmospheric aging time, with carbon yields ranging from 24±4 % after 6 h to 56±9 % after 4 d.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-19-12797-2019
DOI:
10.5194/acp-19-12797-2019-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2019
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1