Impact of wildfires on size-resolved aerosol composition at a coastal California site
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Authors
Jonsson, H.H.
Maudlin, L.C.
Wang, Z.
Sorooshian, A.
Subjects
MOUDI
Biomass burning
Marine
Aerosol
Composition
Soil
Cloud water
Biomass burning
Marine
Aerosol
Composition
Soil
Cloud water
Advisors
Date of Issue
2015-08-14
Date
August 14, 2015
Publisher
Elsevier Ltd.
Language
Abstract
Size-resolved aerosol composition measurements were conducted at a coastal site in central California
during the Nucleation in California Experiment (NiCE) between July and August of 2013. The site is just
east of ship and marine emission sources and is also influenced by continental pollution and wildfires,
such as those near the CaliforniaeOregon border which occurred near the end of NiCE. Two micro-orifice
uniform deposit impactors (MOUDIs) were used, and water-soluble and elemental compositions were
measured. The five most abundant water-soluble species (in decreasing order) were chloride, sodium,
non-sea salt (nss) sulfate, ammonium, and nitrate. During wildfire periods, nss K mass concentrations
were not enhanced as strongly as other species in the sub-micrometer stages and even decreased in the
super-micrometer stages; species other than nss K are more reliable tracers for biomass burning in this
region. Chloride levels were reduced in the fire sets likely due to chloride depletion by inorganic and
organic acids that exhibited elevated levels in transported plumes. During wildfire periods, the mass size
distribution of most dicarboxylic acids changed from unimodal to bimodal with peaks in the 0.32 mm and
1.0e1.8 mm stages. Furthermore, sulfate's peak concentration shifted from the 0.32 mm to 0.56 mm stage,
and nitrate also shifted to larger sizes (1.0 mm to 1.8e3.2 mm stages). Mass concentrations of numerous
soil tracer species (e.g., Si, Fe) were strongly enhanced in samples influenced by wildfires, especially in
the sub-micrometer range. Airborne cloud water data confirm that soil species were associated with fire
plumes transported south along the coast. In the absence of biomass burning, cloud condensation nuclei
(CCN) composition is dominated by nss sulfate and ammonium, and the water-soluble organic fraction is
dominated by methanesulfonate, whereas for the samples influenced by wildfires, ammonium becomes
the dominant overall species, and oxalate is the most abundant organic species.
Type
Article
Description
The article of record as published may be found at http://dx.doi.org/10.1016/j.atmosenv.2015.08.0391352-2310
Series/Report No
Department
Organization
Naval Postgraduate School (U.S.)
Identifiers
NPS Report Number
Sponsors
ONR grants N00014-11-1-0783, N00014-10-1-0200, and N00014-10-1-0811.
NOAA Air Resources Laboratory (ARL)
Naval Research Laboratory and EPA IMPROVE network
NOAA Air Resources Laboratory (ARL)
Naval Research Laboratory and EPA IMPROVE network
Funder
ONR grants N00014-11-1-0783, N00014-10-1-0200, and N00014-10-1-0811.
NOAA Air Resources Laboratory (ARL)
Naval Research Laboratory and EPA IMPROVE network
NOAA Air Resources Laboratory (ARL)
Naval Research Laboratory and EPA IMPROVE network
Format
10 p.
Citation
Atmospheric Environment 119 (2015) 59e68
Distribution Statement
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.