Water absorption by secondary organic aerosol and its effect an inorganic aerosol behavior. Ansari, A., S. & Pandis, S., N. Environ. Sci. Technol., 34:71-77, 2000.
abstract   bibtex   
The hygroscopic nature of atmospheric aerosol has generally been associated with its inorganic fraction. In this study, a group contribution method is used to predict the water absorption of secondary organic aerosol (SOA). Compared against growth measurements of mixed inorganic-organic particles, this method appears to provide a first-order approximation in predicting SOA water absorption. The growth of common SOA species is predicted to be significantly less than common atmospheric inorganic salts such as (NH4)(2)SO4 and NaCl. Using this group contribution method as a tool in predicting SOA water absorption, an integrated modeling approach is developed combining available SOA and inorganic aerosol models to predict overall aerosol behavior. The effect of SOA on water absorption and nitrate partitioning between the gas and aerosol phases is determined. On average, it appears that SOA accounts for approximately 7% of total aerosol water and increases aerosol nitrate concentrations by approximately 10%. At high relative humidity (greater than or equal to 85%) and low SOA mass fractions (<20% of total PM2.5), the role of SOA in nitrate partitioning and its contribution to total aerosol water is negligible. However, the water absorption of SOA appears to be less sensitive to changes in relative humidity than that of inorganic species, and thus at low relative humidity (similar to 50%) and high SOA mass fraction concentrations (similar to 30% of total PM2.5), SOA is predicted to account for approximately 20% of total aerosol water and a 50% increase in aerosol nitrate concentrations. These findings could improve the results of modeling studies where aerosol nitrate has often been underpredicted. C1 Carnegie Mellon Univ, Dept Chem Engn, Pittsburgh, PA 15213 USA. Carnegie Mellon Univ, Dept Engn & Publ Policy, Pittsburgh, PA 15213 USA.
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 title = {Water absorption by secondary organic aerosol and its effect an inorganic aerosol behavior},
 type = {article},
 year = {2000},
 identifiers = {[object Object]},
 pages = {71-77},
 volume = {34},
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 created = {2014-10-08T16:28:18.000Z},
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 last_modified = {2017-03-14T17:32:24.802Z},
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 citation_key = {Ansari:EST:2000a},
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 abstract = {The hygroscopic nature of atmospheric aerosol has
generally been associated with its inorganic fraction. In this
study, a group contribution method is used to predict the water
absorption of secondary organic aerosol (SOA). Compared against
growth measurements of mixed inorganic-organic particles, this
method appears to provide a first-order approximation in predicting
SOA water absorption. The growth of common SOA species is predicted
to be significantly less than common atmospheric inorganic salts
such as (NH4)(2)SO4 and NaCl. Using this group contribution method
as a tool in predicting SOA water absorption, an integrated
modeling approach is developed combining available SOA and
inorganic aerosol models to predict overall aerosol behavior. The
effect of SOA on water absorption and nitrate partitioning between
the gas and aerosol phases is determined. On average, it appears
that SOA accounts for approximately 7% of total aerosol water and
increases aerosol nitrate concentrations by approximately 10%. At
high relative humidity (greater than or equal to 85%) and low SOA
mass fractions (&lt;20% of total PM2.5), the role of SOA in nitrate
partitioning and its contribution to total aerosol water is
negligible. However, the water absorption of SOA appears to be less
sensitive to changes in relative humidity than that of inorganic
species, and thus at low relative humidity (similar to 50%) and
high SOA mass fraction concentrations (similar to 30% of total
PM2.5), SOA is predicted to account for approximately 20% of total
aerosol water and a 50% increase in aerosol nitrate
concentrations. These findings could improve the results of
modeling studies where aerosol nitrate has often been
underpredicted.
C1 Carnegie Mellon Univ, Dept Chem Engn, Pittsburgh, PA 15213 USA.
Carnegie Mellon Univ, Dept Engn &amp; Publ Policy, Pittsburgh, PA
15213 USA.},
 bibtype = {article},
 author = {Ansari, A S and Pandis, S N},
 journal = {Environ. Sci. Technol.}
}

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