TY - JOUR
T1 - Effects of High Acidity on Phase Transitions of an Organic Aerosol
AU - Losey, Delanie J.
AU - Ott, Emily Jean E.
AU - Freedman, Miriam Arak
N1 - Funding Information:
Experiments and analyses were supported by the NSF CAREER program (CHE 1351383) prior to September 1, 2017 including the studies of all organic acid/ammonium sulfate/sulfuric acid systems. After this date, the project was supported by a U.S. DOE grant (DE SC0018032), including all organic acid/sulfuric acid ammonium sulfate/sulfuric acid, and organic acid/other acid studies.
Funding Information:
Experiments and analyses were supported by the NSF CAREER program (CHE 1351383) prior to September 1, 2017, including the studies of all organic acid/ammonium sulfate/sulfuric acid systems. After this date, the project was supported by a U.S. DOE grant (DE SC0018032), including all organic acid/sulfuric acid, ammonium sulfate/sulfuric acid, and organic acid/other acid studies.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/19
Y1 - 2018/4/19
N2 - Aerosol particle morphology influences the effect of particles on climate. Recent studies have documented the high acidity found in many ambient aerosol particles. The effect of this acidity on the phase transitions of mixed organic/inorganic aerosol particles has not been addressed. To investigate this effect, six organic compounds and ammonium sulfate were investigated individually with varying amounts of sulfuric acid to determine the role of low pH in the separation, efflorescence, and deliquescence transitions. All phase transitions were affected by the addition of sulfuric acid. This effect was attributed primarily to the change in the identity of the inorganic component as the ammonium/sulfate ratio (ASR) was changed from 2 to 1.5 to 1. The separation relative humidity (SRH) decreased with increasing amounts of sulfuric acid for each system studied, with the largest effect seen in compounds that have a lower SRH when mixed with ammonium sulfate. Control studies without an inorganic salt revealed that for some systems, phase separation occurs for mixtures of sulfuric acid and an organic acid. Overall, it was found that for aerosol particles at low pH (≤0.35) composed of organic acids and inorganic salts, phase separation can be impeded in some cases.
AB - Aerosol particle morphology influences the effect of particles on climate. Recent studies have documented the high acidity found in many ambient aerosol particles. The effect of this acidity on the phase transitions of mixed organic/inorganic aerosol particles has not been addressed. To investigate this effect, six organic compounds and ammonium sulfate were investigated individually with varying amounts of sulfuric acid to determine the role of low pH in the separation, efflorescence, and deliquescence transitions. All phase transitions were affected by the addition of sulfuric acid. This effect was attributed primarily to the change in the identity of the inorganic component as the ammonium/sulfate ratio (ASR) was changed from 2 to 1.5 to 1. The separation relative humidity (SRH) decreased with increasing amounts of sulfuric acid for each system studied, with the largest effect seen in compounds that have a lower SRH when mixed with ammonium sulfate. Control studies without an inorganic salt revealed that for some systems, phase separation occurs for mixtures of sulfuric acid and an organic acid. Overall, it was found that for aerosol particles at low pH (≤0.35) composed of organic acids and inorganic salts, phase separation can be impeded in some cases.
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U2 - 10.1021/acs.jpca.8b00399
DO - 10.1021/acs.jpca.8b00399
M3 - Article
C2 - 29578344
AN - SCOPUS:85045685702
SN - 1089-5639
VL - 122
SP - 3819
EP - 3828
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 15
ER -