scholarly journals Reactions between water-soluble organic acids and nitrates in atmospheric aerosols: Recycling of nitric acid and formation of organic salts

2014 ◽  
Vol 119 (6) ◽  
pp. 3335-3351 ◽  
Author(s):  
Bingbing Wang ◽  
Alexander Laskin
Keyword(s):  
Nitric Acid ◽  
Organic Acids ◽  
Atmospheric Aerosols ◽  
Water Soluble ◽  
Organic Salts

scholarly journals Hygroscopic behavior of atmospheric aerosols containing nitrates and water-soluble organic acids

2017 ◽  
Author(s):  
Bo Jing ◽  
Zhen Wang ◽  
Fang Tan ◽  
Yucong Guo ◽  
Shengrui Tong ◽  
...  
Keyword(s):  
Organic Acids ◽  
Organic Acid ◽  
Phase Behavior ◽  
Water Uptake ◽  
Sodium Nitrate ◽  
Atmospheric Aerosols ◽  
Water Soluble ◽  
Atmospheric Environment ◽  
Mass Transfer Limitation ◽  
Continuous Growth

Abstract. While nitrates have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrates remain uncertain. The hygroscopic behaviors of nitrate aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water soluble organic acids at varying mass ratios were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate/organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate particles show continuous water uptake with increasing RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-containing aerosols in the atmospheric environment.

Strong deviations from thermodynamically expected phase partitioning of organic acids during one year of rural field measurements 

2021 ◽  
Author(s):  
Andreas Tilgner ◽  
Bastian Stieger ◽  
Dominik van Pinxteren ◽  
Gerald Spindler ◽  
Laurent Poulain ◽  
...  
Keyword(s):  
Organic Acids ◽  
Gas Phase ◽  
Methanesulfonic Acid ◽  
Field Measurements ◽  
Ambient Air ◽  
Water Soluble ◽  
Particle Phase ◽  
Organic Salts ◽  
Phase Partitioning ◽  
One Year

<p>Organic acids are ubiquitous compounds in the troposphere and can affect human health, the climate, air quality, and the linked ecosystems. Depending on their solubility and volatility, they can partition in both gas phase and in the particle phase. In the particle phase, organic acids partly represent about 10% of the water-soluble organic matter. However, their partitioning between different phases is not fully understood yet. Therefore, an upgraded monitor for aerosols and gases in ambient air (MARGA) was applied for one year at the Central European TROPOS research site Melpitz to study the gas- and particle-phase partitioning of formic, acetic, propionic, butyric, glycolic, pyruvic, oxalic, malonic, succinic, malic, and methanesulfonic acid (MSA). Measured gas- and PM<sub>10</sub> particle-phase mean concentrations were 12−445 and 7−31 ng m<sup>-3</sup> for monocarboxylic acids (MCAs), between 0.6−8 and 4−31 ng m<sup>-3</sup> for dicarboxylic acids (DCAs), and 2 and 31 ng m<sup>-3</sup> for MSA, respectively. Assuming full dissolution in nonideal aerosol solutions, empirical noneffective Henry’s law constants (H<sub>emp</sub>) were calculated and compared with literature values (H<sub>lit</sub>). Calculated mean H<sub>emp</sub> were 4.5 × 10<sup>9</sup>−2.2 × 10<sup>10</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MCAs, 3.6 × 10<sup>10</sup>−7.5 × 10<sup>11</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for DCAs, and 7.5 × 10<sup>7</sup> mol L<sup>−1</sup> atm<sup>−1</sup> for MSA and, thus, factors of 5.1 × 10<sup>3</sup>−9.1 × 10<sup>5</sup> and 2.5−20.3 higher than their corresponding H<sub>lit</sub> for MCAs and DCAs, respectively, and 9.0 × 10<sup>−5</sup> lower than H<sub>lit,MSA</sub>. Data analyses and thermodynamic calculations implicate that the formation of chemical association complexes and organic salts inhibits the partitioning of organic acids toward the gas phase and, thus, at least partly explains higher H<sub>emp</sub> values for both MCAs and summertime DCAs. Low H<sub>emp,MSA</sub> are also unexpected because of the high MSA solubility and are reported for the first time in this study. Overall, the results of the present study implicate that processes responsible for the observed stronger partitioning of carboxylic acids toward the particle phase need to be further investigated and accounted for in complex multiphase chemistry models as they affect the contribution of organic acids to secondary organic aerosol mass, their chemical processing, and lifetime.</p> <p> </p> <p> </p>

scholarly journals Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

2018 ◽  
Vol 18 (7) ◽  
pp. 5115-5127 ◽  
Author(s):  
Bo Jing ◽  
Zhen Wang ◽  
Fang Tan ◽  
Yucong Guo ◽  
Shengrui Tong ◽  
...  
Keyword(s):  
Organic Acids ◽  
Phase Behavior ◽  
Water Uptake ◽  
Sodium Nitrate ◽  
Atmospheric Aerosols ◽  
Water Soluble ◽  
Atmospheric Environment ◽  
Nitrate Salt ◽  
Continuous Growth ◽  
Nitrate Salts

Abstract. While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

scholarly journals Water-soluble organic acids in sedimentary rocks: Compositions and influencing factors

2021 ◽  
Author(s):  
Pengpeng Li ◽  
Shixin Zhou ◽  
Baoqiang Ji ◽  
Xiaopeng Liu ◽  
Jing Li ◽  
...  
Keyword(s):  
Organic Acids ◽  
Influencing Factors ◽  
Sedimentary Rocks ◽  
Water Soluble

scholarly journals Characterization of Aerosol Composition, Aerosol Acidity and Organic Acid Partitioning at an Agriculture-Intensive Rural Southeastern U.S. Site

2018 ◽  
Author(s):  
Theodora Nah ◽  
Hongyu Guo ◽  
Amy P. Sullivan ◽  
Yunle Chen ◽  
David J. Tanner ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Organic Acids ◽  
Organic Acid ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Molar Concentration ◽  
Particle Phase ◽  
Aerosol Composition ◽  
Phase Water ◽  
Acetic Acids

Abstract. The implementation of stringent emission regulations has resulted in the decline of anthropogenic pollutants including sulfur dioxide (SO2), nitrogen oxides (NOx) and carbon monoxide (CO). In contrast, ammonia (NH3) emissions are largely unregulated, with emissions projected to increase in the future. We present real-time aerosol and gas measurements from a field study conducted in an agricultural-intensive region in the southeastern U.S. during the fall of 2016 to investigate how NH3 affects particle acidity and SOA formation via the gas-particle partitioning of semi-volatile organic acids. Particle water and pH were determined using the ISORROPIA-II thermodynamic model and validated by comparing predicted inorganic HNO3-NO3− and NH3-NH4+ gas-particle partitioning ratios with measured values. Our results showed that despite the high NH3 concentrations (study average 8.1 ± 5.2 ppb), PM1 were highly acidic with pH values ranging from 0.9 to 3.8, and a study-averaged pH of 2.2 ± 0.6. PM1 pH varied by approximately 1.4 units diurnally. Formic and acetic acids were the most abundant gas-phase organic acids, and oxalate was the most abundant particle-phase water-soluble organic acid anion. Measured particle-phase water-soluble organic acids were on average 6 % of the total non-refractory PM1 organic aerosol mass. The measured molar fraction of oxalic acid in the particle phase (i.e., particle-phase oxalic acid molar concentration divided by the total oxalic acid molar concentration) ranged between 47 and 90 % for PM1 pH 1.2 to 3.4. The measured oxalic acid gas-particle partitioning ratios were in good agreement with their corresponding thermodynamic predictions, calculated based on oxalic acid’s physicochemical properties, ambient temperature, particle water and pH. In contrast, gas-particle partitioning of formic and acetic acids were not well predicted for reasons currently unknown. For this study, higher NH3 concentrations relative to what has been measured in the region in previous studies had minor effects on PM1 organic acids and their influence on the overall organic aerosol and PM1 mass concentrations.

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