scholarly journals A combined particle trap/HTDMA hygroscopicity study of mixed inorganic/organic aerosol particles

2008 ◽  
Vol 8 (18) ◽  
pp. 5589-5601 ◽  
Author(s):  
A. A. Zardini ◽  
S. Sjogren ◽  
C. Marcolli ◽  
U. K. Krieger ◽  
M. Gysel ◽  
...  
Keyword(s):  
Citric Acid ◽  
Growth Factor ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Atmospheric Aerosols ◽  
Glutaric Acid ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Water Soluble

Abstract. Atmospheric aerosols are often mixtures of inorganic and organic material. Organics can represent a large fraction of the total aerosol mass and are comprised of water-soluble and insoluble compounds. Increasing attention was paid in the last decade to the capability of mixed inorganic/organic aerosol particles to take up water (hygroscopicity). We performed hygroscopicity measurements of internally mixed particles containing ammonium sulfate and carboxylic acids (citric, glutaric, adipic acid) in parallel with an electrodynamic balance (EDB) and a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds were chosen to represent three distinct physical states. During hygroscopicity cycles covering hydration and dehydration measured by the EDB and the HTDMA, pure citric acid remained always liquid, adipic acid remained always solid, while glutaric acid could be either. We show that the hygroscopicity of mixtures of the above compounds is well described by the Zdanovskii-Stokes-Robinson (ZSR) relationship as long as the two-component particle is completely liquid in the ammonium sulfate/glutaric acid system; deviations up to 10% in mass growth factor (corresponding to deviations up to 3.5% in size growth factor) are observed for the ammonium sulfate/citric acid 1:1 mixture at 80% RH. We observe even more significant discrepancies compared to what is expected from bulk thermodynamics when a solid component is present. We explain this in terms of a complex morphology resulting from the crystallization process leading to veins, pores, and grain boundaries which allow for water sorption in excess of bulk thermodynamic predictions caused by the inverse Kelvin effect on concave surfaces.

scholarly journals A combined particle trap/HTDMA hygroscopicity study of mixed inorganic/organic aerosol particles

2008 ◽  
Vol 8 (2) ◽  
pp. 5235-5268 ◽  
Author(s):  
A. A. Zardini ◽  
S. Sjogren ◽  
C. Marcolli ◽  
U. K. Krieger ◽  
M. Gysel ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Atmospheric Aerosols ◽  
Glutaric Acid ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Component Particle

Abstract. Atmospheric aerosols are often mixtures of inorganic and organic material. Organics can represent a large fraction of the total aerosol mass and are comprised of water-soluble and insoluble compounds. Increasing attention was paid in the last decade to the capability of mixed inorganic/organic aerosol particles to take up water (hygroscopicity). We performed hygroscopicity measurements of internally mixed particles containing ammonium sulfate and carboxylic acids (citric, glutaric, adipic acid) in parallel with an electrodynamic balance (EDB) and a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds were chosen to represent three distinct physical states. During hygroscopicity cycles covering hydration and dehydration measured by the EDB and the HTDMA, pure citric acid remained always liquid, adipic acid remained always solid, while glutaric acid could be either. We show that the hygroscopicity of mixtures of the above compounds is well described by the Zdanovskii-Stokes-Robinson (ZSR) relationship as long as the two-component particle is completely liquid in the ammonium sulfate/citric acid and in the ammonium sulfate/glutaric acid cases. However, we observe significant discrepancies compared to what is expected from bulk thermodynamics when a solid component is present. We explain this in terms of a complex morphology resulting from the crystallization process leading to veins, pores, and grain boundaries which allow for water sorption in excess of bulk thermodynamic predictions caused by the inverse Kelvin effect on concave surfaces.

scholarly journals A novel tandem differential mobility analyzer with organic vapor treatment of aerosol particles

2001 ◽  
Vol 1 (1) ◽  
pp. 51-60 ◽  
Author(s):  
J. Joutsensaari ◽  
P. Vaattovaara ◽  
M. Vesterinen ◽  
K. Hämeri ◽  
A. Laaksonen
Keyword(s):  
Water Vapor ◽  
Sodium Chloride ◽  
Citric Acid ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Aerosol Particles ◽  
Ethanol Vapor ◽  
Differential Mobility Analyzer ◽  
Differential Mobility ◽  
Organic Vapor

Abstract. A novel method to characterize the organic composition of aerosol particles has been developed. The method is based on organic vapor interaction with aerosol particles and it has been named an Organic Tandem Differential Mobility Analyzer (OTDMA). The OTDMA method has been tested for inorganic (sodium chloride and ammonium sulfate) and organic (citric acid and adipic acid) particles. Growth curves of the particles have been measured in ethanol vapor and as a comparison in water vapor as a function of saturation ratio. Measurements in water vapor show that sodium chloride and ammonium sulfate as well as citric acid particles grow at water saturation ratios (S) of 0.8 and above, whereas adipic acid particles do not grow at S <  0.96. For sodium chloride and ammonium sulfate particles, a deliquescence point is observed at S = 0.75 and S = 0.79, respectively. Citric acid particles grow monotonously with increasing saturation ratios already at low saturation ratios and no clear deliquescence point is found. For sodium chloride and ammonium sulfate particles, no growth can be seen in ethanol vapor at saturation ratios below 0.93. In contrast, for adipic acid particles, the deliquescence takes place at around S = 0.95 in the ethanol vapor. The recrystallization of adipic acid takes place at S < 0.4. Citric acid particles grow in ethanol vapor similarly as in water vapor; the particles grow monotonously with increasing saturation ratios and no stepwise deliquescence is observed. The results show that the working principles of the OTDMA are operational for single-component aerosols. Furthermore, the results indicate that the OTDMA method may prove useful in determining whether aerosol particles contain organic substances, especially if the OTDMA is operated in parallel with a hygroscopicity TDMA, as the growth of many substances is different in ethanol and water vapors.

scholarly journals A novel tandem differential mobility analyzer with organic vapor treatment of aerosol particles

2001 ◽  
Vol 1 (1) ◽  
pp. 1-22 ◽  
Author(s):  
J. Joutsensaari ◽  
P. Vaattovaara ◽  
K. Hämeri ◽  
A. Laaksonen
Keyword(s):  
Water Vapor ◽  
Sodium Chloride ◽  
Citric Acid ◽  
Ammonium Sulfate ◽  
Adipic Acid ◽  
Aerosol Particles ◽  
Ethanol Vapor ◽  
Differential Mobility ◽  
Organic Vapor ◽  
Organic Composition

Abstract. A novel method to characterize the organic composition of aerosol particles has been developed. The method is based on organic vapor interaction with aerosol particles and it has been named an Organic Tandem Differential Mobility Analyzer (OTDMA). The OTDMA method has been tested for inorganic (sodium chloride and ammonium sulfate) and organic (citric acid and adipic acid) particles. Growth curves of the particles have been measured in ethanol vapor and as a comparison in water vapor as a function of saturation ratio. Measurements in water vapor show that sodium chloride and ammonium sulfate as well as citric acid particles grow at water saturation ratios (S) of 0.8 and above, whereas adipic acid particles do not grow at S<0.96. For sodium chloride and ammonium sulfate particles, a deliquescence point is observed at S=0.75 and S=0.79, respectively. Citric acid particles grow monotonously with increasing saturation ratios already at low saturation ratios and no clear deliquescence point is found. For inorganic sodium chloride and ammonium sulfate particles, no growth can be seen in ethanol vapor at saturation ratios below 0.9. In contrast, for organic adipic acid particles, the deliquescence takes place at around S=0.95 in the ethanol vapor. Citric acid particles grow in ethanol vapor similarly as in water vapor; the particles grow monotonously with increasing saturation ratios and no stepwise deliquescence is observed. The results show that the working principles of the OTDMA are operational and the OTDMA method can be used to determine an organic composition of the aerosol particles. Operation of OTDMA and hygroscopicity TDMA together allows making a rough categorization of different substances found in atmospheric aerosol particles based on their growth in pure ethanol and pure water vapor.

scholarly journals Comparison of secondary organic aerosol formation from toluene on initially wet and dry ammonium sulfate particles

2017 ◽  
Author(s):  
Tengyu Liu ◽  
Dan Dan Huang ◽  
Zijun Li ◽  
Qianyun Liu ◽  
ManNin Chan ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Functional Groups ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Seed Particles ◽  
The Difference ◽  
Wet Particles

Abstract. The formation of secondary organic aerosol (SOA) has been widely studied in the presence of dry seed particles at low relative humidity (RH). At higher RH, seed particles can exist as dry or wet particles. Here, we investigated the formation of SOA from the photooxidation of toluene using an oxidation flow reactor under a range of OH exposures on initially wet or dry ammonium sulfate (AS) seed particles at an RH of 68 %. At an OH exposure of 4.66 × 1010 molecules cm -3 s, the ratio of the SOA yield on wet AS seeds to that on dry AS seeds was 1.31 ± 0.02. However, this ratio decreased to 1.01 ± 0.01 at an OH exposure of 5.28 × 1011 molecules cm -3 s. The decrease in the ratios of SOA yields as the increase of OH exposure may be due to the early deliquescence of initially dry AS seeds after coated by highly oxidized toluene-derived SOA. SOA formation lowered the deliquescence RH of AS and resulted in the uptake of water by both AS and SOA. Hence the initially dry AS seeds contained aerosol liquid water (ALW) soon after a large fraction of SOA formed and the SOA yield and ALW approached those of the initially wet AS seeds as OH exposure and ALW increased. However, a higher oxidation state of the SOA on initially wet AS seeds than that on dry AS seeds was observed at all levels of OH exposure. The difference in mass fractions of m/z 29, 43 and 44 of SOA mass spectra indicated that SOA formed on initially wet seeds may be enriched in earlier-generation products containing carbonyl functional groups at low OH exposures and later-generation products containing acidic functional groups at high exposures. Our results suggest that AS dry seeds soon turn to at least partially deliquesced particles during SOA formation and more studies on the interplay of SOA formation and ALW are warranted.

scholarly journals Characterization of high molecular weight compounds in urban atmospheric particles

2005 ◽  
Vol 5 (8) ◽  
pp. 2163-2170 ◽  
Author(s):  
V. Samburova ◽  
R. Zenobi ◽  
M. Kalberer
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Atmospheric Aerosols ◽  
Uv Spectroscopy ◽  
Organic Aerosol ◽  
Large Mass ◽  
Water Soluble ◽  
Size Exclusion ◽  
Ionization Mass ◽  
Exclusion Chromatography

Abstract. The chemical nature of a large mass fraction of ambient organic aerosol particles is not known. High molecular weight compounds (often named humic-like substances) have recently been detected by several authors and these compounds seem to account for a significant fraction of the total organic aerosol mass. Due to the unknown chemical structure of these compounds quantification as well as a determination of their molecular weight is difficult. In this paper we investigate water soluble humic-like substances in ambient urban aerosol using size exclusion chromatography-UV spectroscopy and laser desorption/ionization mass spectrometry (LDI-MS). LDI-MS was used for the first time to investigate HULIS from atmospheric aerosols. A careful evaluation of the two method shows that both methods complement each other and that both are needed to learn more about the molecular weight distribution and the concentration of humic-like substances. An upper molecular weight limit of humic-like substances of about 700 Da and a concentration of 0.3-1.6 µg/m3 air can be estimated, corresponding to 9-30% of the total organic carbon for an urban background site.

scholarly journals Spatial and seasonal variations of fine particle water-soluble organic carbon (WSOC) over the southeastern United States: implications for secondary organic aerosol formation

2012 ◽  
Vol 12 (14) ◽  
pp. 6593-6607 ◽  
Author(s):  
X. Zhang ◽  
Z. Liu ◽  
A. Hecobian ◽  
M. Zheng ◽  
N. H. Frank ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Ammonium Sulfate ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Southeastern Us ◽  
Urban Rural ◽  
Water Soluble Organic Carbon ◽  
Soluble Organic Carbon

Abstract. Secondary organic aerosol (SOA) in the southeastern US is investigated by analyzing the spatial-temporal distribution of water-soluble organic carbon (WSOC) and other PM2.5 components from 900 archived 24-h Teflon filters collected at 15 urban or rural EPA Federal Reference Method (FRM) network sites throughout 2007. Online measurements of WSOC at an urban/rural-paired site in Georgia in the summer of 2008 are contrasted to the filter data. Based on FRM filters, excluding biomass-burning events (levoglucosan < 50 ng m−3), WSOC and sulfate were highly correlated with PM2.5 mass (r2~0.7). Both components comprised a large mass fraction of PM2.5 (13% and 31%, respectively, or ~25% and 50% for WSOM and ammonium sulfate). Sulfate and WSOC both tracked ambient temperature throughout the year, suggesting the temperature effects were mainly linked to faster photochemistry and/or synoptic meteorology and less due to enhanced biogenic hydrocarbon emissions. FRM WSOC, and to a lesser extent sulfate, were spatially homogeneous throughout the region, yet WSOC was moderately enhanced (27%) in locations of greater predicted isoprene emissions in summer. A Positive Matrix Factorization (PMF) analysis identified two major source types for the summer WSOC; 22% of the WSOC were associated with ammonium sulfate, and 56% of the WSOC were associated with brown carbon and oxalate. A small urban excess of FRM WSOC (10%) was observed in the summer of 2007, however, comparisons of online WSOC measurements at one urban/rural pair (Atlanta/Yorkville) in August 2008 showed substantially greater difference in WSOC (31%) relative to the FRM data, suggesting a low bias for urban filters. The measured Atlanta urban excess, combined with the estimated boundary layer heights, gave an estimated Atlanta daily WSOC production rate in August of 0.55 mgC m−2 h−1 between mid-morning and mid-afternoon. This study characterizes the regional nature of fine particles in the southeastern US, confirming the importance of SOA and the roles of both biogenic and anthropogenic emissions.

scholarly journals Characterization of high molecular weight compounds in urban atmospheric particles

2005 ◽  
Vol 5 (1) ◽  
pp. 437-454 ◽  
Author(s):  
V. Samburova ◽  
M. Kalberer ◽  
R. Zenobi
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Uv Spectroscopy ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Size Exclusion ◽  
Ionization Mass ◽  
Aerosol Mass ◽  
Exclusion Chromatography

Abstract. The chemical nature of a large fraction of ambient organic aerosol particles is not known. However, high molecular weight compounds (often named humic-like substances) have recently been detected by several authors and these compounds seem to account for a significant fraction of the total organic aerosol mass. Due to the unknown chemical structure of these compounds a quantification as well as a determination of their molecular weight is difficult. In this paper we investigate water soluble humic-like substances in ambient urban aerosol using size exclusion chromatography-UV spectroscopy and laser desorption/ionization mass spectrometry. A careful method evaluation shows that both methods complement each other and that both are needed to learn more about the molecular weight distribution and the concentration of humic-like substances. An upper molecular weight limit of humic-like substances of about 700 Da and a concentration of 0.2–1.8 µg/m3 air can be estimated corresponding to 8–33% of the total organic carbon for an urban background site.

Omnipresence of biological material in the atmosphere

2007 ◽  
Vol 4 (4) ◽  
pp. 217 ◽  
Author(s):  
Ruprecht Jaenicke ◽  
Sabine Matthias-Maser ◽  
Sabine Gruber
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Biological Material ◽  
Total Mass ◽  
Large Fraction ◽  
Aerosol Particles ◽  
Climate Forcing ◽  
The Past ◽  
Biological Particles ◽  
Precipitation Formation

Environmental context. Atmospheric biological particles have been largely overlooked in the past. While some microorganisms have been studied, the majority of other biological particles have not. The presence of these particles might force us to view the atmospheric aerosol differently. Abstract. Measurements of biological particles in the atmosphere during the last decade indicate that the presence of these particles seems to have been underestimated by atmospheric scientists. On the average these primary aerosol particles might be present as much as 25% of the total mass (or number for particles with radius greater than 0.2 µm) concentration of the atmospheric aerosol. Such a large fraction certainly plays a major role in all processes affected by atmospheric aerosols, such as cloud and precipitation formation, climate forcing, visibility, turbidity, and so on. This disregard of the biological particles requires a new attitude in our opinion.

scholarly journals Hygroscopic and phase separation properties of ammonium sulfate/organics/water ternary solutions

2015 ◽  
Vol 15 (15) ◽  
pp. 8975-8986 ◽  
Author(s):  
M. A. Zawadowicz ◽  
S. R. Proud ◽  
S. S. Seppalainen ◽  
D. J. Cziczo
Keyword(s):  
Phase Separation ◽  
Ammonium Sulfate ◽  
Atmospheric Aerosols ◽  
Aerosol Particles ◽  
Field Measurements ◽  
Inorganic Salts ◽  
Ample Evidence ◽  
Hygroscopic Properties ◽  
Inorganic Aerosol

Abstract. Atmospheric aerosol particles are often partially or completely composed of inorganic salts, such as ammonium sulfate and sodium chloride, and therefore exhibit hygroscopic properties. Many inorganic salts have well-defined deliquescence and efflorescence points at which they take up and lose water, respectively. Field measurements have shown that atmospheric aerosols are not typically pure inorganic salt, instead, they often also contain organic species. There is ample evidence from laboratory studies that suggests that mixed particles exist in a phase-separated state, with an aqueous inorganic core and organic shell. Although phase separation has not been measured in situ, there is no reason it would not also take place in the atmosphere. Here, we investigate the deliquescence and efflorescence points, phase separation and ability to exchange gas-phase components of mixed organic and inorganic aerosol using a flow tube coupled with FTIR (Fourier transform infrared) spectroscopy. Ammonium sulfate aerosol mixed with organic polyols with different O : C ratios, including 1,4-butanediol, glycerol, 1,2,6-hexanetriol, 1,2-hexanediol, and 1,5-pentanediol have been investigated. Those constituents correspond to materials found in the atmosphere in great abundance and, therefore, particles prepared in this study should mimic atmospheric mixed-phase aerosol particles. Some results of this study tend to be in agreement with previous microscopy experiments, but others, such as phase separation properties of 1,2,6-hexanetriol, do not agree with previous work. Because the particles studied in this experiment are of a smaller size than those used in microscopy studies, the discrepancies found could be a size-related effect.

Sign in / Sign up

Export Citation Format

Share Document