scholarly journals Particle partitioning potential of organic compounds is highest in the Eastern US and driven by anthropogenic water

2013 ◽  
Vol 13 (5) ◽  
pp. 12743-12770 ◽  
Author(s):  
A. G. Carlton ◽  
B. J. Turpin

Abstract. Gas phase water-soluble organic matter (WSOMg) is ubiquitous in the troposphere. In the summertime, the potential for these gases to partition to particle phase liquid water (H2Optcl) where they can form secondary organic aerosol (SOAAQ) is high in the Eastern US and low elsewhere, with the exception of an area near Los Angeles, CA. This spatial pattern is driven by mass concentrations of H2Optcl, not WSOMg. H2Optcl mass concentrations are predicted to be high in the Eastern US, largely due to sulfate. The ability of sulfate to increase H2Optcl is well-established and routinely included in atmospheric models, however WSOMg partitioning to this water and subsequent SOA formation is not. The high mass concentrations of H2Optcl in the southeast (SE) US but not the Amazon, may help explain why biogenic SOA mass concentrations are high in the SE US, but low in the Amazon. Furthermore, during the summertime in the Eastern US, the potential for organic gases to partition into liquid water is greater than their potential to partition into organic matter (OM) because concentrations of WSOMg and H2Optcl are higher than semi-volatile gases and OM. Thus, unless condensed phase yields are substantially different (> ~ order of magnitude), we expect that SOA formed through aqueous phase pathways (SOAAQ) will dominate in the Eastern US. These findings also suggest that H2Optcl is largely anthropogenic and provide a previously unrecognized mechanism by which anthropogenic pollutants impact the amount of SOA mass formed from biogenic organic emissions. The previously reported estimate of the controllable fraction of biogenic SOA in the Eastern US (50%) is likely too low.

2013 ◽  
Vol 13 (20) ◽  
pp. 10203-10214 ◽  
Author(s):  
A. G. Carlton ◽  
B. J. Turpin

Abstract. Gas-phase water-soluble organic matter (WSOMg) is ubiquitous in the troposphere. In the summertime, the potential for these gases to partition to particle-phase liquid water (H2Optcl) where they can form secondary organic aerosol (SOAAQ) is high in the Eastern US and low elsewhere, with the exception of an area near Los Angeles, CA. This spatial pattern is driven by mass concentrations of H2Optcl, not WSOMg. H2Optcl mass concentrations are predicted to be high in the Eastern US, largely due to sulfate. The ability of sulfate to increase H2Optcl is well established and routinely included in atmospheric models; however WSOMg partitioning to this water and subsequent SOA formation is not. The high mass concentrations of H2Optcl in the southeast (SE) US but not the Amazon may help explain why biogenic SOA mass concentrations are high in the SE US but low in the Amazon. Furthermore, during the summertime in the Eastern US, the potential for organic gases to partition into liquid water is greater than their potential to partition into organic matter (OM) because concentrations of WSOMg and H2Optcl are higher than semi-volatile gases and OM. Thus, unless condensed phase yields are substantially different (> ~ order of magnitude), we expect that SOA formed through aqueous-phase pathways (SOAAQ) will dominate in the Eastern US. These findings also suggest that H2Optcl is largely anthropogenic and provide a previously unrecognized mechanism by which anthropogenic pollutants impact the amount of SOA mass formed from biogenic organic emissions. The previously reported estimate of the controllable fraction of biogenic SOA in the Eastern US (50%) is likely too low.


2020 ◽  
Author(s):  
Jonathan V. Trueblood ◽  
Alesia Nicosia ◽  
Anja Engel ◽  
Birthe Zäncker ◽  
Matteo Rinaldi ◽  
...  

Abstract. Ice nucleating particles (INP) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSA), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INP, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INP are derived from two separate classes of organic matter in SSA. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as total organic carbon (TOC) or SSA surface area, which may mask specific trends in the separate classes of INPs. The goal of this paper is to improve the understanding of the connection between ocean biology and marine INP abundance by reporting results from a field study and proposing a new parameterization of marine INP that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from May 10 to June 10, 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer (SML) and in SSA produced using a plunging aquarium apparatus were continuously monitored while surface seawater (SSW) and SML biological properties were measured in parallel. The organic content of artificially generated SSA was also evaluated. A dust wet deposition event that occurred during the cruise increased the INP concentrations measured in the SML by an order of magnitude, in line with increases of iron in the SML and bacterial abundances. Increases of INPs in marine SSA (INPSSA) were not observed before a delay of three days compared to increases in the SML, and are likely a result of a strong influence of bulk SSW INP for the temperatures investigated (T = −18 °C for SSA, T = −16 °C for SSW). Results confirmed that INPSSA are divided into two classes depending on their associated organic matter. Here we find that warm (T ≥ −22 °C) INPSSA concentrations are correlated with water soluble organic matter in the SSA, but also to SSW parameters (POCSSW INPSSW,−16 °C) while cold INPSSA (T 


2014 ◽  
Vol 14 (20) ◽  
pp. 10911-10930 ◽  
Author(s):  
T. K. V. Nguyen ◽  
M. D. Petters ◽  
S. R. Suda ◽  
H. Guo ◽  
R. J. Weber ◽  
...  

Abstract. We present in situ measurements of particle-phase liquid water. Measurements were conducted from 3 June to 15 July 2013 during the Southern Oxidant and Aerosol Study (SOAS) in the southeastern US. The region is photochemically active, humid, dominated by biogenic emissions, impacted by anthropogenic pollution, and known to contain high concentrations of organic aerosol mass. Measurements characterized mobility number size distributions of ambient atmospheric aerosols in three states: unperturbed, dry, and dry-humidified. Unperturbed measurements describe the aerosol distribution at ambient temperature and relative humidity. For the dry state, the sample was routed through a cold trap upstream of the inlet then reheated, while for the dry-humidified state the sample was rehumidified after drying. The total volume of water and semi-volatile compounds lost during drying was quantified by differencing dry and unperturbed volumes from the integrated size spectra, while semi-volatile volumes lost during drying were quantified differencing unperturbed and dry-humidified volumes. Results indicate that particle-phase liquid water was always present. Throughout the SOAS campaign, median water mass concentrations at the relative humidity (RH) encountered in the instrument typically ranged from 1 to 5 μg m−3 but were as high as 73 μg m−3. On non-raining days, morning time (06:00–09:00) median mass concentrations exceeded 15 μg m−3. Hygroscopic growth factors followed a diel cycle and exceed 2 from 07:00 to 09:00 local time. The hygroscopicity parameter kappa ranged from 0.14 to 0.46 and hygroscopicity increased with increasing particle size. An observed diel cycle in kappa is consistent with changes in aerosol inorganic content and a dependency of the hygroscopicity parameter on water content. Unperturbed and dry-humidified aerosol volumes did not result in statistically discernible differences, demonstrating that drying did not lead to large losses in dry particle volume. We anticipate that our results will help improve the representation of aerosol water content and aqueous-phase-mediated partitioning of atmospheric water-soluble gases in photochemical models.


2007 ◽  
Vol 6 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Stephen A. Bowden ◽  
Rab Wilson ◽  
Colin Taylor ◽  
Jonathan M. Cooper ◽  
John Parnell

Water-soluble sulphate minerals such as epsomite and gypsum have been reported on a number of planetary bodies of astrobiological interest and their presence is often used as an indicator for potential habitability as it can indicate the presence of liquid water. The sulphate minerals can incorporate biomarkers and biomolecules as intracrystalline inclusions. These intracrystalline inclusions are protected from their exterior chemical environments and their analysis can yield a biomarker record, even in environments where extreme oxidizing conditions may have degraded any record present in non-intracrystalline organic matter. In this study, organic compounds were incorporated within epsomite as intracrystalline inclusions by co-precipitating a mineral from solutions of a mineral and organic compound. A feasibly study utilizing a microfluidic H-cell to process finely ground samples of the inclusion-bearing epsomite indicates that a similar device may be used to extract biomarkers for analysis.


2021 ◽  
Vol 503 (2) ◽  
pp. 3081-3088
Author(s):  
V K Dubrovich ◽  
Yu N Eroshenko ◽  
S I Grachev

ABSTRACT We consider a primordial black hole of very high mass, $10^9\!-\!10^{10}\, \mathrm{M}_\odot$, surrounded by the dark matter and bayonic halo at redshifts z ∼ 20 without any local sources of energy release. Such heavy and concentrated objects in the early Universe were previously called ‘cosmological dinosaurs’. Spectral distribution and spatial variation of the brightness in the 21-cm line of atomic hydrogen are calculated with the theory of radiation transfer. It is shown that a narrow and deep absorption arises in the form of the spherical shell around the primordial black hole at the certain radius. The parameters of this shell depend almost exclusively on the mass of the black hole. The angular diameter 18 arcsec of the absorption ring at z ∼ 20 is well within the current technical possibilities of the Square Kilometre Array type telescopes. But the observation of the ring width itself requires an order of magnitude better resolution.


2018 ◽  
Author(s):  
Theodora Nah ◽  
Hongyu Guo ◽  
Amy P. Sullivan ◽  
Yunle Chen ◽  
David J. Tanner ◽  
...  

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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