Role of Organic Hydrocarbons in Atmospheric Ice Formation via Contact Freezing

Collier, Kristen N.

doi:10.1021/acs.jpca.6b11890

Cited by 17 publications

(33 citation statements)

References 84 publications

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“…Therefore, it is plausible that differences in molecular size explain the observed trend between SOA from different precursors. This is consistent with measurements by Collier and Brooks (), who show that oxidation of squalene, which undergoes functionalization, increased its viscosity, whereas oxidation of squalane decreased its viscosity due to molecule fragmentation. A quick survey of sensitivity to known factors controlling viscosity reveals that the ~30 °C differences in observed viscosity transition shown in Figure could be explained by the difference of a single polar functional group such as hydroxyl (OH) or carboxyl (O=COH; Rothfuss & Petters, ); structural differences in organic molecules of otherwise identical composition (Rothfuss & Petters, ); a difference in molecular weight of ~30 Da (~1 °C/Da; Shiraiwa et al, ); or a combination of these effects.…”

Section: Resultssupporting

confidence: 92%

Temperature‐ and Humidity‐Dependent Phase States of Secondary Organic Aerosols

Petters

Kreidenweis

Grieshop

et al. 2019

Geophysical Research Letters

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Viscosity of monoterpene‐derived secondary organic aerosols (SOAs) as a function of temperature and relative humidity (RH), and dry SOA glass transition temperatures are reported. Viscosity was measured using coalescence time scales of synthesized 100 nm dimers. Dry temperature‐dependent SOA viscosity was similar to that of citric acid, coal tar pitch, and sorbitol. The temperature where dry viscosity was 106 Pa·s varied between 14 and 36 °C and extrapolated glass transition varied between −10 and 20 °C (±10 °C). Mass fragment f44 obtained with an Aerosol Chemical Speciation Monitor was anticorrelated with viscosity. Viscosity of humidified Δ3‐carene and α‐pinene SOAs exceeded 106 Pa·s for all subsaturated RHs at temperatures <0 and –5 °C, respectively. Steep viscosity isopleths at 106 Pa·s were traced for these across (temperature, RH) conditions ranging from (approximately −5 °C, 100%) and (approximately 36 °C, 0%). Differences in composition and thus hygroscopicity can shift humidified viscosity isopleths for SOAs at cold tropospheric temperatures.

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Section: Resultssupporting

confidence: 92%

Temperature‐ and Humidity‐Dependent Phase States of Secondary Organic Aerosols

Petters

Kreidenweis

Grieshop

et al. 2019

Geophysical Research Letters

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“…To determine the concentration of ice‐active aerosols (those that freeze) relative to the total sample concentration, the probability of freezing, or fraction frozen, was calculated as

P ()(, T) = \frac{{bold-italicN}_{bold-italicf}}{{bold-italicN}_{bold-italico}},

where N 0 is the total number of unfrozen water droplets (including the initial unfrozen droplet and subsequent thawed droplets) and N f is the number of water droplets frozen at temperature, T (Brooks et al, ; Collier & Brooks, ; Shaw et al, ). The fraction frozen for each sample is shown in Figure .…”

Section: Resultsmentioning

confidence: 99%

“…Ice nucleation measurements were conducted using a custom ice microscope apparatus built and operated at Texas A&M University (Brooks et al, 2014;Collier & Brooks, 2016;Fornea et al, 2009). The well-established method is described in detail in our earlier work (Fornea et al, 2009) and is outlined briefly here.…”

Section: Immersion Mode Ice Nucleation Experimentsmentioning

confidence: 99%

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Ice Nucleation by Marine Aerosols Over the North Atlantic Ocean in Late Spring

et al. 2020

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Here we report the ice nucleating temperatures of marine aerosols sampled in the subarctic Atlantic Ocean during a phytoplankton bloom. Ice nucleation measurements were conducted on primary aerosol samples and phytoplankton isolated from seawater samples. Primary marine aerosol samples produced by a specialized aerosol generator (the Sea Sweep) catalyzed droplet freezing at temperatures between −33.4 °C and − 24.5 °C, with a mean freezing temperature of −28.5 °C, which was significantly warmer than the homogeneous freezing temperature of pure water in the atmosphere (−36 °C). Following a storm‐induced deep mixing event, ice nucleation activity was enhanced by two metrics: (1) the fraction of aerosols acting as ice nucleating particles (INPs) and (2) the nucleating temperatures, which were the warmest observed throughout the project. Seawater samples were collected from the ocean's surface and phytoplankton groups, including Synechococcus, picoeukaryotes, and nanoeukaryotes, were isolated into sodium chloride sheath fluid solution using a cell‐sorting flow cytometer. Marine aerosol containing Synechococcus, picoeukaryotes, and nanoeukaryotes serves as INP at temperatures significantly warmer than the homogeneous freezing temperature of pure water in the atmosphere. Samples containing whole organisms in 30 g L−1 NaCl had freezing temperatures between −33.8 and − 31.1 °C. Dilution of samples to representative atmospheric aerosol salt concentrations (as low as 3.75 g L−1 NaCl) raised freezing temperatures to as high as −22.1 °C. It follows that marine aerosols containing phytoplankton may have widespread influence on marine ice nucleation events by facilitating ice nucleation.

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“…Measurements suggest that K-feldspar, a common component of soil dust aerosol, may account for a large fraction of Earth's INPs (Atkinson et al, 2013;YakobiHancock et al, 2013). Recent investigations of other aerosols have identified aromatic pollutant aerosols, secondary organic aerosols, marine aerosols, and aerosols produced from biomass burning as effective INPs DeMott et al, 2016;McCluskey et al, 2014McCluskey et al, , 2016Levin et al, 2016;Collier and Brooks, 2016).…”

Section: Introductionmentioning

confidence: 99%

Using depolarization to quantify ice nucleating particle concentrations: a new method

Zenker

Collier

et al. 2017

Atmos. Meas. Tech.

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Abstract. We have developed a new method to determine ice nucleating particle (INP) concentrations observed by the Texas A&M University continuous flow diffusion chamber (CFDC) under a wide range of operating conditions. In this study, we evaluate differences in particle optical properties detected by the Cloud and Aerosol Spectrometer with POLarization (CASPOL) to differentiate between ice crystals, droplets, and aerosols. The depolarization signal from the CASPOL instrument is used to determine the occurrence of water droplet breakthrough (WDBT) conditions in the CFDC. The standard procedure for determining INP concentration is to count all particles that have grown beyond a nominal size cutoff as ice crystals. During WDBT this procedure overestimates INP concentration, because large droplets are miscounted as ice crystals. Here we design a new analysis method based on depolarization ratio that can extend the range of operating conditions of the CFDC. The method agrees reasonably well with the traditional method under non-WDBT conditions with a mean percent error of ±32.1 %. Additionally, a comparison with the Colorado State University CFDC shows that the new analysis method can be used reliably during WDBT conditions.

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Role of Organic Hydrocarbons in Atmospheric Ice Formation via Contact Freezing

Abstract: An optical ice microscope apparatus equipped with a sealed cooling stage and CCD camera was used to examine contact freezing events between a water droplet and ice nucleating particles (INP) containing either fresh or oxidized organic hydrocarbons.

Cited by 17 publications

References 84 publications

Temperature‐ and Humidity‐Dependent Phase States of Secondary Organic Aerosols

Temperature‐ and Humidity‐Dependent Phase States of Secondary Organic Aerosols

Ice Nucleation by Marine Aerosols Over the North Atlantic Ocean in Late Spring

Using depolarization to quantify ice nucleating particle concentrations: a new method

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