Prediction of Phase State of Secondary Organic Aerosol Internally Mixed with Aqueous Inorganic Salts

2021 ◽  
Author(s):  
Zechen Yu ◽  
Myoseon Jang ◽  
Azad Madhu
Keyword(s):  
Phase State ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Inorganic Salts

scholarly journals The effects of morphology, mobility size, and secondary organic aerosol (SOA) material coating on the ice nucleation activity of black carbon in the cirrus regime

2020 ◽  
Vol 20 (22) ◽  
pp. 13957-13984
Author(s):  
Cuiqi Zhang ◽  
Yue Zhang ◽  
Martin J. Wolf ◽  
Leonid Nichman ◽  
Chuanyang Shen ◽  
...  
Keyword(s):  
Black Carbon ◽  
State Transition ◽  
Phase State ◽  
Secondary Organic Aerosol ◽  
Global Climate ◽  
Surface Oxidation ◽  
Organic Aerosol ◽  
Ice Nucleation ◽  
Supersaturation Ratio ◽  
Homogeneous Freezing

Abstract. There is evidence that black carbon (BC) particles may affect cirrus formation and, hence, global climate by acting as potential ice nucleating particles (INPs) in the troposphere. Nevertheless, the ice nucleation (IN) ability of bare BC and BC coated with secondary organic aerosol (SOA) material remains uncertain. We have systematically examined the IN ability of 100–400 nm size-selected BC particles with different morphologies and different SOA coatings representative of anthropogenic (toluene and n-dodecane) and biogenic (β-caryophyllene) sources in the cirrus regime (−46 to −38 ∘C). Several BC proxies were selected to represent different particle morphologies and oxidation levels. Atmospheric aging was further replicated with the exposure of SOA-coated BC to OH. The results demonstrate that the 400 nm hydrophobic BC types nucleate ice only at or near the homogeneous freezing threshold. Ice formation at cirrus temperatures below homogeneous freezing thresholds, as opposed to purely homogeneous freezing, was observed to occur for some BC types between 100 and 200 nm within the investigated temperature range. More fractal BC particles did not consistently act as superior INPs over more spherical ones. SOA coating generated by oxidizing β-caryophyllene with O3 did not seem to affect BC IN ability, probably due to an SOA-phase state transition. However, SOA coatings generated from OH oxidation of various organic species did exhibit higher IN-onset supersaturation ratio with respect to ice (SSi), compared with bare BC particles, with the toluene-SOA coating showing an increase in SSi of 0.1–0.15 while still below the homogeneous freezing threshold. Slightly oxidized toluene SOA coating seemed to have a stronger deactivation effect on BC IN ability than highly oxidized toluene SOA, which might be caused by oligomer formation and the phase state transition of toluene SOA under different oxidation levels. n-dodecane and β-caryophyllene-derived SOA-coated BC only froze in the homogeneous regime. We attribute the inhibition of IN ability to the filling of the pores on the BC surface by the SOA material coating. OH exposure levels of n-dodecane and β-caryophyllene SOA coating experiments, from an equivalent atmospheric exposure time from 10 to 90 d, did not render significant differences in the IN potential. Our study of selected BC types and sizes suggests that increases in diameter, compactness, and/or surface oxidation of BC particles lead to more efficient IN via the pore condensation freezing (PCF) pathway, and that coatings of common SOA materials can inhibit the formation of ice.

Aqueous Photochemistry of Secondary Organic Aerosol of α-Pinene and α-Humulene in the Presence of Hydrogen Peroxide or Inorganic Salts

2019 ◽  
Vol 3 (12) ◽  
pp. 2736-2746 ◽  
Author(s):  
Alexandra L. Klodt ◽  
Dian E. Romonosky ◽  
Peng Lin ◽  
Julia Laskin ◽  
Alexander Laskin ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Inorganic Salts

scholarly journals Particle Size Distribution Dynamics Can Help Constrain the Phase State of Secondary Organic Aerosol

2021 ◽  
Vol 55 (3) ◽  
pp. 1466-1476
Author(s):  
Yicong He ◽  
Ali Akherati ◽  
Theodora Nah ◽  
Nga L. Ng ◽  
Lauren A. Garofalo ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Phase State ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Distribution Dynamics

scholarly journals Phase state of secondary organic aerosol in chamber photo-oxidation of mixed precursors

2021 ◽  
Vol 21 (14) ◽  
pp. 11303-11316
Author(s):  
Yu Wang ◽  
Aristeidis Voliotis ◽  
Yunqi Shao ◽  
Taomou Zong ◽  
Xiangxinyue Meng ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ammonium Sulfate ◽  
Phase State ◽  
Secondary Organic Aerosol ◽  
Inorganic Compounds ◽  
Organic Aerosol ◽  
Phase Behaviour ◽  
Hygroscopic Growth ◽  
Photo Oxidation ◽  
Aerosol Chamber

Abstract. The phase behaviour of aerosol particles plays a profound role in atmospheric physicochemical processes, influencing their physical and optical properties and further impacting climate and air quality. However, understanding of the aerosol phase state is still incomplete, especially that of multicomponent particles which contain inorganic compounds and secondary organic aerosol (SOA) from mixed volatile organic compound (VOC) precursors. We report measurements conducted in the Manchester Aerosol Chamber (MAC) to investigate the aerosol rebounding tendency, measured as the bounce fraction, as a surrogate of the aerosol phase state during SOA formation from photo-oxidation of biogenic (α-pinene and isoprene) and anthropogenic (o-cresol) VOCs and their binary mixtures on deliquescent ammonium sulfate seed. Aerosol phase state is dependent on relative humidity (RH) and chemical composition (key factors determining aerosol water uptake). Liquid (bounce fraction; BF < 0.2) at RH > 80 % and nonliquid behaviour (BF > 0.8) at RH < 30 % were observed, with a liquid-to-nonliquid transition with decreasing RH between 30 % and 80 %. This RH-dependent phase behaviour (RHBF=0.2,0.5,0.8) increased towards a maximum, with an increasing organic–inorganic mass ratio (MRorg/inorg) during SOA formation evolution in all investigated VOC systems. With the use of comparable initial ammonium sulfate seed concentration, the SOA production rate of the VOC systems determines the MRorg/inorg and, consequently, the change in the phase behaviour. Although less important than RH and MRorg/inorg, the SOA composition plays a second-order role, with differences in the liquid-to-nonliquid transition at moderate MRorg/inorg of ∼1 observed between biogenic-only (anthropogenic-free) and anthropogenic-containing VOC systems. Considering the combining role of the RH and chemical composition in aerosol phase state, the BF decreased monotonically with increasing hygroscopic growth factor (GF), and the BF was ∼0 when GF was larger than 1.15. The real atmospheric consequences of our results are that any processes changing ambient RH or MRorg/inorg (aerosol liquid water) will influence their phase state. Where abundant anthropogenic VOCs contribute to SOA, compositional changes in SOA may influence phase behaviour at moderate organic mass fraction (∼50 %) compared with purely biogenic SOA. Further studies are needed on more complex and realistic atmospheric mixtures.

scholarly journals Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

2011 ◽  
Vol 11 (3) ◽  
pp. 9313-9334
Author(s):  
A. Virtanen ◽  
J. Kannosto ◽  
J. Joutsensaari ◽  
E. Saukko ◽  
H. Kuuluvainen ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Phase State ◽  
Size Range ◽  
Secondary Organic Aerosol ◽  
Solid Phase ◽  
Particle Density ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Atmospheric Aerosol Particles ◽  
Particle Bounce

Abstract. The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA) particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol particles. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI). We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The decreasing bounce can be caused by the differences in composition and phase of large (diameters greater than 30 nm) and smaller (diameters between 17 and 30 nm) particles.

scholarly journals Phase State and Deliquescence Hysteresis of Ammonium-Sulfate-Seeded Secondary Organic Aerosol

2015 ◽  
Vol 49 (7) ◽  
pp. 531-537 ◽  
Author(s):  
Erkka Saukko ◽  
Soeren Zorn ◽  
Mikinori Kuwata ◽  
Jorma Keskinen ◽  
Annele Virtanen
Keyword(s):  
Ammonium Sulfate ◽  
Phase State ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol

scholarly journals Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

2011 ◽  
Vol 11 (16) ◽  
pp. 8759-8766 ◽  
Author(s):  
A. Virtanen ◽  
J. Kannosto ◽  
H. Kuuluvainen ◽  
A. Arffman ◽  
J. Joutsensaari ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Phase State ◽  
Size Range ◽  
Secondary Organic Aerosol ◽  
Solid Phase ◽  
Particle Density ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Limited Information ◽  
Particle Bounce

Abstract. The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA) particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI). We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The comparison measurements by ammonium sulphate and investigation of the particle impaction velocities strongly suggest that the decreasing bounce is caused by the differences in composition and phase of large (diameters greater than 30 nm) and smaller (diameters between 17 and 30 nm) particles.

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