Hygroscopicity, CCN and volatility properties of submicron atmospheric aerosol in a boreal forest environment during the summer of 2010

Abstract. The Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) was applied to study the hygroscopicity and volatility properties of submicron atmospheric aerosol in a boreal forest environment in Hyytiälä, Finland during the summer of 2010. Aitken and accumulation mode particles (50 nm, 75 nm and 110 nm) were investigated. The results suggest that the particles were internally mixed at all sizes. Hygroscopicity was found to increase with size. The relative mass fraction of organics and SO42− is probably the major contributor to the fluctuation of the hygroscopicity for all particle sizes. The Cloud Condensation Nuclei counter (CCNc)-derived hygroscopicity parameter κ was slightly higher than κ calculated from VH-TDMA data under sub-saturated conditions, which can be explained by the fact that particulate organics have a different degree of dissolution in sub- and supersaturated conditions. Also, the size-resolved volatility properties of particles were investigated. Upon heating, small particles evaporated more compared to large particles. There was a significant amount of aerosol volume (non-volatile material) left even at heating temperatures above 280 °C. Using size resolved volatility-hygroscopicity analysis, we concluded that there was always hygroscopic material remaining in the particles of different sizes at all different heating temperatures, even above 280 °C. This indicates that the observed non-volatile aerosol material was not consisting solely of black carbon.

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Hygroscopicity, CCN and volatility properties of submicron atmospheric aerosol in a boreal forest environment during the summer of 2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-4733-2014 ◽

2014 ◽

Vol 14 (9) ◽

pp. 4733-4748 ◽

Cited By ~ 37

Author(s):

J. Hong ◽

S. A. K. Häkkinen ◽

M. Paramonov ◽

M. Äijälä ◽

J. Hakala ◽

...

Keyword(s):

Boreal Forest ◽

Atmospheric Aerosol ◽

Cloud Condensation Nuclei ◽

Relative Mass ◽

Particle Sizes ◽

Volatile Material ◽

Differential Mobility ◽

Forest Environment ◽

Large Particles ◽

Aerosol Volume

Abstract. A Volatility-Hygroscopicity Tandem Differential Mobility Analyzer (VH-TDMA) was applied to study the hygroscopicity and volatility properties of submicron atmospheric aerosol particles in a boreal forest environment in Hyytiälä, Finland during the summer of 2010. Aitken and accumulation mode internally mixed particles (50 nm, 75 nm and 110 nm in diameter) were investigated. Hygroscopicity was found to increase with particle size. The relative mass fraction of organics and SO42- is probably the major contributor to the fluctuation of the hygroscopicity for all particle sizes. The Cloud Condensation Nuclei Counter (CCNC)-derived hygroscopicity parameter κ was observed to be slightly higher than κ calculated from VH-TDMA data under sub-saturated conditions, potential reasons for this behavior are discussed shortly. Also, the size-resolved volatility properties of particles were investigated. Upon heating, more small particles evaporated compared to large particles. There was a significant amount of aerosol volume (non-volatile material) left, even at heating temperatures of 280 °C. Using size resolved volatility-hygroscopicity analysis, we concluded that there was always hygroscopic material remaining in the particles at different heating temperatures, even at 280 °C. This indicates that the observed non-volatile aerosol material did not consist solely of black carbon.

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Transformation of marine air masses in the Fennoscandian Boreal forest – changes in aerosol, humidity, and clouds

10.5194/ems2021-175 ◽

2021 ◽

Author(s):

Meri Räty ◽

Larisa Sogacheva ◽

Helmi-Marja Keskinen ◽

Veli-Matti Kerminen ◽

Tuukka Petäjä ◽

...

Keyword(s):

Boreal Forest ◽

Water Vapour ◽

Cloud Condensation Nuclei ◽

Source Region ◽

Cloud Formation ◽

Condensation Nuclei ◽

Forest Environment ◽

Transport Time ◽

Air Mass ◽

Air Masses

Fennoscandian boreal forest is a region with commonly occurring particle formation, which benefits from the abundance of biogenic volatile organic compounds emitted by the vegetation. The same vegetation also regulates the exchange of water vapour between the ecosystem and the atmosphere. Thus, as the forest has the potential to provide the two components needed in cloud formation, i.e. condensation nuclei and humidity, there is reason to suspect consequent changes in air masses that are influenced by the forest below.We investigated the link between boreal forest air mass transport and cloud related properties in air masses that arrived to the SMEAR II station (61&#176;10&#8217;N, 24&#176;17&#8217;E, 170m a.s.l.), Finland, from between western and norther directions. These selected air masses were originally marine and travelled only across a land area with relatively minor anthropogenic emissions sources, allowing us to focus on biogenic influences. The source region and the time each air mass spent above land before arrival, were determined from 96-hour long air mass back trajectories. We used a long-term comprehensive data sets, spanning up to 11 growing seasons (April-September, 2006-2016).Air masses with short transport times over the forest, often coincided with measurements of particles in smaller size ranges. Higher numbers of larger cloud condensation nuclei sized particles became more common in air masses with longer transport times over the forest. Similarly, air masses that spent little time over land, were often relatively cool and carried less water vapour. Whereas, higher specific humidities were more likely in air masses with longer times spent over land, as associated warming had most likely facilitated an increased uptake of water vapour from plant evapotranspiration. We also observed corresponding moderate increases in satellite observed cloud optical thickness and in-situ measured precipitation. Air masses with very short transport times over land were an exception, as these fast-moving air masses are likely to be connected to weather fronts and therefore also have a high probability for clouds and precipitation. The reported differences between air masses more or less disappeared when the transport time over land reached approximately 60 hours, and any further increase in land transport time no longer caused a substantial change. This appears to be the time scale in which most of the forest environment&#8217;s influence on these cloud related properties is realised and a balance is reached.

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Aerosol particle formation in the upper residual layer

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-7901-2021 ◽

2021 ◽

Vol 21 (10) ◽

pp. 7901-7915

Author(s):

Janne Lampilahti ◽

Katri Leino ◽

Antti Manninen ◽

Pyry Poutanen ◽

Anna Franck ◽

...

Keyword(s):

Boundary Layer ◽

Boreal Forest ◽

Mixed Layer ◽

Cloud Condensation Nuclei ◽

Large Fraction ◽

Aerosol Particles ◽

Lower Troposphere ◽

Particle Formation ◽

Residual Layer ◽

Forest Environment

Abstract. According to current estimates, atmospheric new particle formation (NPF) produces a large fraction of aerosol particles and cloud condensation nuclei in the Earth's atmosphere, which have implications for health and climate. Despite recent advances, atmospheric NPF is still insufficiently understood in the lower troposphere, especially above the mixed layer (ML). This paper presents new results from co-located airborne and ground-based measurements in a boreal forest environment, showing that many NPF events (∼42 %) appear to start in the topmost part of the residual layer (RL). The freshly formed particles may be entrained into the growing mixed layer (ML) where they continue to grow in size, similar to the aerosol particles formed within the ML. The results suggest that in the boreal forest environment, NPF in the upper RL has an important contribution to the aerosol load in the boundary layer (BL).

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Aerosol particle formation in the upper residual layer

10.5194/acp-2020-923 ◽

2020 ◽

Author(s):

Janne Lampilahti ◽

Katri Leino ◽

Antti Manninen ◽

Pyry Poutanen ◽

Anna Franck ◽

...

Keyword(s):

Boundary Layer ◽

Boreal Forest ◽

Cloud Condensation Nuclei ◽

Large Fraction ◽

Aerosol Particles ◽

Particle Formation ◽

Residual Layer ◽

Forest Environment ◽

Near Surface

Abstract. According to current estimates, atmospheric new particle formation (NPF) produces a large fraction of aerosol particles and cloud condensation nuclei in the earth’s atmosphere, therefore having implications for health and climate. Despite recent advances, atmospheric NPF is still insufficiently understood in the upper parts of the boundary layer (BL). In addition, it is unclear how NPF in upper BL is related to the processes observed in the near-surface layer. The role of the topmost part of the residual layer (RL) in NPF is to a large extent unexplored. This paper presents new results from co-located airborne and ground-based measurements in a boreal forest environment, showing that many NPF events (∼42 %) appear to start in the upper RL. The freshly formed particles may be entrained into the growing mixed layer (ML) where they continue to grow in size, similar to the aerosol particles formed within the ML. The results suggest that in the boreal forest environment, NPF in the upper RL has an important contribution to the aerosol load in the BL.

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Calibration of LACIS as a CCN detector and its use in measuring activation and hygroscopic growth of atmospheric aerosol particles

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-4519-2006 ◽

2006 ◽

Vol 6 (12) ◽

pp. 4519-4527 ◽

Cited By ~ 19

Author(s):

H. Wex ◽

A. Kiselev ◽

M. Ziese ◽

F. Stratmann

Keyword(s):

Sodium Chloride ◽

Wall Temperature ◽

Atmospheric Aerosol ◽

Volume Fraction ◽

Cloud Condensation Nuclei ◽

Aerosol Particles ◽

Urban Aerosol ◽

Hygroscopic Growth ◽

Atmospheric Aerosol Particles ◽

Droplet Activation

Abstract. A calibration for LACIS (Leipzig Aerosol Cloud Interaction Simulator) for its use as a CCN (cloud condensation nuclei) detector has been developed. For this purpose, sodium chloride and ammonium sulfate particles of known sizes were generated and their grown sizes were detected at the LACIS outlet. From these signals, the effective critical super-saturation was derived as a function of the LACIS wall temperature. With this, LACIS is calibrated for its use as a CCN detector. The applicability of LACIS for measurements of the droplet activation, and also of the hygroscopic growth of atmospheric aerosol particles was tested. The activation of the urban aerosol particles used in the measurements was found to occur at a critical super-saturation of 0.46% for particles with a dry diameter of 75 nm, and at 0.42% for 85 nm, respectively. Hygroscopic growth was measured for atmospheric aerosol particles with dry diameters of 150, 300 and 350 nm at relative humidities of 98 and 99%, and it was found that the larger dry particles contained a larger soluble volume fraction of about 0.85, compared to about 0.6 for the 150 nm particles.

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THE EFFECT OF CAVITATION TREATMENT ON THE EXTINGUISHING OF PARTICLES OF OILS IN FUEL BOILERS

Proceedings of the higher educational institutions ENERGY SECTOR PROBLEMS ◽

10.30724/1998-9903-2018-20-9-10-52-59 ◽

2019 ◽

Vol 20 (9-10) ◽

pp. 52-59

Author(s):

M. A. Taymarov ◽

R. V. Akhmetova ◽

S. M. Margulis ◽

L. I. Kasimova

Keyword(s):

Particle Size ◽

Combustion Zone ◽

Consumption Rate ◽

Fuel Oil ◽

Particle Sizes ◽

Oil Consumption ◽

Boiler Efficiency ◽

Large Particles ◽

Oil Particles

The difficulties of burning the watered fuel oil used at the TPP as a reserve fuel for boilers are associated with its preparation by heating to reduce viscosity and the choice of a method of spraying with nozzles into the combustion zone. The quality of the preparation of fuel oil for combustion affecting the boiler efficiency is estimated by the length of the flame, the presence of burning large particles of fuel oil, the injection of coke and unburned particles onto screen and other heat-receiving surfaces. One of the ways to prepare fuel oil for combustion is cavitation treatment, which results in an emulsion consisting of fine micronsized particles. Heating of fuel oil particles after the nozzle in contact with the combustion zone is due to the flow of radiation from the burning torch. Therefore, in this article, the values of the flux density from the torch during the combustion of fuel oil are experimentally determined. The influence of particle size on the burning rate of the fuel oil M100 with the different density of the thermal radiation of the flame. It is found that the effect of cavitation treatment of fuel oil on the combustion rate is most significantly manifested in particle sizes less than 10 microns. For this purpose, the use of hydrodynamic cavitators are preferred at high fuel oil consumption rate.

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Mass transfer effects in hygroscopic measurements of aerosol particles

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-2703-2005 ◽

2005 ◽

Vol 5 (10) ◽

pp. 2703-2712 ◽

Cited By ~ 77

Author(s):

M. N. Chan ◽

C. K. Chan

Keyword(s):

Mass Transfer ◽

Residence Time ◽

Cloud Condensation Nuclei ◽

Aerosol Particles ◽

Literature Survey ◽

Atmospheric Particles ◽

Transfer Effects ◽

Differential Mobility ◽

Scattering Coefficients ◽

Important Concern

Abstract. The tandem differential mobility analyzer (TDMA) has been widely utilized to measure the hygroscopicity of laboratory-generated and atmospheric submicrometer particles. An important concern in investigating the hygroscopicity of the particles is if the particles have attained equilibrium state in the measurements. We present a literature survey to investigate the mass transfer effects in hygroscopicity measurements. In most TDMA studies, a residence time in the order of seconds is used for humidification (or dehumidification). NaCl and (NH4)2SO4 particles are usually used to verify the equilibrium measurements during this residence time, which is presumed to be sufficient for other particles. There have been observations that not all types of submicrometer particles, including atmospheric particles, attain their equilibrium sizes within this time scale. We recommend that experimentation with different residence times be conducted and that the residence time should be explicitly stated in future TDMA measurements. Mass transfer effects may also exist in the measurements of other properties related to the water uptake of atmospheric particles such as relative humidity dependent light scattering coefficients and cloud condensation nuclei activity.

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Observations of Snowmelt Runoff Pathways on a Slope in a Boreal Forest Environment, Lac Laflamme, Quebec

Seasonal Snowcovers: Physics, Chemistry, Hydrology ◽

10.1007/978-94-009-3947-9_27 ◽

1987 ◽

pp. 611-624

Author(s):

Jean Roberge ◽

André P. Plamondon

Keyword(s):

Boreal Forest ◽

Snowmelt Runoff ◽

Forest Environment

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Streaming instability of multiple particle species in protoplanetary disks

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832783 ◽

2018 ◽

Vol 618 ◽

pp. A75 ◽

Cited By ~ 13

Author(s):

Noemi Schaffer ◽

Chao-Chin Yang ◽

Anders Johansen

Keyword(s):

Particle Size ◽

Size Distribution ◽

Protoplanetary Disks ◽

Single Species ◽

Stokes Number ◽

Dust Particles ◽

Particle Sizes ◽

Particle Species ◽

Streaming Instability ◽

Large Particles

The radial drift and diffusion of dust particles in protoplanetary disks affect both the opacity and temperature of such disks, as well as the location and timing of planetesimal formation. In this paper, we present results of numerical simulations of particle-gas dynamics in protoplanetary disks that include dust grains with various size distributions. We have considered three scenarios in terms of particle size ranges, one where the Stokes number τs = 10−1−100, one where τs = 10−4−10−1, and finally one where τs = 10−3−100. Moreover, we considered both discrete and continuous distributions in particle size. In accordance with previous works we find in our multispecies simulations that different particle sizes interact via the gas and as a result their dynamics changes compared to the single-species case. The larger species trigger the streaming instability and create turbulence that drives the diffusion of the solid materials. We measured the radial equilibrium velocity of the system and find that the radial drift velocity of the large particles is reduced in the multispecies simulations and that the small particle species move on average outwards. We also varied the steepness of the size distribution, such that the exponent of the solid number density distribution, dN∕da ∝ a−q, is either q = 3 or q = 4. Overall, we find that the steepness of the size distribution and the discrete versus continuous approach have little impact on the results. The level of diffusion and drift rates are mainly dictated by the range of particle sizes. We measured the scale height of the particles and observe that small grains are stirred up well above the sedimented midplane layer where the large particles reside. Our measured diffusion and drift parameters can be used in coagulation models for planet formation as well as to understand relative mixing of the components of primitive meteorites (matrix, chondrules and CAIs) prior to inclusion in their parent bodies.

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