Integrating Cloud Condensation Nuclei Predictions with Fast Time Resolved Aerosol Instrumentation to Determine the Hygroscopic Properties of Emissions Over Transient Drive Cycles

Abstract. The chemical composition of fine particulate matter (PM2.5), the size distribution and number concentration of aerosol particles (NCN), and the number concentration of cloud condensation nuclei (NCCN) were measured at the northern tip of Taiwan during an intensive observation experiment from April 2017 to March 2018. The parameters of aerosol hygroscopicity (i.e., activation ratio, activation diameter and kappa of CCN) were retrieved from the measurements. Significant variations were found in the hygroscopicity of aerosols (kappa – κ – of 0.18–0.56, for water vapor supersaturation – SS – of 0.12 %–0.80 %), which were subject to various pollution sources, including aged air pollutants originating in eastern and northern China and transported by the Asian continental outflows and fresh particles emitted from local sources and distributed by land–sea breeze circulations as well as produced by processes of new particle formation (NPF). Cluster analysis was applied to the back trajectories of air masses to investigate their respective source regions. The results showed that aerosols associated with Asian continental outflows were characterized by lower NCN and NCCN values and by higher kappa values of CCN, whereas higher NCN and NCCN values with lower kappa values of CCN were observed in the aerosols associated with local air masses. Besides, it was revealed that the kappa value of CCN exhibited a decrease during the early stage of an event of new particle formation, which turned to an increasing trend over the later period. The distinct features in the hygroscopicity of aerosols were found to be consistent with the characteristics in the chemical composition of PM2.5. This study has depicted a clear seasonal characteristic of hygroscopicity and CCN activity under the influence of a complex mixture of pollutants from different regional and/or local pollution sources. Nevertheless, the mixing state and chemical composition of the aerosols critically influence the aerosol hygroscopicity, and further investigations are necessary to elucidate the atmospheric processing involved in the CCN activation in coastal areas.

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The analysis of size-segregated cloud condensation nuclei counter (CCNC) data and its implications for cloud droplet activation

Atmospheric Chemistry and Physics ◽

10.5194/acp-13-10285-2013 ◽

2013 ◽

Vol 13 (20) ◽

pp. 10285-10301 ◽

Cited By ~ 45

Author(s):

M. Paramonov ◽

P. P. Aalto ◽

A. Asmi ◽

N. Prisle ◽

V.-M. Kerminen ◽

...

Keyword(s):

Cloud Condensation Nuclei ◽

Critical Diameter ◽

Cloud Droplet ◽

Condensation Nuclei ◽

Ambient Aerosol ◽

Cloud Processing ◽

Aerosol Mass ◽

Diurnal Patterns ◽

Hygroscopic Properties ◽

Boreal Environment

Abstract. Ambient aerosol, CCN (cloud condensation nuclei) and hygroscopic properties were measured with a size-segregated CCNC (cloud condensation nuclei counter) in a boreal environment of southern Finland at the SMEAR (Station for Measuring Ecosystem-Atmosphere Relations) II station. The instrumental setup operated at five levels of supersaturation S covering a range from 0.1–1% and measured particles with a size range of 20–300 nm; a total of 29 non-consecutive months of data are presented. The median critical diameter Dc ranged from 150 nm at S of 0.1% to 46 nm at S of 1.0%. The median aerosol hygroscopicity parameter κ ranged from 0.41 at S of 0.1% to 0.14 at S of 1.0%, indicating that ambient aerosol in Hyytiälä is less hygroscopic than the global continental or European continental averages. It is, however, more hygroscopic than the ambient aerosol in an Amazon rainforest, a European high Alpine site or a forested mountainous site. A fairly low hygroscopicity in Hyytiälä is likely a result of a large organic fraction present in the aerosol mass comparative to other locations within Europe. A considerable difference in particle hygroscopicity was found between particles smaller and larger than ~100 nm in diameter, possibly pointing out to the effect of cloud processing increasing κ of particles > 100 nm in diameter. The hygroscopicity of the smaller, ~50 nm particles did not change seasonally, whereas particles with a diameter of ~150 nm showed a decreased hygroscopicity in the summer, likely resulting from the increased VOC emissions of the surrounding boreal forest and secondary organic aerosol (SOA) formation. For the most part, no diurnal patterns of aerosol hygroscopic properties were found. Exceptions to this were the weak diurnal patterns of small, ~50 nm particles in the spring and summer, when a peak in hygroscopicity around noon was observed. No difference in CCN activation and hygroscopic properties was found on days with or without atmospheric new particle formation. During all seasons, except summer, a CCN-inactive fraction was found to be present, rendering the aerosol of 75–300 nm in diameter as internally mixed in the summer and not internally mixed for the rest of the year.

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Air mass physiochemical characteristics over New Delhi: impacts on aerosol hygroscopicity and cloud condensation nuclei (CCN) formation

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-6953-2020 ◽

2020 ◽

Vol 20 (11) ◽

pp. 6953-6971 ◽

Cited By ~ 2

Author(s):

Zainab Arub ◽

Sahil Bhandari ◽

Shahzad Gani ◽

Joshua S. Apte ◽

Lea Hildebrandt Ruiz ◽

...

Keyword(s):

Chemical Composition ◽

Size Distribution ◽

Cloud Condensation Nuclei ◽

Chemical Properties ◽

Industrial Emissions ◽

Condensation Nuclei ◽

Aerosol Composition ◽

Time Resolved ◽

Air Mass ◽

Air Masses

Abstract. Delhi is a megacity subject to high local anthropogenic emissions and long-range transport of pollutants. This work presents for the first time time-resolved estimates of hygroscopicity parameter (κ) and cloud condensation nuclei (CCN), spanning for more than a year, derived from chemical composition and size distribution data. As a part of the Delhi Aerosol Supersite (DAS) campaign, the characterization of aerosol composition and size distribution was conducted from January 2017 to March 2018. Air masses originating from the Arabian Sea (AS), Bay of Bengal (BB), and southern Asia (SA) exhibited distinct characteristics of time-resolved sub-micron non-refractory PM1 (NRPM1) species, size distributions, and CCN number concentrations. The SA air mass had the highest NRPM1 loading with high chloride and organics, followed by the BB air mass, which was more contaminated than AS, with a higher organic fraction and nitrate. The primary sources were identified as biomass-burning, thermal power plant emissions, industrial emissions, and vehicular emissions. The average hygroscopicity parameter (κ), calculated by the mixing rule, was approximately 0.3 (varying between 0.13 and 0.77) for all the air masses (0.32±0.06 for AS, 0.31±0.06 for BB, and 0.32±0.10 for SA). The diurnal variations in κ were impacted by the chemical properties and thus source activities. The total, Aitken, and accumulation mode number concentrations were higher for SA, followed by BB and AS. The mean values of estimated CCN number concentration (NCCN; 3669–28926 cm−3) and the activated fraction (af; 0.19–0.87), for supersaturations varying from 0.1 % to 0.8 %, also showed the same trend, implying that these were highest in SA, followed by those in BB and then those in AS. The size turned out to be more important than chemical composition directly, and the NCCN was governed by either the Aitken or accumulation modes, depending upon the supersaturation (SS) and critical diameter (Dc). af was governed mainly by the geometric mean diameter (GMD), and such a high af (0.71±0.14 for the most dominant sub-branch of the SA air mass – R1 – at 0.4 % SS) has not been seen anywhere in the world for a continental site. The high af was a consequence of very low Dc (25–130 nm, for SS ranging from 0.1 % to 0.8 %) observed for Delhi. Indirectly, the chemical properties also impacted CCN and af by impacting the diurnal patterns of Aitken and accumulation modes, κ and Dc. The high-hygroscopic nature of aerosols, high NCCN, and high af can severely impact the precipitation patterns of the Indian monsoon in Delhi, impact the radiation budget, and have indirect effects and need to be investigated to quantify this impact.

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Cloud condensation nuclei activity of fresh primary and aged biomass burning aerosol

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-7285-2012 ◽

2012 ◽

Vol 12 (15) ◽

pp. 7285-7293 ◽

Cited By ~ 81

Author(s):

G. J. Engelhart ◽

C. J. Hennigan ◽

M. A. Miracolo ◽

A. L. Robinson ◽

S. N. Pandis

Keyword(s):

Biomass Burning ◽

Cloud Condensation Nuclei ◽

Organic Aerosol ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

A Value ◽

Biomass Burning Aerosol ◽

Photochemical Processing ◽

Photochemical Aging ◽

Aerosol Emissions

Abstract. We quantify the hygroscopic properties of particles freshly emitted from biomass burning and after several hours of photochemical aging in a smog chamber. Values of the hygroscopicity parameter, κ, were calculated from cloud condensation nuclei (CCN) measurements of emissions from combustion of 12 biomass fuels commonly burned in North American wildfires. Prior to photochemical aging, the κ of the fresh primary aerosol varied widely, between 0.06 (weakly hygroscopic) and 0.6 (highly hygroscopic). The hygroscopicity of the primary aerosol was positively correlated with the inorganic mass fraction of the particles. Photochemical processing reduced the range of κ values to between 0.08 and 0.3. The changes in κ were driven by the photochemical production of secondary organic aerosol (SOA). SOA also contributed to growth of particles formed during nucleation events. Analysis of the nucleation mode particles enabled the first direct quantification of the hygroscopicity parameter κ for biomass burning SOA, which was on average 0.11, similar to values observed for biogenic SOA. Although initial CCN activity of biomass burning aerosol emissions are highly variable, after a few hours of photochemical processing κ converges to a value of 0.2 ± 0.1. Therefore, photochemical aging reduces the variability of biomass burning CCN κ, which should simplify analysis of the potential effects of biomass burning aerosol on climate.

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Size-resolved aerosol water uptake and cloud condensation nuclei measurements as measured above a Southeast Asian rainforest during OP3

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-11157-2011 ◽

2011 ◽

Vol 11 (21) ◽

pp. 11157-11174 ◽

Cited By ~ 26

Author(s):

M. Irwin ◽

N. Robinson ◽

J. D. Allan ◽

H. Coe ◽

G. McFiggans

Keyword(s):

Water Uptake ◽

Radiative Forcing ◽

Tropical Rainforest ◽

Fine Particles ◽

Hydrological Cycle ◽

Cloud Condensation Nuclei ◽

Tropical Atmosphere ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

Diameter Range

Abstract. The influence of the properties of fine particles on the formation of clouds and precipitation in the tropical atmosphere is of primary importance to their impacts on radiative forcing and the hydrological cycle. Measurements of aerosol number size distribution, hygroscopicity in both sub- and supersaturated regimes and composition were taken between March and July 2008 in the tropical rainforest in Borneo, Malaysia, marking the first study of this type in an Asian tropical rainforest. Hygroscopic growth factors (GF) at 90 % relative humidity (RH) for the dry diameter range D0 = 32–258 nm, supersaturated water uptake behaviour for the dry diameter range D0 = 45–300 nm and aerosol chemical composition were simultaneously measured using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA), a Droplet Measurement Technologies Cloud Condensation Nuclei counter (CCNc) and an Aerodyne Aerosol Mass Spectrometer (AMS) respectively. The hygroscopicity parameter κ was derived from both CCNc and HTDMA measurements, with the resulting values of κ ranging from 0.05–0.37, and 0.17–0.37, respectively. Although the total range of κ values is in good agreement, there are inconsistencies between CCNc and HTDMA derived κ values at different dry diameters. Results from a study with similar methodology performed in the Amazon rainforest report values for κ within a similar range to those reported in this work, indicating that the aerosol as measured from both sites shows similar hygroscopic properties. However, the derived number of cloud condensation nuclei (NCCN) were much higher in the present experiment than the Amazon, resulting in part from the increased total particle number concentrations observed in the Bornean rainforest. This contrast between the two environments may be of substantial importance in describing the impacts of particles in the tropical atmosphere.

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A synthesis of cloud condensation nuclei counter (CCNC) measurements within the EUCAARI network

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-12211-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 12211-12229 ◽

Cited By ~ 21

Author(s):

M. Paramonov ◽

V.-M. Kerminen ◽

M. Gysel ◽

P. P. Aalto ◽

M. O. Andreae ◽

...

Keyword(s):

Size Distribution ◽

Cloud Condensation Nuclei ◽

Number Concentration ◽

West Germany ◽

Aerosol Size Distribution ◽

Spatial And Temporal Variability ◽

Condensation Nuclei ◽

Aerosol Cloud ◽

Hygroscopic Properties ◽

South West

Abstract. Cloud condensation nuclei counter (CCNC) measurements performed at 14 locations around the world within the European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) framework have been analysed and discussed with respect to the cloud condensation nuclei (CCN) activation and hygroscopic properties of the atmospheric aerosol. The annual mean ratio of activated cloud condensation nuclei (NCCN) to the total number concentration of particles (NCN), known as the activated fraction A, shows a similar functional dependence on supersaturation S at many locations – exceptions to this being certain marine locations, a free troposphere site and background sites in south-west Germany and northern Finland. The use of total number concentration of particles above 50 and 100 nm diameter when calculating the activated fractions (A50 and A100, respectively) renders a much more stable dependence of A on S; A50 and A100 also reveal the effect of the size distribution on CCN activation. With respect to chemical composition, it was found that the hygroscopicity of aerosol particles as a function of size differs among locations. The hygroscopicity parameter κ decreased with an increasing size at a continental site in south-west Germany and fluctuated without any particular size dependence across the observed size range in the remote tropical North Atlantic and rural central Hungary. At all other locations κ increased with size. In fact, in Hyytiälä, Vavihill, Jungfraujoch and Pallas the difference in hygroscopicity between Aitken and accumulation mode aerosol was statistically significant at the 5 % significance level. In a boreal environment the assumption of a size-independent κ can lead to a potentially substantial overestimation of NCCN at S levels above 0.6 %. The same is true for other locations where κ was found to increase with size. While detailed information about aerosol hygroscopicity can significantly improve the prediction of NCCN, total aerosol number concentration and aerosol size distribution remain more important parameters. The seasonal and diurnal patterns of CCN activation and hygroscopic properties vary among three long-term locations, highlighting the spatial and temporal variability of potential aerosol–cloud interactions in various environments.

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Metal complexation inhibits the effect of oxalic acid in aerosols as cloud condensation nuclei (CCN)

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-27099-2010 ◽

2010 ◽

Vol 10 (11) ◽

pp. 27099-27134 ◽

Cited By ~ 1

Author(s):

T. Furukawa ◽

Y. Takahashi

Keyword(s):

Oxalic Acid ◽

Cloud Condensation Nuclei ◽

Organic Aerosols ◽

Water Soluble ◽

Cooling Effect ◽

Radiation Balance ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

Metal Oxalate ◽

Oxalate Complexes

Abstract. Atmospheric aerosols have both a direct and an indirect cooling effect that influences the radiative balance at the Earth's surface. It has been estimated that the degree of cooling is large enough to cancel the warming effect of carbon dioxide. Among the cooling factors, secondary organic aerosols (SOA) play a key role in the solar radiation balance in the troposphere as SOA can act as cloud condensation nuclei (CCN) and extend the lifespan of clouds because of their high hygroscopic and water soluble nature. Oxalic acid is one of the major components of SOA, and is produced via several formation pathways in the atmosphere. However, it is not certain whether oxalic acid exists as free oxalic acid or as metal oxalate complexes in aerosols, although there is a marked difference in their solubility in water and their hygroscopicity. We employed X-ray absorption fine structure spectroscopy to characterize the calcium (Ca) and zinc (Zn) in aerosols collected at Tsukuba in Japan with fractionation based on particle size using an impactor aerosol sampler. It was shown that 10–60% and 20–100% of the total Ca and Zn in the finer particles (<2.1 μm) were present as Ca and Zn oxalate complexes, respectively. Oxalic acid can act as CCN because of its hygroscopic properties, while metal complexes are not hygroscopic, and so cannot be CCN. Based on the concentration of noncomplexed and metal-complexed oxalate species, we found that most of the oxalic acid is present as metal oxalate complexes in the aerosols, suggesting that oxalic acid does not act as CCN in the atmosphere. Similar results are expected for other dicarboxylic acids, such as malonic and succinic acids. Thus, it is possible that the cooling effect of organic aerosols assumed in various climate modeling studies is overestimated because of the lack of information on metal oxalate complexes in aerosols.

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Cloud condensation nuclei spectra derived from size distributions and hygroscopic properties of the aerosol in coastal south-west Portugal during ACE-2

Tellus B ◽

10.1034/j.1600-0889.2003.00041.x ◽

2003 ◽

Vol 55 (1) ◽

pp. 35-53 ◽

Cited By ~ 23

Author(s):

ULRIKE DUSEK ◽

DAVID S. COVERT ◽

ALFRED WIEDENSOHLER ◽

CHRISTIAN NEUSUSS ◽

DIANA WEISE ◽

...

Keyword(s):

Cloud Condensation Nuclei ◽

Size Distributions ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

South West

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Size-resolved aerosol water uptake and cloud condensation nuclei measurements as measured above a Southeast Asian rainforest during OP3

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-3117-2011 ◽

2011 ◽

Vol 11 (1) ◽

pp. 3117-3159 ◽

Cited By ~ 4

Author(s):

M. Irwin ◽

N. Robinson ◽

J. D. Allan ◽

H. Coe ◽

G. McFiggans

Keyword(s):

Relative Humidity ◽

Water Uptake ◽

Radiative Forcing ◽

Tropical Rainforest ◽

Hydrological Cycle ◽

Cloud Condensation Nuclei ◽

Tropical Atmosphere ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

Diameter Range

Abstract. The influence of the properties of fine particles on the formation of clouds and precipitation in the tropical atmosphere is of primary importance to their impacts on radiative forcing and the hydrological cycle. Measurements of aerosol number size distribution, hygroscopicity in both sub- and supersaturated regimes and composition were taken between March and July 2008 in the tropical rainforest in Borneo, Malaysia, marking the first study of this type in an Asian tropical rainforest. Hygroscopic growth factors (GF) at 90% relative humidity (RH) for the dry diameter range D0=32–258 nm, supersaturated water uptake behaviour for the dry diameter range D0=20–300 nm and aerosol chemical composition were simultaneously measured using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA), a Droplet Measurement Technologies Cloud Condensation Nuclei counter (CCNc) and an Aerodyne Aerosol Mass Spectrometer (AMS), respectively. The derived hygroscopicty parameter κ ranged from between 0.05–0.37 for the supersaturation range 0.11–0.73% compared to those between 0.17–0.37 for measurements performed at a relative humidity of 90%. In contrast, results from a study with similar methodology performed in the Amazon basin report more similar values for κ, indicating that the aerosol as measured from both sites shows similar hygroscopic properties. However, the derived number of cloud condensation nuclei (NCCN) were much higher than those measured in the Amazon, due to the higher particle number concentrations in the rainforests of Borneo. This first contrast between the two environments may be of substantial importance in describing the impacts of particles in the tropical atmosphere.

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Hygroscopic properties and cloud condensation nuclei activation of limonene-derived organosulfates and their mixtures with ammonium sulfate

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-14071-2015 ◽

2015 ◽

Vol 15 (24) ◽

pp. 14071-14089 ◽

Cited By ~ 26

Author(s):

A. M. K. Hansen ◽

J. Hong ◽

T. Raatikainen ◽

K. Kristensen ◽

A. Ylisirniö ◽

...

Keyword(s):

Surface Tension ◽

Ammonium Sulfate ◽

Cloud Condensation Nuclei ◽

Pure Water ◽

Particle Diameter ◽

Droplet Surface ◽

Chemical Compositions ◽

Condensation Nuclei ◽

Hygroscopic Properties ◽

Wide Range

Abstract. Organosulfates have been observed as constituents of atmospheric aerosols in a wide range of environments; however their hygroscopic properties remain uncharacterised. Here, limonene-derived organosulfates with a molecular weight of 250 Da (L-OS 250) were synthesised and used for simultaneous measurements with a hygroscopicity tandem differential mobility analyser (H-TDMA) and a cloud condensation nuclei counter (CCNC) to determine the hygroscopicity parameter, κ, for pure L-OS 250 and mixtures of L-OS 250 with ammonium sulfate (AS) over a wide range of humidity conditions. The κ values derived from measurements with H-TDMA decreased with increasing particle dry diameter for all chemical compositions investigated, indicating that κH-TDMA depends on particle diameter and/or surface effects; however, it is not clear if this trend is statistically significant. For pure L-OS 250, κ was found to increase with increasing relative humidity, indicating dilution/solubility effects to be significant. Discrepancies in κ between the sub- and supersaturated measurements were observed for L-OS 250, whereas κ of AS and mixed L-OS 250/AS were similar. This discrepancy was primarily ascribed to limited dissolution of L-OS 250 at subsaturated conditions. In general, hygroscopic growth factor, critical particle diameter and κ for the mixed L-OS 250/AS particles converged towards the values of pure AS for mixtures with ≥ 20 % w / w AS. Surface tension measurements of bulk aqueous L-OS 250/AS solutions showed that L-OS 250 was indeed surface active, as expected from its molecular structure, decreasing the surface tension of solutions with 24 % from the pure water value at a L-OS 250 concentration of 0.0025 mol L−1. Based on these surface tension measurements, we present the first concentration-dependent parametrisation of surface tension for aqueous L-OS 250, which was implemented to different process-level models of L-OS 250 hygroscopicity and CCN activation. The values of κ obtained from the measurements were compared with κ calculated applying the volume additive Zdanovskii–Stokes–Robinson mixing rule, as well as κ modelled from equilibrium Köhler theory with different assumptions regarding L-OS 250 bulk-to-surface partitioning and aqueous droplet surface tension. This study is to our knowledge the first to investigate the hygroscopic properties and surface activity of L-OS 250; hence it is an important first step towards understanding the atmospheric impact of organosulfates.

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