How do air ions reflect variations in ionising radiation in the lower atmosphere in a boreal forest?

Abstract. Most of the ion production in the atmosphere is attributed to ionising radiation. In the lower atmosphere, ionising radiation consists mainly of the decay emissions of radon and its progeny, gamma radiation of the terrestrial origin as well as photons and elementary particles of cosmic radiation. These types of radiation produce ion pairs via the ionisation of nitrogen and oxygen as well as trace species in the atmosphere, the rate of which is defined as the ionising capacity. Larger air ions are produced out of the initial charge carriers by processes such as clustering or attachment to pre-existing aerosol particles. This study aimed (1) to identify the key factors responsible for the variability in ionising radiation and in the observed air ion concentrations, (2) to reveal the linkage between them and (3) to provide an in-depth analysis into the effects of ionising radiation on air ion formation, based on measurement data collected during 2003–2006 from a boreal forest site in southern Finland. In general, gamma radiation dominated the ion production in the lower atmosphere. Variations in the ionising capacity came from mixing layer dynamics, soil type and moisture content, meteorological conditions, long-distance transportation, snow cover attenuation and precipitation. Slightly similar diurnal patterns to variations in the ionising capacity were observed in air ion concentrations of the cluster size (0.8–1.7 nm in mobility diameters). However, features observed in the 0.8–1 nm ion concentration were in good connection to variations of the ionising capacity. Further, by carefully constraining perturbing variables, a strong dependency of the cluster ion concentration on the ionising capacity was identified, proving the functionality of ionising radiation in air ion production in the lower atmosphere. This relationship, however, was only clearly observed on new particle formation (NPF) days, possibly indicating that charges after being born underwent different processes on NPF days and non-event days and also that the transformation of newly formed charges to cluster ions occurred in a shorter timescale on NPF days than on non-event days.

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From ionising radiation to air ion formation in the lower atmosphere

10.5194/acp-2016-440 ◽

2016 ◽

Author(s):

Xuemeng Chen ◽

Veli-Matti Kerminen ◽

Jussi Paatero ◽

Pauli Paasonen ◽

Hanna E. Manninen ◽

...

Keyword(s):

Gamma Radiation ◽

Ionising Radiation ◽

Ion Concentration ◽

Lower Atmosphere ◽

Forest Site ◽

Long Distance ◽

Ion Concentrations ◽

Ion Formation ◽

Depth Analysis ◽

Ion Production

Abstract. Most of the ion production in the atmosphere is attributed to ionising radiation. In the lower atmosphere, ionising radiation consists mainly of the decay emissions of radon and its progeny, gamma radiation of the terrestrial origin as well as photons and elementary particles of cosmic radiation. These types of radiation produce ion pairs via the ionisation of nitrogen and oxygen as well as trace species in the atmosphere, the rate of which is defined as the ionising capacity. Larger air ions are produced out of the initial charge carriers by processes, such as clustering or attachment to pre-existing aerosol particles. This study aimed 1) to identify the key factors responsible for the variability in ionising radiation and in the observed air ion concentrations, 2) to reveal the linkage between them, and 3) to provide an in-depth analysis into the effects of ionising radiation on air ion formation, based on measurement data collected during 2003–2006 from a boreal forest site in southern Finland. In general, gamma radiation dominated the ion production in the lower atmosphere. Variations in the ionising capacity came from mixing layer dynamics, soil type and moisture content, meteorological conditions, long-distance transportation, snow cover attenuation and precipitation. Similar diurnal patterns to variations in the ionising capacity were observed in air ion concentrations of the cluster size (0.8–1.7 nm in mobility diameters). Clear promotion effects of the ionising radiation on air ion production were demonstrated. Typically, features observed in the 0.8–1 nm ion concentration were in connection to variations of the ionising capacity. Further by carefully constraining perturbing variables, a clear relationship was also identifiable between the cluster ion concentration and the ionising capacity, proving the functionality of ionising radiation in air ion production in the lower atmosphere.

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Variation and balance of positive air ion concentrations in a boreal forest

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-655-2008 ◽

2008 ◽

Vol 8 (3) ◽

pp. 655-675 ◽

Cited By ~ 34

Author(s):

U. Hõrrak ◽

P. P. Aalto ◽

J. Salm ◽

K. Komsaare ◽

H. Tammet ◽

...

Keyword(s):

Steady State ◽

Boreal Forest ◽

Correlation Coefficient ◽

Aerosol Particles ◽

Coniferous Forest ◽

Ionization Rate ◽

Ion Concentration ◽

Air Ions ◽

Ion Concentrations ◽

Charged Aerosol

Abstract. Air ions are characterized on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. The air ions were discriminated as small ions (charged molecular aggregates of the diameter of less than 2.5 nm), intermediate ions (charged aerosol particles of the diameter of 2.5–8 nm), and large ions (charged aerosol particles of the diameter of 8–20 nm). Statistical characteristics of the ion concentrations and the parameters of ion balance in the atmosphere are presented separately for the nucleation event days and non-event days. In the steady state, the ionization rate is balanced with the loss of small ions, which is expressed as the product of the small ion concentration and the ion sink rate. The widely known sinks of small ions are the recombination with small ions of opposite polarity and attachment to aerosol particles. The dependence of small ion concentration on the concentration of aerosol particles was investigated applying a model of the bipolar diffusion charging of particles by small ions. When the periods of relative humidity above 95% and wind speed less than 0.6 m s−1 were excluded, then the small ion concentration and the theoretically calculated small ion sink rate were closely negatively correlated (correlation coefficient −87%). However, an extra ion loss term of the same magnitude as the ion loss onto aerosol particles is needed for a quantitative explanation of the observations. This term is presumably due to the small ion deposition on coniferous forest. The hygroscopic growth correction of the measured aerosol particle size distributions was also found to be necessary for the proper estimation of the ion sink rate. In the case of nucleation burst events, the concentration of small positive ions followed the general balance equation, no extra ion loss in addition to the deposition on coniferous forest was detected, and the hypothesis of the conversion of ions into particles in the process of ion-induced nucleation was not proved. The estimated average ionization rate of the air at the Hyytiälä station in early spring, when the ground was partly covered with snow, was about 6 ion pairs cm−3 s−1. The study of the charging state of nanometer aerosol particles (diameter 2.5–8 nm) in the atmosphere revealed a strong correlation (correlation coefficient 88%) between the concentrations of particles neutralized in the aerosol spectrometer and naturally positively charged particles (air ions) during nucleation bursts. The charged fraction of particles varied from 3% to 6% in accordance with the hypothesis that the particles are quasi-steady state charged.

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Characterization of air ions in boreal forest air during BIOFOR III campaign

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-2749-2005 ◽

2005 ◽

Vol 5 (3) ◽

pp. 2749-2790 ◽

Cited By ~ 4

Author(s):

U. Hõrrak ◽

P. P. Aalto ◽

J. Salm ◽

J. M. Mäkelä ◽

L. Laakso ◽

...

Keyword(s):

Boreal Forest ◽

Correlation Coefficient ◽

Aerosol Particles ◽

Ion Pairs ◽

Ion Concentration ◽

Cluster Ions ◽

Statistical Characteristics ◽

Nucleation Event ◽

Air Ions ◽

20 Nm

Abstract. The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. Statistical characteristics of the concentrations of cluster ions, two classes of aerosol ions of the sizes of 2.5–8 nm and 8–ca 20 nm and the quantities that determine the balance of small ions in the atmosphere have been given for the nucleation event days and non-event days. The dependence of small ion concentration on the ion loss (sink) due to aerosol particles was investigated applying a model of bipolar diffusion charging of particles by small ions. The small ion concentration and the ion sink were closely correlated (correlation coefficient 87%) when the fog events and the hours of high relative humidity (above 97%), as well as nocturnal calms and weak wind (wind speed<0.6 m s-1 had been excluded. In the case of nucleation burst events, variations in the concentration of small positive ions were in accordance with the changes caused by the ion sink due to aerosols; no clear indication of positive ion depletion by ion-induced nucleation was found. The estimated average ionization rate of air at the Hyytiälä station in early spring, when the ground was partly covered with snow, was about 4.8 ion pairs cm-3 s-1. The study of the charging state of nanometer aerosol particles (2.5–8 nm) revealed a strong correlation (correlation coefficient 88%) between the concentrations of particles and their charged fraction (positive air ions) during nucleation bursts. The estimated charged fraction of particles, which varied from 3% to 6% considering various nucleation event days, confirms that these particles are almost quasi-steady state charged. Also the particles and air ions in the size range of 8–ca 20 nm showed a good qualitative consistency; the correlation coefficient was 92%.

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Characterization of positive air ions in boreal forest air at the Hyytiälä SMEAR station

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-9465-2007 ◽

2007 ◽

Vol 7 (4) ◽

pp. 9465-9517 ◽

Cited By ~ 5

Author(s):

U. Hõrrak ◽

P. P. Aalto ◽

J. Salm ◽

K. Komsaare ◽

H. Tammet ◽

...

Keyword(s):

Boreal Forest ◽

Correlation Coefficient ◽

Aerosol Particles ◽

Ion Pairs ◽

Coniferous Forest ◽

Ion Concentration ◽

Statistical Characteristics ◽

Nucleation Event ◽

Air Ions ◽

20 Nm

Abstract. The behavior of the concentration of positive small (or cluster) air ions and naturally charged nanometer aerosol particles (aerosol ions) has been studied on the basis of measurements carried out in a boreal forest at the Hyytiälä SMEAR station, Finland, during the BIOFOR III campaign in spring 1999. Statistical characteristics of the concentrations of cluster ions, two classes of aerosol ions of the sizes of 2.5–8 nm and 8–ca. 20 nm and the quantities that determine the balance of small ions in the atmosphere have been given for the nucleation event days and non-event days. The dependence of small ion concentration on the ion loss (sink) due to aerosol particles was investigated applying a model of bipolar diffusion charging of particles by small ions. The small ion concentration and the ion sink were closely correlated (correlation coefficient –87%) when the fog events and the hours of high relative humidity (above 95%), as well as nocturnal calms and weak wind (wind speed <0.6 m s−1) had been excluded. However, an extra ion loss term presumably due to small ion deposition on coniferous forest with a magnitude equal to the average ion loss to pre-existing particles is needed to explain the observations. Also the hygroscopic growth correction of measured aerosol particle size distributions was found to be necessary for proper estimation of the ion sink. In the case of nucleation burst events, variations in the concentration of small positive ions were in accordance with the changes caused by the ion sink due to aerosols; no clear indication of positive ion depletion by ion-induced nucleation was found. The estimated average ionization rate of the air at the Hyytiälä station in early spring, when the ground was partly covered with snow, was about 6 ion pairs cm−3 s−1. The study of the charging state of nanometer aerosol particles (2.5–8 nm) revealed a strong correlation (correlation coefficient 88%) between the concentrations of particles and positively charged particles (positive air ions) during nucleation bursts. The estimated charged fraction of particles, which varied from 3% to 6% considering various nucleation event days, confirms that these particles are almost quasi-steady state charged. Also the particles and air ions in the size range of 8–ca. 20 nm showed a good qualitative consistency; the correlation coefficient was 92%.

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Investigation on the role of elevated gamma radiation in ion production during precipitation

10.5194/egusphere-egu21-11909 ◽

2021 ◽

Author(s):

Xuemeng Chen ◽

Susana Barbosa ◽

Jussi Paatero ◽

Markku Kulmala ◽

Heikki Junninen

Keyword(s):

Gamma Radiation ◽

Large Scale ◽

Size Range ◽

Aerosol Particles ◽

Particle Formation ◽

Precipitation Intensity ◽

Ion Concentration ◽

Atmospheric Measurements ◽

Air Ions ◽

Development Fund

Air ions are ubiquitous in the atmosphere. These charge carriers can be found in various forms as charged molecules, nanoclusters as well as aerosol particles. The population of air ions normally concentrates in the cluster size range (0.8 &#8211; 1.7 nm in mobility equivalent diameters) in the absence of particle formation processes. A concentration burst in the intermediate size range (1.7 &#8211; 7 nm) can be typically observed during atmospheric new particle formation (NPF) and in precipitation episodes 1. Contrary to the intermediate ions formed during NPF that favour growth to larger sizes, intermediate ion bursts resulting from precipitation tend to shrink 2,3. The production of intermediate ions during precipitation has been attributed to the Lenard effect and they are usually referred to as the balloelectric ions 3.During precipitation the rain-out and wash-out of radon progeny increase the gamma dose at ground level 4. Being a type of ionising radiation, gamma creates positive and negative charges in the air. These charges are either lost in recombination or transformed into air ions. It is therefore interesting to understand whether the precipitation-associated elevation in gamma radiation plays any role in forming or neutralising the balloelectric ions. At SMEAR II station in Hyyti&#228;l&#228;, Finland 5, we have conducted measurements of air ions, gamma radiation, precipitation together with other meteorological parameters. A similar establishment of the measurement set stands also at SMEAR Estonia station in Jarvselj&#228;, Estonia 6. The data collected at Hyyti&#228;l&#228; from 2017.7 to 2018.8 show that the intermediate ion concentration correlates with rainfall only when the precipitation intensity is greater than 1 mm/h. For milder rainfall with the precipitation intensity being 0.1-1 mm/h, the intermediate ion concentration increases with an increase in the gamma counts. The work is under progress and we intend to extend the analysis to Jarvselj&#228; data for a comprehensive understanding of the observations.Acknowledgements: This work received financial supports from European Regional Development Fund (project MOBTT42) under the Mobilitas Pluss programme and from Estonian Research Council project PRG714.References:1. Tammet, H., Komsaare, K. & H&#245;rrak, U. Intermediate ions in the atmosphere. Atmospheric Research 135-136, 263-273, doi:10.1016/j.atmosres.2012.09.009 (2014).2. H&#245;rrak, U. et al. Formation of Charged Nanometer Aerosol Particles Associated with Rainfall: Atmospheric Measurements and Lab Experiment. Report Series in Aerosol Science 80, 180-185 (2006).3. Tammet, H., H&#245;rrak, U. & Kulmala, M. Negatively charged nanoparticles produced by splashing of water. Atmos. Chem. Phys. 9, 357&#8211;367 (2009).4. Paatero, J. & Hatakka, J. Wet deposition efficiency of short-lived radon-222 progeny in central Finland. Boreal Env. Res. 4, 285-293 (1999).5. Hari, P. & Kulmala, M. Station for measuring ecosystem-atmosphere relations (SMEAR II). Boreal Environ. Res. 10, 315-322 (2005).6. Noe, S. M. et al. SMEAR Estonia: Perspectives of a large-scale forest ecosystem &#8211; atmosphere research infrastructure. Forestry Studies 63, doi:10.1515/fsmu-2015-0009 (2015).

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Chemical changes in simulated raindrops following contact with leaves of four boreal forest species

Canadian Journal of Botany ◽

10.1139/b88-332 ◽

1988 ◽

Vol 66 (12) ◽

pp. 2445-2451 ◽

Cited By ~ 9

Author(s):

Brigitte A. Gaber ◽

Thomas C. Hutchinson

Keyword(s):

Boreal Forest ◽

Dry Deposition ◽

Ion Concentration ◽

Forest Species ◽

Ion Concentrations ◽

Cornus Canadensis ◽

Rapid Changes ◽

Maianthemum Canadense ◽

Forest Plant Species

Simulated raindrops of pH 5.6 or 3.2 were sprayed on four boreal forest plant species in situ, and raindrops were subsequently collected from their leaves for chemical analysis. The purpose was to understand better the changes involved in foliar neutralisation of acidic raindrops. The species used were Cornus canadensis, Aralia nudicaulis, Maianthemum canadense, and Acer spicatum. Samples were analysed for Ca2+, Mg2+, Na+, K+, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], Cl−, and F−, as well as pH. Changes in leaf raindrop ion concentrations were greater when sprayed with the pH 3.2 than with the pH 5.6 rain. Both increases and decreases in ion concentration were found, indicating leaching and (or) dissolution of particulates on the leaf or retention by the canopy, respectively. Rapid changes in ion concentrations suggest surface deposits play an important role in leaf raindrop neutralisation. Increases in [Ca2+] and [Mg2+] in raindrops with greater neutralisation are evidence that cation exchange may also be occurring (r2 = 0.170 and 0.321, respectively, at pH 3.2; p < 0.01). There were significant negative correlations between changes in [H+] and changes in[Formula: see text], [Formula: see text], and [Formula: see text] (r2 = 0.562, 0.525, and 0.297, respectively, at pH 3.2;p < 0.01). Most of the other ions measured also showed significant correlations with changes in [H+], but generally the correlation could account for only a small percentage of the observed results (low r2). Dry deposition was also measured.

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Effect of Environmental Factors on Air Ion Concentration

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2015vol2.241 ◽

2015 ◽

Vol 2 ◽

pp. 274

Author(s):

Andris Skromulis ◽

Juris Breidaks

Keyword(s):

Environmental Factors ◽

Ion Concentration ◽

Physical Parameters ◽

Urban Air ◽

Regression Equations ◽

Air Ions ◽

Atmospheric Air ◽

Ion Concentrations ◽

Air Ion Concentration ◽

Ion Size

The paper discusses and analyzes the effect of environmental factors on ion concentrations in urban air. Statistically mathematical method was used to analyze the measurements of air ion concentration collected in a period of several months, with ion size ranging from 0.75 to 36.6 nm. As environmental factors related to air ions, the following chemical and physical parameters of the atmospheric air were analyzed: CO, NO, NO2, NOx, SO2, O3, PM10, PM2.5, temperature, relative humidity, wind speed and direction. When analyzing data in this combination, there is often a problem of multicollinearity between air chemical and physical parameters. This paper addresses this problem by using the component regression. Regression equations were elaborated to understand the dependence of concentrations of various classes of positive and negative air ions on chemical and physical parameters of the air.

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Thermal stability of ribosomes from a thermophilic and a mesophilic fungus

Canadian Journal of Microbiology ◽

10.1139/m73-123 ◽

1973 ◽

Vol 19 (6) ◽

pp. 761-763 ◽

Cited By ~ 6

Author(s):

H. M. Miller ◽

M. G. Shepherd

Keyword(s):

Thermal Stability ◽

Ion Concentration ◽

Magnesium Ion ◽

Penicillium Notatum ◽

Ribosomal Subunits ◽

Ion Concentrations ◽

Thermal Stability Of

Ribosomes and ribosomal subunits from the thermophile Penicillium duponti were found to be more thermostable than the corresponding particles from the mesophile Penicillium notatum. The thermostability of the ribosomes from both organisms was dependent on magnesium ion concentration. The dissociation of the 80-S ribosomes into 60-S and 40-S subunits occurred at higher magnesium ion concentrations for the mesophile than the thermophile.

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Measurements and correlations between several atmospheric parameters

Facta universitatis - series Physics Chemistry and Technology ◽

10.2298/fupct0801099k ◽

2008 ◽

Vol 6 (1) ◽

pp. 99-104 ◽

Cited By ~ 2

Author(s):

Predrag Kolarz ◽

Dusan Filipovic

Keyword(s):

Relative Humidity ◽

Inverse Correlation ◽

Weather Conditions ◽

Atmospheric Parameters ◽

Air Ions ◽

Ion Concentrations ◽

Humidity Measurements ◽

A Site ◽

Made In ◽

Strong Inverse Correlation

Diurnal atmospheric air-ion concentrations have been investigated at a site where synchronous aerosol, ozone, temperature and relative humidity measurements were also made. Air-ions, temperature and relative humidity were measured with Gerdien type Cylindrical Detector of Air-Ions (CDI-06) made in the Institute of Physics, Belgrade. Ozone and aerosols were measured with commercial instruments owned by the Institute of Public Health, Belgrade. Typical daily variations of the measured parameters were analyzed and showed that air-ions of both signs and ozone are positively correlated, while aerosols show strong inverse correlation with air-ions. Also, concentrations of air-ions and ozone are decreasing with temperature while aerosol concentration and humidity are increasing. These processes could be explained concerning properties of the specified parameters, measuring place properties and weather conditions.

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Local mechanisms of phase-dependent postsynaptic modifications of NMDA-induced oscillations in the abducens motoneurons: a simulation study

Journal of Neurophysiology ◽

10.1152/jn.1996.76.2.1015 ◽

1996 ◽

Vol 76 (2) ◽

pp. 1015-1024 ◽

Cited By ~ 2

Author(s):

I. L. Kopysova ◽

S. M. Korogod ◽

J. Durand ◽

S. Tyc-Dumont

Keyword(s):

Synaptic Input ◽

Pattern Generation ◽

Ion Concentration ◽

Extracellular Potassium ◽

Pump System ◽

Voltage Gated ◽

Ion Concentrations ◽

Concentration Changes ◽

Transmembrane Currents

1. In vivo experiments have shown that extracellular microelectrophoretic application of N-methyl-D-aspartate (NMDA) induced oscillatory plateau potentials with bursts of action potentials in rat abducens motoneurons. The period of these slow NMDA oscillations could be altered by single trigeminal non-NMDA excitatory input delivered at low frequency during the NMDA oscillations. 2. A resetting of the oscillations was observed depending on the phase of slow oscillatory cycle during which the trigeminal excitation occurred. 3. We investigated local mechanisms responsible for the phase-dependent modifications of NMDA oscillations, including contributions of voltage and concentration transients, in the mathematical model of the isopotential membrane compartment equipped with voltage-gated Na+, K+, and Ca2+ channels, with Ca2+-dependent K+ channels, and with ligand-gated NMDA and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor channels. The faithful model was constructed with the use of models described earlier, which were modified by increasing time constants of kinetic variables of all voltage-gated conductances and by including coupled dynamics of voltages and ion concentrations. The changes in ion concentrations were produced near the membrane by transmembrane currents and removal mechanisms (pumps, diffusion). 4. This work focuses on local arrangement of voltage- and ligand-gated conductances and on local ion concentration changes in two separate pools: the postsynaptic pool of AMPA receptors and the extrasynaptic pool. In terms of the electrotonic and diffusional length constants, these pools were electrotonically close but diffusionally remote. 5. It was found that the effect of resetting can be produced by a local interaction between plateau and spike-generating conductances and glutamate receptors. 6. In vivo phase-dependent interactions between NMDA oscillations and AMPA synaptic input were reproduced by the local model only when changes in intracellular sodium and extracellular potassium concentrations were taken into account and the mechanisms of ion removal from postsynaptic pools had slower kinetics than the fast pump system operating in the extracellular pool. 7. Postsynaptic changes in ion concentrations of Na+ and K+ in intra- and extracellular layers near the membrane shift of Nernst equilibrium potentials for these ions depending on the phase of activation of synaptic input. Thus Na+ and k+ components of all transmembrane currents involved in the pattern generation are differently affected by synaptic action during the oscillations. We conclude that slow postsynaptic changes in ion concentrations near the membrane play a key role in the resetting of the NMDA oscillations.

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