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

2008 ◽  
Vol 8 (3) ◽  
pp. 655-675 ◽  
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.

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

2007 ◽  
Vol 7 (4) ◽  
pp. 9465-9517 ◽  
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%.

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

2005 ◽  
Vol 5 (3) ◽  
pp. 2749-2790 ◽  
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%.

scholarly journals Identification and classification of the formation of intermediate ions measured in boreal forest

2007 ◽  
Vol 7 (1) ◽  
pp. 201-210 ◽  
Author(s):  
A. Hirsikko ◽  
T. Bergman ◽  
L. Laakso ◽  
M. Dal Maso ◽  
I. Riipinen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Aerosol Particle ◽  
Size Range ◽  
Aerosol Particles ◽  
Charged Particles ◽  
Negative Ions ◽  
Particle Formation ◽  
Air Ions ◽  
Charged Aerosol ◽  
Positively Charged

Abstract. We have measured the size distributions of air ions (0.42–7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range covers the size range of cluster ions (approximately 0.42–1.6 nm) and naturally charged nanometre aerosol particles (1.6–7.5 nm) or intermediate air ions. Based on the measurements from April 2003 to March 2006 we studied the characteristics of charged aerosol particle formation by classifying each day either as a particle formation event, undefined or non-event day. The principal of the classification, as well as the statistical description of the charged aerosol particle formation events are given. We found in total 270 (26% of the analysed days) and 226 (22% of the analysed days) particle formation days for negative and positive intermediate ions, respectively. For negatively charged particles we classified 411 (40% of the analysed days) undefined and 348 (34% of the analysed days) non-event days whereas for positively charged particles 343 (33% of the analysed days) undefined and 460 (45% of the analysed days) non-event days. The results were compared with the ordinary classification based on the Differential Mobility Particle Sizer (DMPS) measurements carried out at the same place. The above-presented values differed slightly from that found from the DMPS data, with a lower particle diameter of 3 nm. In addition, we have found the rain-induced intermediate ion bursts frequently. The rain effect was detected on 163 days by means of negative ions and on 105 days by positive ones. Another interesting phenomenon among the charged aerosol particles was the appearance and existence of intermediate ions during the snowfall. We observed this phenomenon 24 times with negatively charged particles and 21 times with positively charged ones during winter months (October–April). These intermediate air ions were seen during the snowfall and may be caused by ice crystals, although the origin of these intermediate ions is unclear at the moment.

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

2016 ◽  
Vol 16 (22) ◽  
pp. 14297-14315 ◽  
Author(s):  
Xuemeng Chen ◽  
Veli-Matti Kerminen ◽  
Jussi Paatero ◽  
Pauli Paasonen ◽  
Hanna E. Manninen ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Boreal Forest ◽  
Ionising Radiation ◽  
Ion Concentration ◽  
Lower Atmosphere ◽  
Air Ions ◽  
Long Distance ◽  
Ion Concentrations ◽  
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. 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.

scholarly journals Identification and classification of the formation of intermediate ions measured in boreal forest

2006 ◽  
Vol 6 (5) ◽  
pp. 9187-9212
Author(s):  
A. Hirsikko ◽  
T. Bergman ◽  
L. Laakso ◽  
M. Dal Maso ◽  
I. Riipinen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Aerosol Particle ◽  
Size Range ◽  
Aerosol Particles ◽  
Charged Particles ◽  
Negative Ions ◽  
Particle Formation ◽  
Air Ions ◽  
Charged Aerosol ◽  
Positively Charged

Abstract. We have measured the size distributions of air ions (0.42–7.5 nm in diameter) with the Balanced Scanning Mobility Analyzer in boreal forest, in Southern Finland since spring 2003. The size range covers the size range of cluster ions (approximately 0.42–1.6 nm) and naturally charged nanometre aerosol particles (1.6–7.5 nm) or intermediate air ions. Based on the measurements from April 2003 to March 2006 we studied the characteristics of charged aerosol particle formation by classifying each day either as a particle formation event, undefined or non-event day. The principal of the classification, as well as the statistical description of the charged aerosol particle formation events are given. We found in total 269 and 226 particle formation days for negative and positive intermediate ions, respectively. For negatively charged particles we classified 411 undefined and 349 non-event days whereas for positively charged particles 342 undefined and 461 non-event days. The results were compared with the ordinary classification based on Differential Mobility Particle Sizer (DMPS) measurements carried out at the same place. The above-presented values differed slightly from that found from the DMPS data, with a lower particle diameter of 3 nm. In addition, we have found the rain-induced intermediate ion bursts frequently. The rain effect was detected on 163 days by means of negative ions and on 104 days by positive ones. Another interesting phenomenon among the charged aerosol particles was the appearance and existence of intermediate ions during the snowfall. We observed this phenomenon 24 times with negatively charged particles and 21 times with positively charged ones during winter months (October–April). These intermediate air ions were seen during the snowfall and may be caused by ice crystals, although the origin of these intermediate ions is unclear at the moment.

scholarly journals Long-term observations of positive cluster ion concentration, sources and sinks at the high altitude site of the Puy de Dôme

2013 ◽  
Vol 13 (6) ◽  
pp. 14927-14975 ◽  
Author(s):  
C. Rose ◽  
J. Boulon ◽  
M. Hervo ◽  
H. Holmgren ◽  
E. Asmi ◽  
...  
Keyword(s):  
Steady State ◽  
High Altitude ◽  
Balance Equation ◽  
Ionization Rate ◽  
Particle Formation ◽  
Ion Concentration ◽  
Cluster Ions ◽  
New Particle Formation ◽  
Cluster Ion ◽  
Ionization Rates

Abstract. Cluster particles (0.8–1.9 nm) are key entities involved in nucleation and new particle formation processes in the atmosphere. Cluster ions were characterized in clear sky conditions at the Puy de Dôme station (1465 m a.s.l). The studied dataset spread over five years (February 2007–February 2012), which provided a unique chance to catch seasonal variations of cluster ion properties at high altitude. Statistical values of the cluster ion concentration and diameter are reported for both positive and negative polarities. Cluster ions were found to be ubiquitous at the Puy de Dôme and displayed an annual variation with lower concentrations in spring. Positive cluster ions were less numerous than negative ones but were larger in diameters. Negative cluster ion properties seemed insensitive to the occurrence of a new particle formation (NPF) event while positive cluster ions appeared to be significantly more numerous and larger on event days. The parameters of the balance equation for the positive cluster concentration are reported, separately for the different seasons and for the NPF event days and non-event days. The steady state assumption suggests that the ionization rate is balanced with two sinks which are the ion recombination and the attachment on aerosol particles, referred as "aerosol ion sink". The aerosol ion sink was found to be higher during the warm season and dominated the loss of ions. The positive ionization rates derived from the balance equation were well correlated with the ionization rates obtained from radon measurement, and they were on average higher in summer and fall compared to winter and spring. Neither the aerosol ion sink nor the ionization rate were found to be significantly different on event days compared to non-event days, and thus they were not able to explain the different positive cluster concentrations between event and non-event days. Hence, the excess of positive small ions on event days may derive from an additional source of ions coupled with the fact that the steady state was not verified on event days.

scholarly journals Measurements of sub-3 nm particles using a particle size magnifier in different environments: from clean mountain top to polluted megacities

2017 ◽  
Vol 17 (3) ◽  
pp. 2163-2187 ◽  
Author(s):  
Jenni Kontkanen ◽  
Katrianne Lehtipalo ◽  
Lauri Ahonen ◽  
Juha Kangasluoma ◽  
Hanna E. Manninen ◽  
...  
Keyword(s):  
Particle Size ◽  
Boreal Forest ◽  
Aerosol Particles ◽  
Anthropogenic Influence ◽  
Subsequent Growth ◽  
Ion Concentrations ◽  
Neutral Particles ◽  
The World ◽  
Different Sources ◽  
Measured Particle

Abstract. The measurement of sub-3 nm aerosol particles is technically challenging. Therefore, there is a lack of knowledge about the concentrations of atmospheric sub-3 nm particles and their variation in different environments. In this study, the concentrations of ∼ 1–3 nm particles measured with a particle size magnifier (PSM) were investigated at nine sites around the world. Sub-3 nm particle concentrations were highest at the sites with strong anthropogenic influence. In boreal forest, measured particle concentrations were clearly higher in summer than in winter, suggesting the importance of biogenic precursor vapors in this environment. At all sites, sub-3 nm particle concentrations had daytime maxima, which are likely linked to the photochemical production of precursor vapors and the emissions of precursor vapors or particles from different sources. When comparing ion concentrations to the total sub-3 nm particle concentrations, electrically neutral particles were observed to dominate in polluted environments and in boreal forest during spring and summer. Generally, the concentrations of sub-3 nm particles seem to be determined by the availability of precursor vapors rather than the level of the sink caused by preexisting aerosol particles. The results also indicate that the formation of the smallest particles and their subsequent growth to larger sizes are two separate processes, and therefore studying the concentration of sub-3 nm particles separately in different size ranges is essential.

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

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

&lt;p&gt;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 &amp;#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 &amp;#8211; 7 nm) can be typically observed during atmospheric new particle formation (NPF) and in precipitation episodes &lt;sup&gt;1&lt;/sup&gt;. Contrary to the intermediate ions formed during NPF that favour growth to larger sizes, intermediate ion bursts resulting from precipitation tend to shrink &lt;sup&gt;2,3&lt;/sup&gt;. The production of intermediate ions during precipitation has been attributed to the Lenard effect and they are usually referred to as the balloelectric ions &lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&lt;p&gt;During precipitation the rain-out and wash-out of radon progeny increase the gamma dose at ground level &lt;sup&gt;4&lt;/sup&gt;. 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&amp;#228;l&amp;#228;, Finland &lt;sup&gt;5&lt;/sup&gt;, 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&amp;#228;, Estonia &lt;sup&gt;6&lt;/sup&gt;. The data collected at Hyyti&amp;#228;l&amp;#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&amp;#228; data for a comprehensive understanding of the observations.&lt;/p&gt;&lt;p&gt;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.&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;1. Tammet, H., Komsaare, K. &amp; H&amp;#245;rrak, U. Intermediate ions in the atmosphere. Atmospheric Research &lt;strong&gt;135-136&lt;/strong&gt;, 263-273, doi:10.1016/j.atmosres.2012.09.009 (2014).&lt;/p&gt;&lt;p&gt;2. H&amp;#245;rrak, U. et al. Formation of Charged Nanometer Aerosol Particles Associated with Rainfall: Atmospheric Measurements and Lab Experiment. Report Series in Aerosol Science &lt;strong&gt;80&lt;/strong&gt;, 180-185 (2006).&lt;/p&gt;&lt;p&gt;3. Tammet, H., H&amp;#245;rrak, U. &amp; Kulmala, M. Negatively charged nanoparticles produced by splashing of water. Atmos. Chem. Phys. &lt;strong&gt;9&lt;/strong&gt;, 357&amp;#8211;367 (2009).&lt;/p&gt;&lt;p&gt;4. Paatero, J. &amp; Hatakka, J. Wet deposition efficiency of short-lived radon-222 progeny in central Finland. Boreal Env. Res. &lt;strong&gt;4&lt;/strong&gt;, 285-293 (1999).&lt;/p&gt;&lt;p&gt;5. Hari, P. &amp; Kulmala, M. Station for measuring ecosystem-atmosphere relations (SMEAR II). Boreal Environ. Res. &lt;strong&gt;10&lt;/strong&gt;, 315-322 (2005).&lt;/p&gt;&lt;p&gt;6. Noe, S. M. et al. SMEAR Estonia: Perspectives of a large-scale forest ecosystem &amp;#8211; atmosphere research infrastructure. Forestry Studies &lt;strong&gt;63&lt;/strong&gt;, doi:10.1515/fsmu-2015-0009 (2015).&lt;/p&gt;

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

1988 ◽  
Vol 66 (12) ◽  
pp. 2445-2451 ◽  
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.

scholarly journals Effect of Environmental Factors on Air Ion Concentration

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

<p class="R-AbstractKeywords"><span lang="EN-US">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, NO<sub>2</sub>, NO<sub>x</sub>, SO<sub>2</sub>, O<sub>3</sub>, 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.</span></p>

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