Evolution of negative small air ions at two different temperatures

Luts, Aare; Parts, Tiia-Ene

doi:10.1016/s1364-6826(02)00076-7

Cited by 34 publications

(43 citation statements)

References 40 publications

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“…Luts and Parts, 2002;Parts and Luts, 2004). The mean mobility or size of small ions has thus been reported in the literature (see Hirsikko et al, 2010 and references therein).…”

Section: Mean Diameter and Concentration Comparisonmentioning

confidence: 90%

Intercomparison of air ion spectrometers: an evaluation of results in varying conditions

et al. 2011

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Abstract. We evaluated 11 air ion spectrometers from Airel Ltd. after they had spent one year in field measurements as a part of the EUCAARI project: 5 Air Ion Spectrometers (AIS), 5 Neutral cluster and Air Ion Spectrometers (NAIS) and one Airborne NAIS (ANAIS). This is the first time that an ANAIS is evaluated and compared so extensively. The ion spectrometers' mobility and concentration accuracy was evaluated. Their measurements of ambient air were compared between themselves and to reference instruments: a Differential Mobility Particle Sizer (DMPS), a Balanced Scanning Mobility Analyzer (BSMA), and an Ion-DMPS. We report on the simultaneous measurement of a new particle formation (NPF) event by all 11 instruments and the 3 reference instruments. To our knowledge, it is the first time that the size distribution of ions and particles is measured by so many ion spectrometers during a NPF event.The new particle formation rates (∼0.2 cm −3 s −1 for ions and ∼2 cm −3 s −1 for particles) and growth rates (∼25 nm h −1 in the 3-7 nm size range) were calculated for all the instruments. The NAISs and the ANAIS gave higher concentrations and formation rates than the AISs. For example, the AISs agreed with the BSMA within 11 % and 28 % for negative and positive ion concentration respectively, whereas the NAISs agreed within 23 % and 29 %. Finally, based on the results presented here, we give guidelines for data evaluation, when data from different individual ion spectrometers are compared.

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“…Luts and Parts, 2002;Parts and Luts, 2004). The mean mobility or size of small ions has thus been reported in the literature (see Hirsikko et al, 2010 and references therein).…”

Section: Mean Diameter and Concentration Comparisonmentioning

confidence: 90%

Intercomparison of air ion spectrometers: an evaluation of results in varying conditions

et al. 2011

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“…The negative ions have greater affinity for the condensing vapours 31,32 , consequently the ion-mediated particle formation mechanisms are expected to be important in locations with high relative humidity 33,34 , close to 100% (for example, in caves). The small air ions are usually composed of the central primary ion and surrounding 4-10 molecules of water, depending on humidity, temperature, actual concentration of trace gasses 35 and polarity of the ions.…”

Section: Discussionmentioning

confidence: 99%

Subterranean atmospheres may act as daily methane sinks

et al. 2015

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In recent years, methane (CH 4 ) has received increasing scientific attention because it is the most abundant non-CO 2 atmospheric greenhouse gas (GHG) and controls numerous chemical reactions in the troposphere and stratosphere. However, there is much that is unknown about CH 4 sources and sinks and their evolution over time. Here we show that near-surface cavities in the uppermost vadose zone are now actively removing atmospheric CH 4 . Through seasonal geochemical tracing of air in the atmosphere, soil and underground at diverse geographic and climatic locations in Spain, our results show that complete consumption of CH 4 is favoured in the subsurface atmosphere under near vapour-saturation conditions and without significant intervention of methanotrophic bacteria. Overall, our results indicate that subterranean atmospheres may be acting as sinks for atmospheric CH 4 on a daily scale. However, this terrestrial sink has not yet been considered in CH 4 budget balances. M ethane (CH 4 ) is currently the most abundant non-CO 2 greenhouse gas (GHG) in the atmosphere, reaching a global average concentration of B1,800 p.p.b. at midnorthern latitudes 1 . Despite significant research progress in recent years, large uncertainties remain about the CH 4 budget and its evolution over time because there is a lack of knowledge about CH 4 sinks and sources [2][3][4][5] . Superimposed on the long-term trend of increasing atmospheric CH 4 , there is significant interannual variability 1,6,7 , and the sources of variation remain controversial 8 .Current CH 4 estimates account for B22% of the total forcing potential of all long-lived GHGs 9 . By weight, CH 4 is 28 times more effective at trapping heat in the atmosphere than CO 2 over a 100-year period 10 . Sensible mitigation strategies also require a quantitative understanding of the CH 4 budget regarding emissions and sinks 11 . The total global emissions of CH 4 are constrained reasonably well by atmospheric observations and estimates of its lifetime, based on multiple atmospheric CH 4 inversion models (top-down studies). However, the uncertainties concerning emissions/consumption from individual sources/ sinks 12 are greater, and they are poorly constrained by the current atmospheric observation network 6 . Some unaccounted sinks (or sources) could contribute the global CH 4 budget and its long-term variations.The Earth's surface exerts its influence on the free atmosphere through the atmospheric boundary layer. This lowest portion of the atmosphere ranges from a few tens of metres to 1-2-km deep 13 . The subsurface atmosphere is usually overlooked as an important part of this boundary layer. At the top of the subsurface layer in the vadose zone (below the subsoil and above the groundwater table) highly specific biogeochemical processes occur, which may act as regulators of gas exchanges between the surface and the free atmosphere.The uppermost part of the vadose zone may contain large amounts of underground air, that is, a CO 2 -rich air reservoir permeating the unsaturated...

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“…The positive and negative small ions exhibit very different chemical composition (Eisele and Tanner, 1990;Beig and Brasseur, 2000;Luts and Parts, 2002). Typically positive core ions consist of hydronium (H 3 O + ), ammonium (NH + 4 ) and a variety of organic compounds (e.g.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2008

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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 forCorrespondence to: U. Hõrrak (urmas.horrak@ut.ee) est 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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Evolution of negative small air ions at two different temperatures

Cited by 34 publications

References 40 publications

Intercomparison of air ion spectrometers: an evaluation of results in varying conditions

Intercomparison of air ion spectrometers: an evaluation of results in varying conditions

Subterranean atmospheres may act as daily methane sinks

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

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