The generation of condensation nuclei by ionising radiation

Megaw, W.J.; Wiffen, R.D.

doi:10.1007/bf02000635

Cited by 30 publications

(9 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Later the experiment was repeated with radiation from Uranium with the same result and it was concluded that the droplets were formed on ions (Wilson, 1899). With time other experiments have shown similar effects under conditions with extreme gas compositions or ionisation levels (Megaw and Wiffen, 1961;Bricard et al, 1968;Vohra et al, 1984;Rabeony and Mirabel, 1987;Adachi et al, 1992;Kim et al, 1997), and in normal atmospheric conditions . Dickinson (1975) speculated on how ions can influence aerosol nucleation and clouds; later Arnold (1980) suggested that multi ion complexes can serve as condensation nuclei in the stratosphere, and Turco et al (1998) argued that the recombination of ions could nucleate aerosols.…”

Section: Introductionmentioning

confidence: 77%

“…With the advent of particle counters more detailed studies became possible, and the relation between generated particles and radiation doses of alpha rays from 220 Rn, beta rays, and x-rays were reported (Megaw and Wiffen, 1961) using a Pollak condensation nucleus counter (Metnieks and Pollak, 1959). The doses used were from ∼1 to 15 rads forming ion concentrations orders of magnitude above atmospheric levels, and using this span of doses the particle production rate was increased by more than a factor of 100.…”

Section: Bulk Nucleationmentioning

confidence: 99%

See 1 more Smart Citation

The role of atmospheric ions in aerosol nucleation – a review

2008

View full text Add to dashboard Cite

Abstract. Atmospheric aerosols affect climate and yet the reason for many observed events of new aerosol formation is not understood. One of the theories put forward to explain these events is that the presence of ions can enhance the formation of aerosols. The theory is called Ion Induced Nucleation and in this paper the state of observations, theory and experiments within the field will be reviewed. While evidence for Ion Induced Nucleation is accumulating the exact mechanism is still not known and more research is required to understand and quantify the effect.

show abstract

Section: Introductionmentioning

confidence: 77%

Section: Bulk Nucleationmentioning

confidence: 99%

The role of atmospheric ions in aerosol nucleation – a review

2008

View full text Add to dashboard Cite

show abstract

“…The impact of ionizing radiation on particle formation was first studied in the late nineteenth century by Wilson, who irradiated an expansion chamber with X-rays and radioactive materials, e.g., uranium, and observed that the ions induced droplet formation [Wilson, 1895[Wilson, , 1899. Later experiments [Metnieks and Pollak, 1959;Megaw and Wiffen, 1961] explored the link between the strength of radiation and the concentrations of the resulting particles. Vohra et al [1984] observed enhanced particulate sulfate production when radon was injected into a mixture of SO 2 , O 2 , and C 2 H 4 .…”

Section: Brief Review Of the Effect Of Ions On Particle Formation Stumentioning

confidence: 99%

Effect of ions on sulfuric acid‐water binary particle formation: 2. Experimental data and comparison with QC‐normalized classical nucleation theory

et al. 2016

View full text Add to dashboard Cite

We report comprehensive, demonstrably contaminant‐free measurements of binary particle formation rates by sulfuric acid and water for neutral and ion‐induced pathways conducted in the European Organization for Nuclear Research Cosmics Leaving Outdoor Droplets chamber. The recently developed Atmospheric Pressure interface‐time of flight‐mass spectrometer was used to detect contaminants in charged clusters and to identify runs free of any contaminants. Four parameters were varied to cover ambient conditions: sulfuric acid concentration (105 to 109 mol cm−3), relative humidity (11% to 58%), temperature (207 K to 299 K), and total ion concentration (0 to 6800 ions cm−3). Formation rates were directly measured with novel instruments at sizes close to the critical cluster size (mobility size of 1.3 nm to 3.2 nm). We compare our results with predictions from Classical Nucleation Theory normalized by Quantum Chemical calculation (QC‐normalized CNT), which is described in a companion paper. The formation rates predicted by the QC‐normalized CNT were extended from critical cluster sizes to measured sizes using the UHMA2 sectional particle microphysics model. Our results show, for the first time, good agreement between predicted and measured particle formation rates for the binary (neutral and ion‐induced) sulfuric acid‐water system. Formation rates increase with RH, sulfuric acid, and ion concentrations and decrease with temperature at fixed RH and sulfuric acid concentration. Under atmospheric conditions, neutral particle formation dominates at low temperatures, while ion‐induced particle formation dominates at higher temperatures. The good agreement between the theory and our comprehensive data set gives confidence in using the QC‐normalized CNT as a powerful tool to study neutral and ion‐induced binary particle formation in atmospheric modeling.

show abstract

“…Coagulation rates [ Fuchs , 1964] and aerosol removal rates by droplets (scavenging) [ Pruppacher and Klett , 1997] can be greatly affected by electrical charging of aerosols, which can be further enhanced if the particles are radioactive [ Clement et al ., 1995; Tripathi and Harrison , 2001]. High levels of radioactive ionization [ Bricard et al ., 1968, 1972; Megaw and Wiffen , 1961] can produce ultrafine aerosol particles in artificial and filtered air, and particle formation has also been reported [ Vohra et al ., 1984] at atmospheric levels of radioactivity. Although radiolytically produced ultrafine aerosol particles produced by ionization would have to persist and grow substantially to permit water condensation at atmospheric supersaturations, it is not justified to completely neglect possible direct or indirect electrical influences on aerosols and clouds [ Harrison , 1997, 2000].…”

Section: Introductionmentioning

confidence: 99%

Ion‐aerosol‐cloud processes in the lower atmosphere

Harrison

Carslaw

2003

Reviews of Geophysics

337

328

View full text Add to dashboard Cite

[1] Natural terrestrial radioactivity and cosmic ray ionization lead to the formation of air ions and charged aerosol particles even away from regions of active charge separation, such as in thunderstorms. The natural electrified state of the atmosphere has been studied for over a century; however, the effect of ionization on the physical properties of aerosols and clouds has rarely been studied in its own right except in thunderstorms. Here we review the status of our understanding of atmospheric charged particles and their influence on aerosol and cloud microphysical processes. We also review mechanisms that have been recently proposed to connect variations in the atmospheric ionization rate with variations in global cloudiness and weather systems. We conclude that a mechanism linking cosmic ray ionization and cloud properties cannot be excluded and that there are established electrical effects on aerosol and cloud microphysics. Necessary further work includes measurements of cloud, droplet, and aerosol charging and ion-aerosol conversion, together with modeling of the electrical aspects of nonthunderstorm cloud microphysics.

show abstract

The generation of condensation nuclei by ionising radiation

Cited by 30 publications

References 8 publications

The role of atmospheric ions in aerosol nucleation – a review

The role of atmospheric ions in aerosol nucleation – a review

Effect of ions on sulfuric acid‐water binary particle formation: 2. Experimental data and comparison with QC‐normalized classical nucleation theory

Ion‐aerosol‐cloud processes in the lower atmosphere

Contact Info

Product

Resources

About