Estimation of small ion concentration near the Earth's surface

Abstract

a b s t r a c tAtmospheric ions produced by radon gas exhalation from the Earth's surface can play a vital role in the electrification of atmosphere, especially during nights when the gases are trapped in a stable layer close to the surface. The measurements of concentration of radon and its progeny, air conductivity and aerosol size distribution made at Pune, India, have been analyzed. The concentrations of radon and its progeny show maxima during night and early morning hours, between 0500 and 0700 IST when atmosphere is more stable and mixing is low and start decreasing after sunrise and attain minima during 1000-1800 h when air is unstable. The diurnal variation of the ionization rate, calculated using the concentrations of radon and its progeny, follows the variations of concentrations of radon and its progeny. The ion-aerosol balance equations are solved to study the effect of aerosols on small ion concentration in the lower atmosphere. It has been found that during daytime when aerosol concentration is high, 20-30% reduction in small ion concentration can occur due to aerosols. The small ion concentration estimated using measured air conductivity is compared with small ion concentration estimated by solving ion-aerosol balance equations and both are found to be in good agreement with each other.

Atmospheric ions and new particle formation events at a tropical location, Pune, India

“…PECIA could not be associated with local traffic as the periods and timings of ion/aerosol particle concentration maxima generally preceded by 2–3 h the peak traffic hours, which were ∼0900–1100 LT at this location. Earlier observations of enhancement of ions and conductivity (Dhanorkar and Kamra, ) and radon concentrations (Kamsali et al , ) observed at the Atmospheric Electricity Observatory,∼100 m away from this site, were also reported during the same period. Such enhancements of ions and aerosol particles can be associated with accumulations of ions, aerosols, radioactive decay products and precursor gases below inversion layers at night‐time (Porstendörfer, ) and their downward transport with the ketabatic winds along the surrounding hill‐slopes in the morning.…”

“…Observation of a high peak in ionization rate at about 0600 LT in our radon measurements (Figure ) strongly indicates such downward advection of radon along the hill‐slopes at the measuring site. Supporting such a transport are earlier observations of peaks in ion concentration and electrical conductivity (Dhanorkar and Kamra, ) and radon concentration (Kamsali et al , ) in the early morning hours at the Atmospheric Electricity Observatory, located ∼100 m from this site which also reported similar accumulations of ions and radon and were explained by a similar transport mechanism.…”

“…The values of ionization rate shown in Figure are thus less by this amount. Earlier measurements conducted close to this site also produced comparative values (Kamsali et al , ).…”

Indoor and outdoor atmospheric ion mobility spectra, diurnal variation, and relationship with meteorological parameters

“…Outdoors, radon will accumulate more in stable atmospheric conditions, so one might expect higher concentrations overnight, when stability is generally higher, with a corresponding increase in ionization, and a decrease after sunrise, as observed by Kamsali et al . []. This also explains the inverse relationship between wind speed and ion concentration, as greater mixing within the boundary layer lowers outdoor radon concentration and ionization rate.…”

Electrical Conductivity of the Stratosphere

“…The ion-aerosol model used in this study is shown in Fig. 1, whereas the details of this model for surface level conductivity near to the earth's surface under enhanced aerosol conditions is described by Nagaraja et al [6] and variation of small ions by Nagaraja et al [7]. The two types of  for the attachment of positive and negative ions with the neutral aerosols are considered to be equal.…”