Gaseous products created by electrical discharges in the atmosphere and condensation nuclei resulting from gaseous phase reactions

Abstract

Our study has a double aim. Firstly, to study the production of NO, NO x, O 3 and condensation nuclei by electrical discharges. Secondly, to attempt to make an estimation of the natural production for the whole earth of these products by atmospheric discharges. We deal firstly with atmospheric electrical discharges which are simulated in a point-to-plane discharge vessel in which we can alter the mean current, the point polarity and the relative humidity (R.H.). We used natural or bottled air or bottled nitrogen with a constant gas flow of 55 f h −1. We noted that the production of O 3 takes place mainly during predischarge regimes, whilst spark discharges are mainly productive of NO and NO x. Condensation nuclei (C.N.) seem to be produced by gaseous phase reactions between NO x and O 3 and depend on R.H. Secondly, we calculate the global production of these species by atmospheric electrical discharges. For the NO x we take account of our experimental results and of the hypothesis used elsewhere by Chameides et al. (1977) and for the O 3 Griffing's hypothesis (1977) as well as thunderstorm statistics given by Schonland (1953). Our estimation for NO x is of 25Tgy −1 and for O 3 our calculations give a lower limit of about 90Tgy −1 which seems to indicate that production of O 3 by atmospheric electrical discharges (corona or point discharges and lightning) is more important than usually assumed. In the actual state of the measurements, it seems unreasonable to attempt to give an estimation of production of the C.N. Complementary experiments with bottled nitrogen seem to indicate that atomic oxygen and OH radicals do not play an initial role in C.N. creation. Our results lead us to believe that these C.N. may be HNO 3 products.