Voltage dependence of spark resistance at low voltage ESD in air and reed switch

The equivalent circuit of CDM (Charged Device Model) discharge is given by the serial connection of Capacitance (C), Resistance (R) and Inductance (L), then discharge current is calculated by the well known equation. I measured the discharge current waveform of air discharge, dry reed switch discharge and mercury reed switch then compared them against the calculated waveform to estimate the spark resistance dependence upon the discharge vdtage under +/-40V.