What is the effect of humidity on sphere gap?

Humidity affects sphere gaps by influencing the dielectric strength of the air surrounding the spheres. High humidity increases the concentration of water vapor, which can lead to ionization and a decrease in the air's insulating properties, potentially resulting in premature flashover. This can reduce the effective voltage level at which the gap will break down, making it critical to consider environmental conditions when designing systems that utilize sphere gaps for insulation purposes.