This means that during a full on Ghostbusting offensive with entities being wrangled by proton streams and being trapped into traps the whole scene would smell like a thunderstorm.
That sharp smell of ozone, anions and cations before a large thunderstorm arrives. A smell slightly reminiscent of chlorine in a swimming pool.
I never realised that. Think about it the next time you smell that.
It's impressive how thematically Ghostbusters subverts our (very real) fear of the unknown of life after death by utilising the unreduced entirety of that which stands at its polar opposite; science, technology, human engineering achievement, in its unreduced entirety, down to it's frickin' smell.
Even further reading (wikipedia):
Ozone may be formed from O2 by electrical discharges and by action of high energy electromagnetic radiation. Unsuppressed arcing in electrical contacts, motor brushes, or mechanical switches breaks down the chemical bonds of the atmospheric oxygen surrounding the contacts [O2 → 2O]. Free radicals of oxygen in and around the arc recombine to create ozone [O3]. Certain electrical equipment generate significant levels of ozone. This is especially true of devices using high voltages, such as ionic air purifiers, laser printers, photocopiers, tasers and arc welders.
Ions can be non-chemically prepared using various ion sources, usually involving high voltage or temperature. These are used in a multitude of devices such as mass spectrometers, optical emission spectrometers, particle accelerators, ion implanters, and ion engines.