The mass difference between humans and viruses is something like 10^19.
So if you take the naive approach -- which is wrong, because charges live on surfaces, not in volumes -- you would want the person to have about a coulumb of charge to ensure that 1 extra electron was allocated to each virus particle.
Whether or not 1 electron per virus is enough is a separate question, but that gives you a lower bound -- if you are allocating, say, 0.1 electrons, only 10% of your virus particles will have a charge.
Edit: so, given the capacitance of humans as 200 pF, that would be 5 gigavolts?
Using the size of aerosolized droplets (0.35-10um) and the mass of human skin (20 lbs) would knock two orders of magnitude off, and drop the floor estimate to 50 megavolts.
For anyone wondering what a 50MV source looks like, one was actually built out in the desert near Joshua Tree in '54. Strangely, it was built for longevity research. Well, that and UFOs and anti-gravity, because of course:
"The Multiple Wave Oscillator is a combination of a high voltage Tesla coil and a split-ring resonator that generates ultra wideband electromagnetic frequencies."
The ionization of the air in the main room was quite intense, with plasma freely forming coronas.
Once the pandemic is over, you can drive out to get a 'sound bath' in the room, if you are so inclined.
Re: capacitance, our capacitance is too low. The higher the capacitance the lower the voltage. A 1 farad capacitor could hold 1 coulomb of charge at 1 volt of potential difference. A 0.1 farad capacitor could hold 0.1 coulomb of charge at 1 volt, or 1 coulomb of charge at 10 volts, or 0.01 coulombs of charge at 0.1 volts, or 100 coulombs of charge at 1000 volts.[0]. Because our capacitance is so low, you need a huge amount of voltage to force all of those electrons onto us.
[0] Assuming the capacitor didn't fail -- in the case of actual capacitors, they only operate within certain parameters and tend to explode outside of them, in the case of people in an atmosphere, you'd probably see those discharges well before you managed to shove a full coulomb of charge onto one.
So if you take the naive approach -- which is wrong, because charges live on surfaces, not in volumes -- you would want the person to have about a coulumb of charge to ensure that 1 extra electron was allocated to each virus particle.
Whether or not 1 electron per virus is enough is a separate question, but that gives you a lower bound -- if you are allocating, say, 0.1 electrons, only 10% of your virus particles will have a charge.
Edit: so, given the capacitance of humans as 200 pF, that would be 5 gigavolts?