Minimum charge needed for spark between two point charges 1m apart in air?

Hello everyone,

I've been looking on the web for an answer to this question for while, but couldn't find a proper answer yet, hope you guys can help.

If I had two point charges, holding charges X and Y, the space between the 2 point charges is 1 Meter, and they were spaced by air between them.
What is the minimum amount of charge that these 2 point charges has to hold in order to have a spark between them? is there a rule that govern such a case?

Note: I saw online that the breakdown value for air is 30KV / cm, but i couldn't translate this into a charge (in coloumbs).

Also, i don't care what is the difference in charge between X and Y....


Thanks,