Home Office Ventilation - Suggestions?

[white_s2k]

After 3 long years, I'm in the position to be able to work from home most days starting next week. I have a 12x12 foot room that I am converting into a home office. It has a standard size window, would the best option here just be a standard box fan pushing the air from the room to the outside?

Any suggestions on the best way to pump fresh air/oxygen into the room when I'm done working for the day?

Thanks!