Here is a
link to a page that contains a calculator for this. it appears to be reasonably accurate although each installation will be different and can have peaks and nodes in the RF field intensity.
Distance is your friend in terms of compliance and safety all other things being equal (power and frequency of operation).
Enter the information called for and it will do the work for you. It will indicate if your operation is in compliance with the FCC established RF exposure limits.
Note the difference in average power levels for different modes of operation.
For those in your apartment complex that might question your operation, this is at least one piece of evidence to show that you are in compliance with the FCC exposure limits, if you are.
That said, it is not a bad idea to limit ones exposure to RF to the minimum practicable for the task at hand for safety and to limit possible unwanted RFI to others.