From the ARRL website http://www.arrl.org/rf-exposure
“The FCC has made changes to the RF-exposure rules that change the ways that radio stations can determine whether they are exempt from the need to do a routine RF-exposure station evaluation. To answer the questions HQ staff are receiving about these changes, ARRL has prepared an RF-exposure FAQ to help hams understand the new rules.”
The website has lots of helpful information and access to an RF exposure calculator that makes most of this simpler.
A presentation on exposure is on the RARC YouTube channel and slides can be found here > RF Exposure program – RARC.