In May of 2021 the FCC adopted guidelines and procedures for evaluating environmental effects of RF emissions. The guidelines incorporate two tiers of exposure limits based on whether exposure occurs in an occupational or “controlled” situation, or whether the general population is exposed or exposure is in an “uncontrolled” situation. In addition to guidelines for evaluating fixed transmitters, the FCC adopted limits for evaluating exposure from mobile and portable devices, such as cellular telephones and personal communications devices.
From the ARRL:
“Amateur Radio is basically a safe activity. In recent years, however, there has been considerable discussion and concern about the possible hazards of electromagnetic radiation, including both RF energy and power-frequency (50-60 Hz) electromagnetic fields. To allay such concerns, the FCC set limits on the amount of RF energy people can be exposed to. Some stations need to be evaluated to see if they are in compliance with the rules. (You don’t need to send anything to the FCC once you complete your evaluation.)
If you do a station evaluation for one or more powers or modes, you can use the ARRL worksheet to guide you through the process. This single page worksheet and instructions will suffice for many stations. You can keep this worksheet in your station records,
You can also use the online calculator:
http://arrl.org/rf-exposure-calculator Fill-in the form with your operating power, antenna gain, and the operating frequency. “Depending on how far above ground the RF source is located, you might want to consider ground reflections — and then click ‘Calculate’. You may need to run the calculator multiple times to get a complete picture of your situation, i.e. take into account the antenna’s lobes and directionality.” (These suggestions are from the Lake Washington Ham Club.)
See Chapter 5 of the ARRL “RF Exposure and You” book for more information about multiple-transmitter sites. This book may be downloaded, although some of the information on categorical exemptions for amateur radio has been superseded by the new rules changes. The book can be downloaded for free.
See also:
ARRL FAQ page: http://arrl.org/rf-exposure
ARRL Calculator parameters: http://arrl.org/rf-exposure-calc-instructions