AirTag is always transmitting 2.45 GHz RF, Bluetooth Low Energy (BLE) signals, roughly every 2 seconds, 24×7.
Even though their signal is very low power (around 0.01–0.1 mW), it’s ALWAYS ACTIVE.
That means it’s radiating continuously, just in short, rapid bursts, millions of times a day.
Low power doesn’t mean “low biological impact” when the signal never sleeps.