Is There Still Radiation in Hiroshima and Nagasaki?

Current Radiation Levels

Today, the radiation in both Hiroshima and Nagasaki is comparable to the extremely low levels of background radiation that are naturally present everywhere on Earth.
The existing radiation levels have no harmful effects on human health.

Atomic bombs release explosive energy and radiation, different from conventional bombs.
Initial Radiation:
- Accounted for 5% of the bomb's total energy.
- Inflicted severe damage at the moment of detonation, especially within a one-kilometer radius, causing the deaths of most individuals exposed.
Residual Radiation:
- Made up 10% of the bomb’s energy.
- Released post-detonation.
- Approximately 80% of residual radiation was emitted within the first 24 hours.

24 hours after the explosion, residual radiation at the hypocenter reduced to 1/1000th of the initial radiation.
A week later, it further declined to 1/1,000,000th of the initial level.
This rapid decline indicates the short-lived nature of the residual radiation from the bombings.

The radiation levels in Hiroshima and Nagasaki are now safe and pose no threat to human health, akin to natural background radiation levels found globally.