Scuba diver in danger?

A novice scuba diver practicing in a swimming pool takes enough air from his tank to fully expand his lungs before abandoning the tank at depth $L$ and swimming to the surface. He ignores instructions and fails to exhale during his ascent. When he reaches the surface, the difference between the external pressure on him and the air pressure in his lungs is $9.3 \text{ kPa.}$ What is $L?$

The gravitational acceleration is $g= 9.8 \text{ m/s}^{2}$ .
The density of water is $998 \text{ kg/m}^{3}.$