The correct relation between the highest rainfall $P_0$, average rainfall depth $P$, and area $A$ (in km\textsuperscript{2}) is:
\[P = P_0 \exp(-K A^n)\]
Here:
$P_0$ is the highest rainfall (in cm),
$P$ is the average rainfall depth (in cm),
$A$ is the area of the region (in km\textsuperscript{2}),
$K$ and $n$ are storm constants that depend on the characteristics of the storm.
Final Answer: $P = P_0 \exp(-K A^n)$ (Option 1)
A particle dispersoid has 1510 spherical particles of uniform density. An air purifier is proposed to be used to remove these particles. The diameter-specific number of particles in the dispersoid, along with the number removal efficiency of the proposed purifier is shown in the following table:
The overall mass removal efficiency of the proposed purifier is ________% (rounded off to one decimal place).