FFT and PowerSpectrum, question about the dimentional units.

Hello, I am computing the FFT of a signal pressure (wy) expressed with
Pascal dimentional unit according to the matlab formula below. Which
kind of dimentional units should the vector Pyy1 will become? Still
Pascal?

Y1 = fft(wy1,N);
Pyy1 = Y1.* conj(Y1) / N;

Thanks in advance
Nick
.