By definition, sure. But one always needs some effect which changes some electrical property. We can't just hook up an ADC (analog digital converter) to thin air and hope for the best.

In practice most microphones measure the displacement of microscopic membranes, which are deformed by the air pressure. The next question then becomes how to measure microscopic movements of a tiny membrane. Turns out the membrane forms part of a capacitor and the electrical characteristics of capacitors depend on their geometry.