Air Pump Motor???

I was looking in the fuse center under the hood and I found a missing relay. I looked on the cover and it said "Air pump motor". The car is a 2000 grand am with a 2.4 engine, Just wanted to know what it is. thanks

Some models of N bodies (V-6) used an electric air pump for secondary air injection on startup to limit CO emissions until the oxygen sensors were actively controlling fuel mixture (in open loop mode). Your Grand Am does not use such a pump with the DOH! cam four-holer, but the same fuse/relay panels were installed in all N bodies, thus the "missing" relay.

thanks alot