In some juristictions it is possible to monitor and decode Fire & EMS pager traffic.
Hospital pagers are also quite common to see.

This video demonstrates how to set up a simple pager decoding systems using a basic Software Defined Radio (SDR) and some free software.

Please check the legality of decoding pager traffic in your region before doing this.

I used SDR++ and PDW to perform the decodes in this video.
I also used an old generic SDR, but I highly recommend using either an RTL-SDR v3 or a NooElec SMArt as these devices are more stable, and you’ll not suffer from any frequency drift. These devices will increase your chances of maintaining a successful decode rate.