sidewalk bomb sniffers in Cleveland?

On various street corners in downtown Cleveland you will find these suitcase sized sniffers...plugged into the traffic light control box electric power or another power source.    5 foot high "chimney" pipes extend up from one end of the unit.  Do these units provide realtime data via cell phone or the internet?    Could we map the movement of a volatile chemical through downtown?   How much do they cost?   Who is paying?   Who built them?

Perhaps a public records request will be made to obtain the air quality data for Downtown Cleveland which these devices  collect during the RNC convention next week.