I worked on a project called Bikenet at Dartmouth College that used bicycles for sensing carbon dioxide: https://www.cs.dartmouth.edu/~sensorlab/pubs/BikeNet-S

I worked on a project called Bikenet at Dartmouth College that used bicycles for sensing carbon dioxide: https://www.cs.dartmouth.edu/~sensorlab/pubs/BikeNet-SenSys07.pdf https://www.cs.dartmouth.edu/~sensorlab/pubs/BikeNet-SenSys0... http://sensorlab.cs.dartmouth.edu/pubs/a6-eisenman.pdf http://sensorlab.cs.dartmouth.edu/pubs/a6-eisenman.pdf We tried measuring carbon monoxide also but CO is lighter than air so we got no measurements. Methane is also lighter than air and would probably not be measurable on the ground unless you were very close to the source. However, the biker could carry a drone with a methane sensor and launch it periodically: https://www.ravanair.com/drone-uav-methane-gas-detection/ https://www.ravanair.com/drone-uav-methane-gas-detection/ Maybe a laser could be mounted on the bike firing straight up and be used to detect methane?: https://www.crowcon.com/products/portables/lmm-gen-2/ https://www.crowcon.com/products/portables/lmm-gen-2/ I wanted to add radiation sensors to the bikes but the prof vetoed that idea, afraid it might affect property values in the town if we actually found differences in radiation levels.