Michigan EGLE’s (Environmental, Great Lakes and Energy) Air Quality Division has various types of equipment to help monitor and measure emissions of some pollutants. One of these devices is called a SEM 5000 and it is used to measure levels of methane. This device can take readings really quickly and gives inspectors a way to potentially identify problems which may be hard to detect. These measurements are taken primarily at landfills, but can be used at any industry where emissions of methane may need to be looked at more closely.
See the YouTube video which describes the process: https://www.youtube.com/watch?v=Vm2UpPwrR3I