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Surface Emissions Monitoring (SEM)

Surface emissions monitoring (SEM) describes a method for measuring gas emissions at or near ground surfaces.  The term is most commonly referred to the method of detecting methane emissions over the surface of a landfill, but can also apply to monitoring methane emitted from buried natural gas pipelines, measuring methane emissions over covered lagoons and open bodies of water such as tailing ponds, measuring nitrous oxide emissions in agriculture applications, and others.


Generally, work is performed manually by technicians while traversing the study area utilizing a hand-held closed-path detector with an air collection nozzle. Ambient air samples are collected though the nozzle at the ground surface and pumped to the detector where concentrations of the subject gas is measured. 

Method 21 Surface Emissions Monitoring

The purpose of the work is to collect raw data of gas concentrations and/or to detect and isolate leak sources of the subject gas.  


Sniffer has developed the SnifferDRONE™ -  a unmanned aerial system (UAS) designed as an automation tool automating much of the work performed manually by field technicians. This technology now offers industry an alternative to an otherwise hazardous, laborious, and subjective method, by providing a safer, faster, and more effective solution.  Learn more.

Explore the use cases below to learn more about the applications for surface emissions monitoring.

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