Mitigating methane emissions is an important first step for mitigating anthropogenic global warming. In order to verify emissions reductions, we use various atmospheric measurements order to quantify emissions from various sources. Three measurement techniques are presented. Side-by-side comparisons between different EM27/Sun spectrometers are presented. An instrument-specific Gaussian Plume inversion model is developed for our mobile in situ measurements, and work towards using low-cost metal oxide gas sensors for measuring methane is discussed.