Density is a physical property of matter, and by knowing the density of a mixture you can often infer other properties of the mixture. The vibrating element method is one way of measuring the density of a gas that can be used in power, pulp and paper, refining, and chemical industries.
Lighting can be an issue for remote sensor control systems, especially in the upstream oilfield. Sensors located on top of 20 – 24 ft. steel tanks become ideal targets for lightning. One unfortunate strike can take out a sensor or the entire telemetry system.