A method for determining the water content of a hygroscopic fluid. The method includes inserting an amount of hygroscopic fluid into a fluid ejection cartridge; attaching the fluid ejection cartridge to a fluid ejection device; activating the fluid ejection cartridge to dispense a predetermined number of fluid droplets from one or more nozzles of an ejection head attached to the fluid ejection cartridge onto a substrate to determine a total mass of the fluid droplets dispensed, a velocity of the dispensed fluid droplets or a combination of the total mass of the fluid droplets dispensed and the velocity of the dispensed fluid droplets; and using an information database that correlates the water content of the hygroscopic fluid to an average mass per fluid droplet dispensed and the velocity of the fluid droplets dispensed to determine the water content of the hygroscopic fluid.

A sensor includes an emitter electrode configured to be disposed at a first position and exposed to a fluid airflow. The emitter electrode is configured to generate charged particles proximate the emitter electrode via a voltage pulse. The sensor includes a collector electrode configured to be disposed at a second position and exposed to the fluid airflow. The second position is aft of the first position. The collector electrode is configured to detect a current associated with a flow of the charged particles during relative movement of the fluid airflow. The sensor includes one or more processors coupled to the emitter electrode and the collector electrode, wherein the one or more processors are configured to measure a duration between the voltage pulse and the current, and wherein the duration is indicative of a speed of a vehicle.