Dust measurement can take several different forms. One of these is the internationally recognised Bergerhoff Method. This is where a Bergerhoff Dust gauge which complies with Bergerhoff 12345 measurement is placed in an appropriate location for a period of 30 days. During this period, any airborne particles are captured in the dust gauge along with any rainwater during the period. After 30 days the container with dust and rainwater is brought back to the lab for solids measurement using gravimetric and evaporation techniques. There is a common recognised standard of 350 mg/m2/day.