Definition - What does Hygrometer mean?
A hygrometer is an instrument used to measure relative humidity. It is also called a psychrometer. In order to determine relative humidity, the hygrometer makes use of wet and dry bulb thermometers. The difference in temperatures between the two measurements are an indicator of evaporation, therefore also relative humidity. Older hygrometers were used with the aid of a chart, which was used for the interpretation of readings, but digital hygrometers are more commonly used now. In order to maintain workplace air quality, relative humidity should be 20 - 60%.
Safeopedia explains Hygrometer
Health and safety professionals are required to monitor indoor air quality, record the results and make recommendations if air quality falls outside acceptable parameters. The amount of moisture in the air affects respiratory health, as well as physical comfort. The measurement of relative humidity is therefore an important element in the maintenance of indoor air quality. An OSHA approved hygrometer should be used, since the accuracy of commercial hygrometers is variable. Humidity measurements should be recorded together with temperature readings, and workplace ventilation systems should be tested regularly.