Measuring Humidity
摘要
Humidity (both absolute and relative) is defined. Methods for measuring humidity are described including the hair hygrometer, wet and dry bulb, condensation methods, methods involving a change in electrical properties, mass spectrometry and alterations in absorption of electromagnetic radiation. The physiological principles which underpin the requirement for humidification of inspired gases are explained. Methods of humidification are described, including heat and moisture exchangers, water baths, circle systems and CO2 absorbers, and nebulisers.