Refrigeration and Air Conditioning
The ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure, is called

Degree of saturation
Relative humidity
Absolute humidity
Humidity ratio

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Refrigeration and Air Conditioning
Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since

These react with ozone layer
These react with plants and cause greenhouse effect
These react with water vapour and cause acid rain
These react with oxygen and cause its depletion

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