See also: Dealing with Breathing Problems written for patients. The term hyperventilation describes excessive ventilation of the lungs, beyond what is required to achieve normal arterial blood gases.
A light frost occurs when the temperature drops to below 32 degrees Fahrenheit, and refers to the conditions that allow a layer of ice crystals to form when water vapor condenses and freezes without first becoming dew. Harvest basil and other tender herbs before a light frost (when the temperature drops to 32 degrees Fahrenheit). 2  Even if they survive the frost, they don't do well in cold temperatures. 3  The same is true for most annuals.
Air frost. An air frost occurs when the air temperature falls to or below the freezing point of water. An air frost is usually defined as the air temperature being below freezing point of water at a height of at least one metre above the ground. Hoar frost.