Habitat: place where a population (e.g. human, animal, plant, micro-organism) lives and its surroundings, both living and non-living. habitat, siedlisko

Haddon matrix: nine-cell matrix used by public health workers to determine where best to apply strategies to prevent or control injuries; accidents are divided into three phases: preevent phase (factors that determine whether an accident occurs) the event itself, and the post-event phase (everything that determines the consequences of the injuries received). Factors operating in all three phases are the humans involved, the equipment they are using or with which they come in contact, and the environment in which the equipment is operated. macierz Haddona

Haemorrhage (hemorrhage): massive bleeding or loss of blood. krwotok

Hailstorm: natural disaster where a thunderstorm produces a numerous amount of hailstones that damage the location in which they fall. burza gradowa

Half-life: 1. time required for a pollutant to lose half its effect on the environment, e.g. the biochemical half-life of DDT in the environment is 15 years; okres półtrwania 2. time required for half of the atoms of a radioactive element to undergo self-transmutation or decay; okres połowicznego rozpadu3. time required for the elimination of one half a total dose from the body. półtrwanie

Halogen: one of the chemical elements fluorine, chlorine, bromine, iodine or astatine. halogen, fluorowiec

Handicapped: any person who has a physical or mental impairment or disability that significantly limits ones capacity to function, has a record of such impairment, or is regarded as having such an impairment; cf. physical disadvantage. niepełnosprawny, upośledzony

Hard water: alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from lathering.