condensation nucleus A small particle of an atmospheric impurity (e.g. salt, dust, or smoke), which provides surfaces for the condensation of water. Condensation nuclei vary in size from about 0.1 μm to more than 3 μm. Some nuclei (e.g. salt and acid particles) can encourage condensation at a relative humidity well below 100 per cent. See also Aitken nucleus; condensation level; and hygroscopic nucleus.

condensation nucleus Small particle of an atmospheric impurity (e.g. salt, dust, or smoke), which provides surfaces for the condensation of water. Condensation nuclei vary in size from about 0.1 μm to more than 3 μm. Some nuclei, e.g. salt and acid particles, can encourage condensation at a relative humidity well below 100%. See also AITKEN NUCLEUS; and HYGROSCOPIC NUCLEI.