A class of stony meteorites that lack chondrules. They are made of rock that has crystallized from a molten state. Achondrites are relatively rare, accounting for about 8% of all meteorite falls.
Freshwater ice consisting of numerous long crystals and hollow tubes having variable form, layered arrangement, and a content of air bubbles. This ice often forms at the bottom of an ice layer near it
s contact with water.
Occurrence of fog or haze in which considerable amounts of acidic material have been taken up from the gas phase, resulting in pH values less than approximately 3 in the liquid phase.
A popular expression for the deposition by rainfall of various airborne pollutants (especially SO2 and NO2) that have harmful effects on vegetation, soils, buildings and other external structures.