{"thcode":2,"term":{"code":6,"name":"acid deposition","parent":66,"scope":"The process by which emissions, chiefly sulfur and nitrogen compounds, either react with the atmosphere when deposited on earth by precipitation of snow, rain, or fog with a pH of 5.5 or below, or settle out as acidic particles or gases."},"uf":[{"name":"acid precipitation","usewith":false},{"name":"acid rain","usewith":false},{"name":"acid snow","usewith":false},{"name":"acidic deposition","usewith":false}],"bt":[{"code":66,"name":"atmospheric deposition (chemical & particulate)","parent":63,"scope":"The transfer of substances from the air to the surface of the earth, either in wet form (rain, fog, snow, dew, frost, hail) or in dry form (gases, aerosols, particles)."},{"code":63,"name":"atmospheric and climatic processes","parent":101,"scope":"Phenomena affecting or occurring within the mass of gases that surrounds the earth, including its physics, chemistry, dynamics, and weather conditions."},{"code":101,"name":"biological and physical processes","parent":1174,"scope":"All continuing activities, functions, and phenomena associated with organisms and non-living matter."},{"code":1174,"name":"topics","parent":1,"scope":"Themes, subjects, and concerns for which USGS information resources are relevant."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":68,"name":"atmospheric sciences","parent":291,"scope":"Studies relating to composition, structure, physics, chemistry, and dynamics of the atmosphere."},{"code":548,"name":"human impacts","parent":1174,"scope":"The effects, intentional or unintentional, beneficial or harmful, direct or indirect, which human activities have upon the environment and living things."}]}