Old English broc garment for the legs and trunk; see breeches). The sense might reflect the breeches sense, on the notion of two limbs or of appliances used in pairs. The typographical bracket is first recorded 1750, so called for its resemblance to double supports in carpentry (a sense attested from 1610s). Senses affected by Latin brachium arm..
Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though living things emit carbon dioxide when they breathe, carbon dioxide is widely considered to be a pollutant when associated with cars, planes, power plants, and other human activities that involve the burning of fossil fuels such as gasoline and natural gas.
Nonpoint source pollution includes many small sources, like septic tanks, cars, trucks, and boats, plus larger sources, such as farms, livestock ranches, and timber harvest areas. Pollution that comes from a single source like an oil or chemical spill is known as point source pollution.Often this type of pollution has large impacts but fortunately they occur less often. Discharge from faulty or damaged factories or water treatments system are also considered point source polluters.ollution that comes from a single source like an oil or chemical spill is known as point source pollution. Often this type of pollution has large impacts but fortunately they occur less often.