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.
Summary. All of these examples illustrate sources of pollution and contamination in the environment. If the origin of the pollution can be traced to a single point, it is called point source pollution.If the pollutants are entering the environment in a widespread fashion, or the pollution is of a general nature and cannot be traced to a single source, it is said to be non-point-source pollution. After individual lists are prepared, the class prepares a list of all of the pollutants and types of pollution that they have identified. 2  The items in the class list are sorted as to whether they are examples of point source pollution or non-point-source pollution.