A
line source, as opposed to a
point source,
area source, or
volume source, is a source of air, noise, water contamination or electromagnetic radiation that emanates from a linear (one-dimensional) geometry. The most prominent linear sources are
roadway air pollution,
aircraft air
emissions,
roadway noise, certain types of water pollution sources that emanate over a range of river extent rather than from a discrete point, elongated light tubes, certain dose models in
medical physics and electromagnetic
antennas. While
point sources of
pollution were studied since the late nineteenth century, linear sources did not receive much attention from scientists until the late 1960s, when environmental regulations for
highways and
airports began to emerge. At the same time, computers with the processing power to accommodate the data processing needs of the
computer models required to tackle these one-dimensional sources became more available.