Ozone as concentrations in μg/m. The study of ozone concentration in the atmosphere started in the 1920s. The highest levels of ozone in the atmosphere are in the stratosphere, in a region also known as the ozone layer between about 10 km and 50 km above the surface (or between about 6 and 31 miles). However, even in this "layer", the ozone concentrations are only two to eight parts per million, so most of the oxygen there is dioxygen, O, at about 210,000 parts per million by volume. Ozone in the stratosphere is mostly produced from short-wave ultraviolet rays between 240
The Layer Quaternity The Layer Quaternity The Layer Quaternity are four marble sculpture figurines approximately in height located on the two columns of the Layer Monument, an early 17th-century polychrome mural monument () which was installed in the Church of Saint John the Baptist, Maddermarket, Norwich to the memory of Christopher Layer (1531–1600). The quartet of figurines sculptured in marble, "Pax, Gloria, Vanity, Labor" exhibit primary thematic concerns and stylistic attributes of Northern Mannerist art, namely, portraiture of animated human movement, variety and multiplicity, often set in the Classical or mythological world, and inclined towards esoteric concepts. The Layer Quaternity ("circa" 1598–1604) share