A polycyclic aromatic hydrocarbon is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter—by e
Three representations of hexabenzocoronene, a polycyclic aromatic hydrocarbon. Top: standard line-angle schematic, where carbon atoms are represented by the vertices of the hexagons and hydrogen atoms are inferred. Middle: ball-and-stick model showing all carbon and hydrogen atoms. Bottom: atomic force microscopy image.
A wood-burning open-air cooking stove. Smoke from solid fuels like wood is a large source of PAHs globally.
Smog in Cairo. Particulate air pollution, including smog, is a substantial cause of human exposure to PAHs.
Crude oil on a beach after a 2007 oil spill in Korea.
Cosmic dust
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Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. Most cosmic dust particles measure between a few molecules and
Porous chondrite dust particle
Artist's impression of dust formation around a supernova explosion.
Zodiacal light caused by cosmic dust.
Cosmic dust of the Andromeda Galaxy as revealed in infrared light by the Spitzer Space Telescope.