Paul Jozef Crutzen was a Dutch meteorologist and atmospheric chemist. He and Mario Molina and Frank Sherwood Rowland were awarded the Nobel Prize in Chemistry in 1995 for their work on atmospheric chemistry and specifically for his efforts in studying the formation and decomposition of atmospheric ozone. In addition to studying the ozone layer and climate change, he popularized the term Anthropocene to describe a proposed new epoch in the Quaternary period when human actions have a drastic effect on the Earth. He was also amongst the first few scientists to introduce the idea of a nuclear winter to describe the potential climatic effects stemming from large-scale atmospheric pollution including smoke from forest fires, industrial exhausts, and other sources like oil fires.

Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earth's atmosphere and that of other planets is studied. It is a multidisciplinary approach of research and draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology and volcanology and other disciplines. Research is increasingly connected with other areas of study such as climatology.