Physicist and meteorologist. Born in Falkirk, the son of a lawyer, Aitken studied at the University of Glasgow. He is known for his research work on atmospheric dust, the formation of dew, cyclones and evaporation. Working from a laboratory in his Falkirk home, he invented an instrument to detect atmospheric dust particles, called a koniscope. He was able to show the importance of such particles in the process condensation of water from clouds and fogs to form rain and dew.
Aitken was rewarded with an honorary doctorate from his alma mater in 1889.
He died in Falkirk and is remembered in the term Aitken Nuclei, which are numerous small atmospheric particles formed as a product of combustion.