This integrating nephelometer is part of a collection of prototypes of devices that were patented by the University of Washington from the 1960s into the 1980s that relate to climate and atmospheric monitoring and measurement. This prototype, co-invented by Professor Robert Charlson (1936-2021), was used in a 1969 experiment at CalTech that was referred to by the participants as "The Great Smog Caper." The experiment demonstrated that the size distribution of particles in smog above Los Angeles is the same as that in Seattle. The nephelometer was used to characterize the smog optically. The US patent that was a result of this prototype was the first University of Washington patent to generate royalties for the institution. Robert Charlson was a research engineer at Boeing, an atmospheric and climate scientist, a professor at the University of Washington, and a pioneer in the field of climate change.