Smog tests with human subjects

On June 28, 1956, chemical engineer Edward Liston, right, of the Stanford Research Institute in South Pasadena, checks five subjects in a smog chamber, breathes in the reconstituted smog, and takes note of their reactions.

The exhaust gases are provided by an ordinary automobile, hooked to its engine which goes through typical phases of idling, acceleration, cruising and deceleration.