Early history and rationale for outdoor chamber work at the University of North Carolina

Environmental context Imagine in 1968 having to tell the largest cities in the US that they would have to spend billions of dollars to reduce human exposure to a gas in their air that no one emitted and that no one knew for sure how it came to be there. This history recalls how scientists and policy makers met this challenge so that by 1985 effective programs were in place. Abstract The University of North Carolina (UNC) outdoor chamber facility was established in 1972. The chamber produces reliable and interpretable results using ambient sunlight, temperature and weather, providing an effective physical model system for learning about atmospheric chemistry. This article recounts the 40-year history of the chamber facility, from the early days in understanding ozone–precursor relationship to the latest in studying gas and particulate toxicities on human lung cells.