Records relate to research carried out by Viitala and colleagues at Lakehead University as part of the Acidic Precipitation In Ontario Study. Field research was done at Hawkeye Lake northwest of Thunder Bay, and at Pukaskwa National Park. The records include data, photographs, reports and research papers. Some records also relate specifically to the International Symposium on Acidic Precipitation held at Muskoka on September 15-20, 1985.

Records date primarily 1980-1988, with some additional documents from 2018 and 2022.