Measurements of radon-222 (222Rn) concentration were collected using a 1500 L dual-flow loop radon detector, designed and built by the Australian Nuclear Science and Technology Organisation (ANSTO; Lucas Heights, NSW, Australia) (Chambers et al., 2011; Whittlestone and Zahorowski, 1998). Sampling occurred at 65-75 L min^-1. Calibration occurred during the campaign from a Pylon (Ottawa, ON, Canada) source. Measurements were taken at Cataract Scout Park, Appin, N.S.W. (34°14'42.29"S 150°49'24.97"E) from an inlet 3.94 m above ground level as part of the Characterizing Organics and Aerosol Loading over Australia (COALA-2020) campaign. The campaign ran from mid-January to mid-March, 2020. Reported measurements are at 30-minute time resolution. Concentrations have not been corrected for the response time of the detector but can be on the request of users. See Griffiths et al. (2016) for details.

COALA-2020 was funded by Australia's National Environmental Science Program through the Clean Air and Urban Landscapes hub