The Sydney Particle Study involved the comprehensive measurement of meteorology, particles and gases at a location in western Sydney during February-March 2011 and April-May 2012. The aim of this study was to increase scientific understanding of particle formation and transformations in the Sydney airshed. In this paper we describe the methods used to collect and analyse particle and gaseous samples, as well as the methods employed for the continuous measurement of particle concentrations, particle microphysical properties, and gaseous concentrations. This paper also provides a description of the data collected and is a metadata record for the data sets published in Keywood et al. (2016a, line"https://doi.org/10.4225/08/57903B83D6A5D">https://doi.org/10.4225/08/57903B83D6A5D) and Keywood et al. (2016b, line"https://doi.org/10.4225/08/5791B5528BD63">https://doi.org/10.4225/08/5791B5528BD63).