Indoor dust is an important matrix for persistent organic pollutants and endocrine disrupting chemicals in indoor environments. It is useful as a matrix for sampling and comparing concentrations between indoor environments, and is also of concern as a potentially large exposure route, particularly for infants and young children. Thus, it is important to have a good understanding of the distribution of chemicals in indoor dust. Major gaps in our understanding of indoor dust are regarding how variable the concentrations are within a given room (e.g. is one individual sample from a room representative of the whole room, or is there large variability within rooms) and how strongly concentrations are affected by proximity to local sources. While the spatial variability in dust is relevant in assessments of many chemicals, for the purposes of this study we will be assessing the variability with respect to polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (nBFRs) as these chemicals represent a range of use statuses (e.g. some banned, some in process of phase-out, some in current use) and have direct indoor sources. The overall goal of this study will be therefore to determine the variability of PBDEs and nBFRs in indoor dust samples in residential and workplace rooms, and relate the variations in concentration to the point of sample collection in the room and the sampling technique.