This repository contains the data used in the study “Estimating Ambient PM₂.₅ in Urban and Rural Southwestern Uganda using Ground-Based Sampling and Global Exposure Data Sets.” The dataset includes ground-based PM₂.₅ measurements collected at five sites (urban and rural) in southwestern Uganda over one year, and estimates from global exposure datasets ACAG and MERRA CNN. The data support the assessment of spatial and seasonal variation in ambient PM₂.₅ concentrations and comparison of ground-based measurements with global exposure estimates.