Source apportionment studies of air pollution aim to determine the sources of ambient particulate pollution, volatile organic compounds and other gases in the atmosphere. Receptor-oriented models (RMs) have become increasingly popular source apportionment methods among the research community and environmental protection agencies in the past two decades. RMs are designed to identify and quantify the measured mass of an atmospheric pollutant at a given site (the receptor site) to its potential emission sources by applying multivariate analysis to solve a mass balance equation. The results of RMs on atmospheric species are essential to policymakers for designing more effective air quality management strategies to reduce the health and environmental impacts of air pollution. This session aims to discuss case studies on the application of RMs as well as improvements and new methodologies on source apportionment of air pollution.