A protocol for the comprehensive evaluation of greenhouse gas and air pollutant emissions from shopping

The global retail sector considerably contributes to climate change and air pollution through greenhouse gas (GHG) and air pollutant emissions associated with shopping activities—including freight transport, consumer travel, and packaging use. While prior studies have estimated these emissions, they hinder cross-study comparisons, limiting both scientific understanding and the development of effective mitigation strategies. To address this gap, we present a standardized protocol for comprehensive and consistent assessment of GHG and air pollutant emissions from shopping. Demonstrated through case studies on three major merchandise categories in China, our approach improves upon existing work by offering greater comprehensiveness, national representativeness, and temporal coverage. An agent model for emission calculation was built based on this protocol to provide ground-truth logic of retail activities for artificial intelligence agents, enabling emission calculations under varying consumer and supply-chain scenarios. We propose this protocol as a robust framework to enable comparable, transparent evaluations across shopping methods, product categories, regions, and time periods—thereby advancing evidence-based strategies for sustainable retail transformation.