Welcome to the catalogue of EHEN: European Human Exposome Network. The European Human Exposome Network (EHEN) is the world’s largest network of projects studying the impact of environmental exposures across a lifetime - the exposome - on human health. Collectively, the EHEN projects are working in 24 countries across Europe and the USA. There are over 100 data sets being used including cohorts, cross-sectional studies, biobanks, randomised controlled trials (RCTs), case control studies and health or occupational registries..