cc-by-4.0Kulmala, Markku2025-04-292017-11-152017-11-15https://datakatalogi.helsinki.fi/handle/123456789/5942Data that is presented in the publication "The role of ions in new-particle formation in the CLOUD chamber", ACP 2017.The role of ions in new-particle formation in the CLOUD chamber: supporting datadataset