Online Water‑Soluble Iron Speciation in Ambient Aerosols under Cloud-Water Relevant and Neutral Conditions

This dataset contains online measurements of water-soluble iron in airborne particulate matter obtained using a newly developed spectrophotometric method based on detection of the magenta iron–ferrozine complex. The method was deployed during two field campaigns in Berlin and evaluated with two different sampling systems- the Metrohm AeRosol Sampler (MARS) and the Particle Into Liquid Sampler (PILS). Both systems operated reliably under field conditions. In addition to iron speciation data, the dataset includes particle mass and number size distribution measurements from ELPI+ (Dekati, Finland) and black carbon (BC) concentrations measured with an aethalometer (MA200, AethLabs, USA).