Dataset: Number and mass production efficiencies of primary marine aerosol (PMA) generated from seawater near the BATS station during the R/V Atlantic Explorer cruises AE2113 (July 2021) and AE2303 (January 2023)

Particles were generated using a high-capacity marine aerosol generator. Briefly, the generator consists of a 20 centimeter (cm) diameter model ocean-atmosphere system entirely made of borosilicate glass and Teflon. The "ocean" holds ~40 liters (L) of seawater, with a total depth of 90 cm. Unmodified seawater from the ship’s clean seawater line, ~3 meters (m) below the sea surface, was continuously pumped at 4 liters per minute (L min-1) into the bottom of the generator. Seawater continuously drained over the annular rim, constantly refreshing the surface of the "ocean" and preventing the formation of bubble rafts. Seawater from the base of the generator was pumped through the conical inlet of the Venturi at a flow rate of 3 L min-1. Hydrated ultrapure air was pumped through two ports at the constricted throat of the Venturi at a combined air flow rate of 5 L min-1.

The Venturi produced bubbles at a depth of 74 cm below the air-water interface. Bubble bursting at the air-water interface emitted mPMA into the model "atmosphere" of the generator. The model atmosphere is the 97-cm deep, open headspace above the water surface. Ultrapure hydrated sweep air flowed through the headspace above the water surface at 70 L min-1 and transported particles for sizing. Air was sampled through three glass ports at the top of the generator at ~6 L min-1 for the particle sizing instrumentation. Sweep air at a flow rate of 70 L min-1 was hydrated and maintained at ~80% relative humidity by modulating the temperature applied to the mist chambers.

To measure particle numbers and sizes, air was sampled from the glass port in the generator's headspace directly to a custom-fabricated, 46 cm length, diffusion dryer with 1.91 cm inner diameter stainless steel mesh. This air was directly pulled into the Aerodynamic Particle sizer (APS; TSI Model 3321) at a rate of 4 L min-1 for the sheath flow and 1 L min-1 for the sample flow. Prior to entering the APS, air was sub-sampled at a flow rate of ~0.5 L min-1 to the Scanning Electrical Mobility Spectrometer (SEMS; Brechtel Manufacturing, Inc. Model 2100) using a custom-fabricated, stainless-steel splitter (1.59 cm ID with a 0.476 cm ID sidearm sampling port). After passing through the 1 micrometer (µm) size-cut impactor, air flowed through an additional Nafion dryer, before entering the SEMS neutralizer.