The effect of organic matter on CCN properties of particles produced in laboratory simulations of bubble bursting

In this study, we measure the submicron size distributions and cloud condensation nucleus properties of aerosol particles produced from a laboratory system that simulates particle formation from bubble bursting. The experimental method consists of a plunging water jet into a stainless steel tank filled with 10 L of artificial seawater, with and without added organic compounds. The tank is equipped with a water pump that can be set at variable speeds. Preliminary results from size distribution measurements agree with previous studies, in that the number concentration and size of particles produced depend on the water jet flux. Observations of cloud condensation nucleus (CCN) activity are also affected by the water pump speed. The CCN activity of artificial seawater, at a salinity of 35‰ and with no added organic compounds, is similar to that of pure sodium chloride. Addition of as much as 1 g/L of D-mannitol does not considerably alter the particle size distribution, nor does it alter the observed CCN activity. Addition of less than 5 mg/L of the surfactant sodium dodecyl sulfate leads to shifts in size distribution roughly similar to those from published results, in which other methods of simulating bubble bursting were used. The growing use of experimental methods for the reproduction of bubble bursting in aerosol laboratories gives us reason to explore possible differences in the properties of particles generated from similar systems. Comparisons between observations from the above-mentioned 10-L tank and those from a larger tank filled with approximately 100 L of identical artificial seawater will also be presented.