A range of bubble and sea spray aerosol generators has been tested in the laboratoryand compared with oceanic measurements from the literature. We have shown that themethod of generation has a significant influence on the properties of theaerosol particles produced. Hence, the validity of a generation system to mimicatmospheric aerosol is dependent on its capacity for generating bubbles and particlesin a realistic manner. A bubble-bursting aerosol generator which produces bubbles bywater impingement was shown to best reproduce the oceanic bubble spectral shapes,which confirms previous findings.Two porous bubblers and a plunging-water jet system were tested as bubble-burstingaerosol generators for comparison with a standard nebulizer. The methods for aerosolproduction were evaluated by analysing the bubble spectrum generated by the bubble-burstingsystems and the submicron size distribution, hygroscopicity and cloud condensationnucleus activity of the aerosols generated by the different techniques. Significantdifferences in the bubble spectrum and aerosol properties were observed when usingdifferent aerosol generators.The aerosols generated by the different methods exhibited similar hygroscopicity andcloud condensation nucleus activity behaviour when a sample of purely inorganic saltswas used as a parent seawater solution; however, significant differences in the aerosolproperties were found when using samples of filtered natural seawater enriched withbiogenic organics. The presence of organics in the aerosol caused suppression of thegrowth factor at humidities above 75% RH and an increase in the critical supersaturationwith respect to the generation from artificial seawater devoid of organics. The extent ofthe effect of organics on the aerosol properties varied depending on the method of particleproduction. The results of this work indicate that the aerosol generation mechanism affectsthe particles organic enrichment, thus the behaviour of the produced aerosols strongly dependson the laboratory aerosol generator employed.Comparison between bubble lifetimes in several laboratory simulations and the oceanic conditionsindicated that it would require a considerable extension of the dimensions of the currently usedbubble-bursting laboratory systems in order to replicate the characteristic oceanic bubblelifetimes. We analyzed the implications derived from the reduced bubble residence times inscaled systems, regarding marine surfactants adsorption on rising bubbles, and found thatadsorption equilibrium is reached on a timescale much shorter than the bubble lifetime insmall-scale laboratory generators. This implies that adsorption of marine surface-activematerial is not limited by surfactant transport to the bubble surface.
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