Aerosol production from the surface of the Great Lakes

Abstract

While much is known about marine aerosol generation, little is known about aerosol produced from breaking waves in large freshwater environments or about what implications this aerosol may have for air quality and climate. We present here evidence of significant particle production from the surface of the Great Lakes. In 2009, vertical profiles of the submicron particle size distribution were measured over Lake Michigan, where we found substantial increases in ultrafine particle concentrations with the source at or near the lake surface. The Aitken mode aerosol concentration exhibits an exponential correlation with wind speed, suggesting that breaking waves along the surface were causing the observed particle formation. A calculated dry particle size distribution based on analysis of the lake water shows reasonable agreement with our observed size spectra. This new particle production source is previously un‐studied and could significantly impact atmospheric composition in the region surrounding fresh water lakes.

Regional impacts of ultrafine particle emissions from the surface of the Great Lakes

“…The available evidence strongly suggests that these particles were the result of natural, wave breaking processes at the lake surface. As described by Slade et al (2010), the particles were only observed when whitecap waves were present, the concentration of the 15-40 nm mode was in most cases largest just above the surface, and the concentration of that mode increased exponentially with surface wind speed. Furthermore, a chemical analysis of the lake water indicated that the concentrations of trace constituents (Table S1 of Slade et al, 2010) were cumulatively sufficient to produce a dry particle mode in the 15-40 nm size range if the size distribution of water-containing droplets emitted from the lake surface were similar to that observed in marine environments.…”

“…On the other hand, Slade et al (2010) did indicate that the lake surface source was potentially significant in terms of particle number, comparable to the low end of the range of atmospheric new particle formation rates. Nilsson et al (2001) measured marine particle fluxes on the order of 10 6 m −2 s −1 at atmospherically relevant conditions (wind speed = 10 m s −1 , height = 10 m); averaged through the lowest 100 m of the atmosphere, this would correspond to a new particle source rate of ∼0.01 cm −3 s −1 .…”

“…A thorough discussion of these and many other natural sources of particulate material in the atmosphere can be found in the review by Carslaw et al (2010). Slade et al (2010) recently described another new source of natural particles that is potentially significant on regional scales-the production of nanoparticles from breaking waves at the surface of freshwater lakes. In Summer 2009, the Purdue University Airborne Laboratory for Atmospheric Research (ALAR) research aircraft conducted several research flights over the northern parts of Lakes Michigan and Huron in support of the Community Atmosphere-Biosphere Interactions Experiment (CABINEX).…”

“…While the particle production mechanism proposed by Slade et al (2010) is interesting, it has not yet been definitively established-that would require a more targeted experiment with a more robust set of observations. Moreover, it…”

Aerosolization of Ebola Virus Surrogates in Wastewater Systems

“…Studies of oceans and lakes have shown that aerosols may be produced by bubble bursting and breaking waves, 43,44 and such processes may be active, though at smaller scale, in a sewer system. To the best of our knowledge, this study is the first to investigate the aerosol size distribution produced by converging sewer pipes.…”