Cloud condensation nuclei activity of fresh and aged submicrometer maleic acid aerosol particles.

Arden M. Floyd, Elaina Berger, Chloe Ayala-Hadden, Emily Nortmann, Nath-Eddy Moody, Brett Young, Skylar Gootkin, Denisia M. Popolan-Vaida

Department of Chemistry, University of Central Florida, Orlando FL, U.S.

Atmospheric aerosols are suspensions of liquid, solid, or mixed particles with highly variable chemical composition and size distribution. Their variability is due to the numerous natural and anthropogenic sources and varying formation mechanisms. Combustion represents an important source of aerosols in the atmosphere with dramatic impacts on the chemical composition of the atmosphere and the mechanism of clouds formation. Here we report the reactivity and cloud condensation nuclei (CCN) activity of maleic acid (MA) aerosol particles that are released in atmosphere as a result of combustion processes. The reactivity of MA with ozone and its CCN activity before and after the reaction with ozone is investigated in a flow tube reactor in conjunction with a high-resolution mass spectrometer, a scanning mobility particle sizer and a CCN counter. MA particles are found to react with ozone and the reactive uptake coefficient appears to have no dependence on particle diameter. The CCN activity of MA particles dramatically increases after the reaction with ozone. This study emphasizes the importance of investigating the rate of change in CCN activity of dicarboxylic acids under the combined effects of several atmospheric parameters as oxidants and relative humidity to accurately describe their role in cloud formation.