PNNL

Abstract

Atmospheric mineral dust particles represent a major component of tropospheric aerosol mass and provide a reactive surface for heterogeneous reactions with trace atmospheric gases (Dentener et al. 1996).Heterogeneous processes alter the chemical balance of the atmosphere and also modify the physicochemical properties of mineral dust particles (Bauer et al. 2004). Organic and inorganic vapors can react with or partition to dust particles and alter their chemical composition (Al-Hosney et al. 2005; Laskin et al. 2005a, 2005b; Liu et al. 2008; Sullivan et al. 2007, 2009a; Sullivan and Prather 2007; Usher et al. 2003). Calcite (CaCO3) is one of the most reactive components of mineral dust, readily reacting with acidic gases. The fraction of CaCO3 in total dust mineralogy displays large variations between desert regions and other regions of the world as well as between individual mineral particles (Claquin et al. 1999; Jeong 2008; Laskin et al. 2005b; Sullivan et al. 2007). Through reactions with acidic gases CaCO3 can be converted to soluble hygroscopic products including CaCl2 and Ca(NO3)2, and sparingly soluble, non-hygroscopic products including CaSO4 and CaC2O4 (Krueger et al. 2004; Liu et al. 2008; Sullivan et al. 2009a, 2009b).