Trivalent chromium is a trace nutrient essential to human beings while hexavalent chromium is a known carcinogen and was among the 18 core hazardous air pollutants defined in 2004 by the US EPA. A new conceptual model of Cr speciation in deliquesced particles (pH 4) has been developed. The model provides new information on the soluble and insoluble forms of Cr in atmospheric PM. The dominant form of Cr(VI) in the solution was found to be Cr2O7 2−. CrO4 2− was produced by the dissolution of Na2CrO4(s) and K2CrO4(s) available in the solid core, but a considerable portion of the CrO4 2− precipitated as (NH4)2CrO4(s), CaCrO4(s), BaCrO4(s), and PbCrO4(s). Cr(OH)3 was found to be soluble, and the insoluble form of Cr(III) was Cr2(SO4)3. Conversion of Cr(VI) to Cr(III) was higher than the conversion of Cr(III) to Cr(VI). The simulation results agree with the field measurements near Cr industries.
- Atmospheric PM
- Conceptual model
- Insoluble and soluble Cr
ASJC Scopus subject areas
- Atmospheric Science
- Management, Monitoring, Policy and Law
- Health, Toxicology and Mutagenesis