"Concentration of soluble iron {soluble_Fe CAS 7439-89-6} per unit volume of the atmosphere [aerosol <1um phase] by filtration, leaching with pH 4.7 ammonium acetate buffer"@en . . "SDN:P01::AEC049CC" . "The amount (mass or moles) of the specified chemical entity contained in aerosols within the specified size fraction isolated from a volume of atmosphere using the specified method."@en . .