"Concentration of soluble barium {soluble_Ba CAS 7440-39-3} per unit volume of the atmosphere [aerosol phase] by filtration, leaching with pH 4.7 ammonium acetate buffer"@en . . "SDN:P01::AEC133CC" . "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 . .