"Concentration of soluble thorium {soluble_Th CAS 7440-29-1} per unit volume of the atmosphere [aerosol phase] by filtration, water leaching"@en . . "SDN:P01::AEC084CC" . "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 . .