. . . . . . . . . . . "Concentration of soluble thorium {soluble_Th CAS 7440-29-1} per unit volume of the atmosphere [aerosol <1um phase] by filtration, leaching with pH 4.7 ammonium acetate buffer"@en . . . . . "soluble_Th_aerosol_NH4AC_Leaching_<1um" . . "SDN:P01::AEC079CC" . "accepted"@en . "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 . . . . . . .