N.Y. Comp. Codes R. & Regs. tit. 6 § 380-11.1
For each radionuclide, Table I of section 380-11.7 of this Subpart indicates the chemical form which is to be used for selecting the appropriate ALI or DAC value. The ALIs and DACs for inhalation are given for an aerosol with an activity median aerodynamic diameter (AMAD) of 1 µm and for three classes (D, W, Y) of radioactive material, which refer to their retention (approximately days, weeks or years) in the pulmonary region of the lung. This classification applies to a range of clearance halftimes for D of less than 10 days, for W from 10 to 100 days, and for Y greater than 100 days. The class (D, W, or Y) given in the columns headed class applies only to the inhalation ALIs and DACs given in Table I, columns 2 and 3. For each radionuclide, Table II of section 380-11.7 of this Subpart provides concentration values for airborne and liquid effluents released to the general environment. Table III of section 380-11.7 of this Subpart provides concentration limits for releases to sanitary sewer systems. The concentration values listed in Tables II and III of section 380-11.7 of this Subpart are used to control the release of radionuclides to the environment in such a manner that the total dose to an individual member of the public does not exceed the limits prescribed in Subpart 380-5 of this Part.
N.Y. Comp. Codes R. & Regs. Tit. 6 § 380-11.1