Section 243.102  Scope

a)         This Part sets forth the NAAQS adopted by USEPA under section 109 of the CAA (42 USC 7409) and incorporated into this Part under Sections 7.2 and 10(H) of the Act.

b)         National primary ambient air quality standards (primary NAAQS) define levels of air quality that USEPA has judged are necessary, with an adequate margin of safety, to protect the public health.  National secondary ambient air quality standards (secondary NAAQS) define levels of air quality that USEPA has judged necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant.  These standards are subject to revision, and additional primary and secondary NAAQS may be promulgated as USEPA deems necessary to protect the public health and welfare.

c)         The promulgation of primary and secondary NAAQS must not be considered in any manner to allow significant deterioration of existing air quality in any portion of this State.

BOARD NOTE:  Derived from 40 CFR 50.2.

(Source:  Amended at 45 Ill. Reg. 337, effective December 17, 2020)