Section 109 of the Clean Air Act directed the EPA Administrator to establish national ambient air quality standards (NAAQSs) for air polluants which endanger public health or welfare.

• 《洁净空气法案》的第109条责令联邦环境保护局局长针对威胁公共健康和公共福利的空气污染制定一个《全国环境空气质量标准》。