The Clean Air and Building Infrastructure Improvement Act seeks to amend the Clean Air Act regarding preconstruction permits. It urges the timely issuance of regulations and guidance for implementing national ambient air quality standards and specifies that the 2024 Primary Annual Particulate Matter2.5 Standard shall not apply to the review and disposition of a preconstruction permit application under certain conditions. It clarifies the definitions of terms such as "best available control technology" and "lowest achievable emission rate." The Act aims to streamline the permitting process while ensuring compliance with emissions requirements.