Environmental protection: air pollution; calculation of emission profile data; modify. Amends sec. 5503 of 1994 PA 451 (MCL 324.5503).

HB 5557 amends Michigan's environmental law to require the state environmental agency to use the longest time period permitted under the federal Clean Air Act when calculating pollution emissions data for the state's inventory. This change directly affects the Michigan Department of Environment, Great Lakes, and Energy, which collects emissions data from businesses and industries. The bill specifically adds a requirement that the department must use the longest federal time period authorized for emissions rate calculations, aligning state reporting with federal standards. This adjustment aims to improve the accuracy and consistency of Michigan's air pollution data.