MO HB1924

Amends Missouri air quality law (section 643.020) to include "light" in the definition of "air contaminant" under the state's air pollution control framework.

Creates the "Night Sky Protection Act" (section 643.630) to reduce light pollution at Missouri protected places including state parks with overnight camping, wilderness areas, wildlife refuges, scenic riverways, and designated military training areas.

Establishes voluntary guidelines for the Air Conservation Commission to reduce night sky luminance at protected places to specific percentages of natural nighttime sky luminance by 2025, 2040, and 2055.

Requires the commission to determine natural nighttime sky luminance levels for each protected place, develop sky luminance forecasts for one, five, and ten-year periods, and annually report measurements in microcandela per square meter.

Exempts the Night Sky Protection Act from enforcement provisions until federal Clean Air Act requirements become stricter than this state law.