Senate Bill 491 Summary

• Requires new or renewal air quality permits to include a plan for reducing emissions during winter thermal inversion action days (November through March) in the permit's geographic area.

• Mandates permittees to comply with their emission reduction plans when a winter thermal inversion action day is declared and to promptly report compliance steps to the department.

• Limits emissions averaging periods for November through March to a maximum of 8 hours, with exceedances not totaling more than 1 hour during that 5-month period.

• Defines "thermal inversion" by reference to section 5543 of the Natural Resources and Environmental Protection Act.

• Takes effect 90 days after enactment, contingent on Senate Bill 490 also being enacted into law.