St. Louis air quality just got a 'Serious' downgrade, forcing new pollution controls

The US environmental regulators have formally declared that the Missouri side of St. Louis failed to meet 2015 ozone air quality standards. This automatically reclassifies the area to "Serious" nonattainment, requiring stricter pollution controls.

When an area fails to meet air quality targets, it triggers a legal process that forces local governments and industries to take more aggressive action. This reclassification means St. Louis will have to implement new, more expensive measures to reduce ozone pollution. This includes things like tighter emissions limits for factories and power plants, and potentially new rules for vehicle inspections.