Environmental groups sue the EPA to enforce air quality laws in Missouri

Missouri and Illinois are among dozens of states that have yet to submit plans for improving air quality in protected areas. Environmental nonprofits are suing the EPA to compel the agency to take action.
Several of the largest conservation nonprofits in the U.S. claim in a federal lawsuit that the Environmental Protection Agency has failed to enforce air quality standards.

As part of the Clean Air Act, every state must submit a detailed plan to the EPA every 10 years for reducing air pollution in national parks and wilderness areas. Nearly three dozen states, including Missouri and Illinois, have not submitted updated plans to the EPA — and environmental advocates hope to compel the federal agency to take action.

Haze forms when sunlight hits tiny particles of air pollution, creating a smog-like curtain that reduces visibility.