According to a new report from the Environmental Protection Agency, American cities are becoming less toxic and the air quality is slowly, but significantly improving.

Levels of major toxins such as benzene and mercury have fallen since the Clean Air Act Amendments of 1990, the EPA’s Urban Air Toxics Report stated.

Apart from the reduction of benzene and mercury levels, lead in the air has also decreased 84 percent since 1990, the EPA said.

“This report gives everyone fighting for clean air a lot to be proud of because for more than 40 years we have been protecting Americans—preventing illness and improving our quality of life by cutting air pollution—all while the economy has more than tripled,”

EPA Administrator Gina McCarthy said in a press release.

The Agency has also stressed that they plan more actions that will further improve air quality in America.