— Among cities across the United States, St. Louis ranks among the worst in terms of clean air.

A study released Thursday by Environment Missouri suggests St. Louis had 23 days in which air quality was deemed dangerous to breathe, placing the city 7th among large metro areas across the country.

On 18 other days in the St. Louis area, the study says the amount of smog in the air was also dangerous, but did not meet the federal threshold for reporting.

“Missourians deserve clean air. But on far too many days, people in the St. Louis area are exposed to dangerous smog pollution,” said Ted Mathys, State Advocate with Environment Missouri.

Experts suggest smog, an air pollutant, leads to asthma attacks and makes respiratory awareness worse, especially among children and the elderly.

The group wants legislative action from Washington, and expressed frustration with the Obama administration’s decision to hold off on new smog standards through the Environmental Protection Agency.

“Unfortunately, rather than acting decisively to protect our kids from dangerous air pollution, President Obama chose to kick the can down the road. Missouri’s kids, senior citizens and those suffering from respiratory problems will suffer as a consequence and certainly deserve better, said Mathys. “President Obama and Missouri’s members of Congress should stand up for Missourians’ health and oppose any attacks to the Clean Air Act.”

Across the state, Missouri had 25 smog days in 2010, most in St. Louis, but others in Kansas City, Joplin, and St. Joseph. Kansas City ranks 35 on the same list.

A spokesperson for the City of St. Louis was not immediately responsive to a request for comment Wednesday evening.