By Maria Hickey, KWMU
St. Louis – 
Nearly 700,000 cars and small trucks in the St. Louis region had exhaust tested for pollutants last year as part of the Gateway Clean Air Program.
The $24 test required every other year is one way the area is trying to meet the EPA's air quality standard.
But since 2000 when it went into effect in the City of St. Louis and four surrounding counties, there have been several efforts in the state legislature to end it. KWMU's Maria Hickey looks at the latest attempt