Since the 1980s, most people who did not own a brand new car had to stop off every year at a car emission station, pay a fee and make sure their car passed a test.

These tests were designed to lower the amount of pollutants coming out of your car’s tailpipe. The tests came after the Treasure Valley’s air quality dropped below federal standards.

Now, the emission tests are going away and we wanted to find out why. So we asked Ian Max Stevenson, who covers the city of Boise and climate change for the Idaho Statesman.