Changes to Tailpipe Testing

The Colorado Air Pollution Control Division is proposing changes to Denver's tailpipe testing program. The notice is posted online, but the 153 page document is probably the last thing you want to read right now.

Tailpipe testing is one of three ways that air pollution from cars and trucks is kept in check. First off, vehicle manufacturers have to ensure that cars and trucks meet federally established fuel mileage standards and are built with pollution controls installed. Second, oil refiners have to ensure that gasoline and diesel only contain so much sulfur, so much lead, so much oxygen, and so on, so that when they're burned, the pollution is less severe. And third, there's tailpipe testing to pick up the slack, meaning it's supposed to target older, dirtier, or less maintained cars that are spewing the most pollution.

But the state thinks tailpipe testing could be better in Denver. It's now proposing to use remote sensing to "clean-screen" supposedly "clean" vehicles. The screening process would allow vehicles to avoid testing if remote sensing finds them to be "clean."

The goal of the proposed changes are to make tailpipe testing more efficient and cost-effective. These are admirable goals, but really the goal of tailpipe testing is to protect us from air pollution. It causes some concern when the need to reduce air pollution is not driving changes to clean air rules.

At this point, it's hard to tell what the impacts of the proposed changes are going to be to clean air. A rulemaking hearing is set for June of this year. Stay tuned for more information and updates.