Tom Carper actually said...

A wall would fix that pollution problem with Mexico, a big wall.

On similar ground, do you think it makes sense for the EPA to consider cost when establishing a health standard?

As Robert Frost used to say, 'We have miles to go before we sleep.'

Arbitrarily delaying implementation of the 2015 ozone NAAQS to 2025 would leave the 2008 standard which has been found to be outdated.