Self-study
Automobile-emission standards are enforced through annual inspection. ██ █████ ███████████ ████ ███ ██████ █████ ███████ ████ ███ ████████ █████ ████ █████ ███████ ████████ ███████ ███████ ███████ ███ ██████ ██ ███████ ██████████ ██ ███████ █████ █████ ███ ████ █████
Summarize Argument
The stimulus itself doesn’t provide an argument, but the question stem asks us why current automobile-emission enforcement may not be effective in controlling pollution. In other words, we need to weaken the conclusion that current enforcement is effective. The method of enforcement (i.e. the support for that conclusion) is that pollutant levels in exhaust are measured while a car is idling.
Notable Assumptions
The conclusion we’re weakening assumes that cars emit similar or higher levels of pollutants while they’re idling than while they’re in motion. In other words, it assumes that a test while a car is idling will not find a significantly lower pollutant level than the car emits while being driven.
24.
Which one of the following, ██ █████ ████ ████████ █████████ ████ ███████ ███████████ ██ ███████████████████ █████████ █████ ██ ███████████ ██ ███████████ ███████ █████████ ███████
a
As an emission-control ██████████ ██████████ ███ ███████ ███ ██████████ █████ ██ █████████████ ██████ █████████████ ████ ██████████
This does not undermine the effectiveness of current enforcement, because the expense of continuing to improve emission-control technology has nothing to do with how reliable emission-control testing is. This is just irrelevant to the conclusion we’re weakening.
b
The testing devices ████ ████ ██ ████████████ ██████████ ██ ███████ █████████ ██████ ████ ██████████ █████████
This does not undermine the effectiveness of current enforcement, because we can’t assume that the testing devices are not frequently recalibrated. It’s equally possible that they are frequently recalibrated, in which case current enforcement seems fine.
c
The adjustments needed ██ ████ █ ███ ████ ███████ ████ ██ ██████ ████ ███ ███ ████ ████ ████ ██████ ██ ██████████ ████ ██████ ██ ███████ ███████
This undermines the effectiveness of current enforcement by rebutting the assumption that emissions are similar when idling and when in motion. If passing the test by idling cleanly then leads to higher highway pollution, that’s not an effective enforcement method.
d
Most car owners ███ █████ █████████ ██ ████ ████ ████ █████ ████ ███ ██ ██████████ ████ ████████ ██████████
This does not undermine the effectiveness of current enforcement. All this tells us is that most people want to pass the control test, not whether or not the test actually works. This is irrelevant to whether or not current enforcement is effective.
e
When emission standards ███ ████ ██ ██████████ ███ ████ ███ █████ █████
This does not undermine the effectiveness of current enforcement. Just knowing that older cars don’t get a free pass doesn’t help us figure out whether current emissions testing is doing its job. This is irrelevant.