Bunuel
Environmental officials in Velonia note that the share of national emissions attributed to passenger vehicles has declined from 27 percent to 19 percent over the last decade. They cite this trend as evidence that stricter vehicle standards have been effective in reducing overall air pollution. However, satellite readings over the same period show that Velonia’s total particulate pollution has actually increased.
Which of the following, if true, most seriously weakens the officials’ reasoning?
A. Vehicle kilometers traveled rose sharply as Velonia’s population grew, while per-kilometer emissions from new cars fell, leaving total passenger-vehicle emissions roughly unchanged.
B. During the same decade, Velonia implemented incentives for electric vehicle adoption, though these vehicles still make up a small share of the national fleet.
C. Five years ago, the national inventory reclassified emissions from ride-hailing fleets and small delivery vans from “passenger vehicles” to “light commercial transport,” without any change in their emission levels.
D. Peak-hour traffic fell in several city centers after congestion fees were introduced, though off-peak traffic increased in suburban corridors.
E. Regional cross-border haze events became more frequent, raising measured ambient pollution in Velonia during several recent years.
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Going through the passage to understand what it says:
Sentence 1: Passenger vehicle emissions have gone down from 27% to 19% in the past decade.
Sentence 2: Officials say this is because they put in stricter vehicle standards.
Sentence 3: Yet, there's more air pollution now somehow.
While the question stem reads as "Weaken the Argument", this is actually a paradox we need to resolve. We need to find a question option that most cleanly explains how these two seemingly-opposing results could have happened. Now, lets go through the options.
Option A: This essentially says "population grew, more cars on the road, so vehicle emissions didn't actually change." This is so tempting, but note the last part. It doesn't explain why emissions
increased. Eliminate.
Option B: Electric vehicles are on the road now, albeit in a small amount. This would actually be more of a strengther for the officials' explanation, and doesn't solve the paradox at all. Eliminate.
Option C: A significant part of the passenger vehicles are now reclassified as light commercial transport. These vehicles are on the road a lot as they drive for a living, therefore the contribute to air pollution, but now they've been transplanted from one category to another without any change in their actual emissions. The reduction in passenger vehicle emission and yet increasing air pollution now makes perfect sense. Let's hold onto this one.
Option D: This doesn't resolve the paradox at all, because emissions would probably remain equal.
Option E: This doesn't explain the reduction in passenger car emissions. Eliminate.
We're left with Option C, which is the answer.