So you can imagine the reaction when a recent USA Today investigation of air quality around the nation's schools singled out those in the smugly green village of Berkeley, Calif.
In reaction to the phenomenon, some people called for raising the air pollution tax.
为了应对这一现象，有人要求增加空气污染税。
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Mark Hempsell, future programs director at Reaction Engines Ltd, told CNN: 'The engine starts by burning hydrogen with air and finishes up burning hydrogen with liquid oxygen like a shuttle engine.'