The study finds urban air pollution has nearly doubled in 3,000 cities over the past two years.

研究发现，过去两年间有3000座城市的空气污染指数几乎翻了一倍。

Even before the Volkswagen scandal, policymakers had begun questioning the choice of diesel because of concerns over urban air pollution.

因为担心城市空气污染问题，在大众的丑闻发生以前，决策制定者就已经开始对选择柴油车提出了质疑。

Neira agrees in the report that " urban air pollution continues to rise at an alarming rate" and severely affects human health.

内拉认可报告中提及的“城市空气污染仍以惊人的速度上升”并且严重影响人类健康的观点。