虽然有时候我会想念小镇新鲜的空气及安静的生活，但没有什么可以弥补都市提供给我的机会。

Although I sometimes miss the fresh air and quiet life of a small town, nothing can make up for the opportunities that the city offers me.

youdao

洛杉矶不仅是全美国第二大都市，它污浊的空气，在美国也是名列前茅。

Los Angeles is not only the second-largest city in the United States, but it also ranks high for having some of the dirtiest air in the U.S..

youdao

北京是空气污染严重的大都市。

Beijing is a heavy polluted metropolis. There are 3 reasons as followed.

youdao

So, if you want to attack urban air quality, this is probably moving in the wrong direction, OK?

所以如果你想攻击都市的空气质量，这可能是一个错误的方向，对吗？

麻省理工公开课 - 固态化学导论课程节选