摘要
污染，就其定义而言，是指某些物质进入环境并对其造成有害的破坏。大自然有时会自发生成破坏性污染物，比如野火会产生滚滚的浓烟和灰烬，火山会喷射出有毒的气体。然而，对当今全球蔓延的大部分污染负有责任的都是人类。无论走到哪里，我们似乎都习惯于留下垃圾和废弃物。即使前往地球上最偏远的边区村落，你都能亲眼看到这一点。然而，地球是一个广袤之地，是否还有未破人类污染的最后阵地呢？要想完满地回答这个问题，我们可以将环境划分为四个领域——天空、陆地、淡水和海洋。
Pollution, by definition, is something introduced into the environment that harmfully disrupts it. While nature sometimes produces its own damaging contaminants--wildfires send up billows of smoke and ash, volcanoes belch noxious gases-- humans are responsible for the lion＇s share of the pollution plaguing the planet today.Wherever we go, we seem to have a knack for leaving our rubbish and waste behind. Visit even the most remote outpost on the planet and you will witness this first hand Still, the world is a big place. Might there be some last holdouts free from the taint of our pollution？ Answering that question works best if we break down the environment into four realms--the sky,land, freshwater and ocean.
