2017届浙江省富阳市高考英语阅读理解暑假练习（8）_高考复习指南

2017届浙江省富阳市高考英语阅读理解暑假练习（8）

　　【2017界广东省增城市调研试题

　　Nowadays, there is a heated debate on whether pollutants should be cleaned in the air. Cleaning up the air, while good for our lungs, could make global warming worse. And the pollutants still go up around the air, along with carbon dioxide.

　　These pollutants are called aerosols (气溶粒) and they include soot as well as mixtures of nitrogen(氮) and sulfur(硫) and other stuff into the air. Natalie Mahowald, a climate researcher at Cornell University, says so far, scientists have mostly tried to understand what those aerosols do while they're actually in the air.

　　"There are so many different kinds of aerosols," she says. "Some warm and some cool. But in fact, humans are giving out a lot of extra aerosols, and they tend to cool for the most part."

　　The aerosols reflect sunlight back into space, or keep us cool. But it turns out that's not all they do. These aerosols also influence how much carbon dioxide gets drawn out of the air by plants on land and in the sea.

　　"They can add nutrients, for example, to the oceans or to the land," Mahowald says. "But also while they're in the atmosphere they can change the climate, and thus that also can influence the amount of carbon, the land or the ocean can take up. So there are quite a few different ways that aerosols can act on each other."

　　Mahowald's results suggest that reducing those pollutants could be an even bigger problem than realized, when you consider that aerosols help remove carbon dioxide from the air by encouraging plant growth. Hard numbers on this effect are highly uncertain at the moment, but this could turn out to be quite significant.