■NPR是National Public Radio,即美国国家公共之声。节目以新闻及综述为主,是美国国内收听率最高的广播之声。

概述:It is known to all that the air pollution is detrimental to human health, but is there any benefits we can receive from these pollutants? Recently, researchers have discovered something that contravened our common sense.

Lisa Emberson
Stockholm Environment Institute
Richard Harris
Mahowald's results suggest that reducing those pollutants could be an even bigger problem than we'd 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. "This is something that is really poorly studied. I think that's the main point of the paper is we're really been ignoring this potentially important topic." And studying it is not easy because the effects aren't well understood. For example, nitrogen can be a fertilizer, but it can stunt plant growth when nitrogen comes out of the air in acid form. Lisa Emberson at the Stockholm Environment Institute studies those biological cycles and she says there are so many subtle effects, it's hard to be sure which ones will prove to be the most important. Right now, it seems we're much more likely to clean up aerosol pollution while increasing the amount of carbon dioxide in the air. So scientists, unfortunately, may have a chance to see how this inadvertent experiment on our planet starts to play out. Richard Harris, NPR News.