高溫天氣下樹木會污染環境
Normally, trees are the best defence against pollution; but when it's too hot outside, the trees' own self-defence mechanism may actually make things worse.
正常情況下，樹木是抵御污染的最佳衛士，但是當外界溫度過高時，樹木自身的防御機制實際上可能會令污染狀況惡化。
Trees produce natural chemicals, called isoprene and terpene, that are thought to protect their leaves from too much heat and sunlight. When the chemicals react with nitrogen oxide--found in pollution from cars--they form ozone, a much bigger health threat to humans and animals.
樹木分泌的天然化學物質異戊二烯和萜烯被認為可保護樹葉免受過多熱量和陽光的傷害。然后，當這些化學物質與氮氧化合物(存在于汽車排放的廢氣中)發生化學反應時，就會形成臭氧，這會對人類和動物的健康構成更大的威脅。
Dr Alastair Lewis and his team at Britain's York University noticed how the production of isoprene, and thus ozone, suddenly went up at high temperatures. "At 30℃, it's starting to become important. By 35℃, the emission rate has gone up by maybe an order of magnitude 10 times," Lewis told the BBC. Lewis says that isoprene and terpene were responsible for 30 percent of the ozone in the air during the hottest part of the summer.
英國約克大學的阿拉斯泰爾·劉易斯博士及其研究小組注意到異戊二烯的分泌量及隨后形成的臭氧量在高溫條件下陡然上升的過程。劉易斯對英國廣播公司的記者說：“30℃時數量開始增加。到35℃時，其排放速度則可能增加了一個數量級(10倍)。” 他還指出，在夏天最熱的時候，空氣中的臭氧有30%是由異戊二烯和萜烯生成的。
Prof.David Fowler of the Centre for Ecology and Hydrology in Edinburgh says we shouldn't blame the trees for this. "Realistically, the best way to counter this is to reduce our production of both ozone and nitrogen oxides from industrial and personal processes."
來自愛丁堡生態學與水文學中心的戴維·富勒教授認為，我們不該因此責怪樹木。他對《每日電訊報》的記者說：“現實地說，應對這一情況的最佳辦法是在我們的工業生產及個人生活中減少臭氧和氮氧化合物的排放。”