Global Warming Causes Earlier Pollen Season
From VOA Learning English, this is the Health & Lifestyle report.
When Dr. Stanley Fineman started as an allergist, he told patients to start taking medications and prepare for pollen season in the middle of March.
That was about 40 years ago. Today, he tells them to start around the middle of February.
Since 1990, pollen season across the United States and Canada has been starting earlier, about 20 days earlier. And pollen loads, the amount of pollen released by plants, are 21 percent higher.
The main reason for this, a new study found, is global warming.
Other studies have shown North America's allergy season getting longer and worse. But this one, published in the Proceedings of the National Academies of Sciences, has the most complete information coming from 60 reporting stations. It is also the first study to make scientific connections between an earlier and more intense pollen season with human-caused climate change.
The study says the warmer the Earth gets, the earlier spring starts for animals and plants, especially plants that release pollen. Additionally, trees and plants produce more pollen when they get carbon dioxide.
Bill Anderegg is the lead writer of the study. He said, "climate change is here and it's in every breath we take." The University of Utah scientist told the Associated Press (AP), "This is clearly warming temperatures and more carbon dioxide putting more pollen in the air."
Scientists are not sure why trees are giving off the allergy-causing particles earlier than grasses. But Anderegg said just look at cherry blossoms opening earlier in Japan and Washington, D.C. as an example.
Scientists involved in the study also considered that parks and cities were getting greener. They also compared what is happening now in our environment to computer models of an Earth without human-caused warming and rising carbon dioxide in the air.
Since 1990, about half of the earlier pollen season was linked to climate change — mostly from warmer temperatures. But plant-feeding carbon dioxide, Anderegg said, played a part.
However, since the 2000s, he said, about 65 percent of early pollen seasons can be blamed on warming. And about 8 percent of the increased pollen load can be blamed on climate change.
Chris Downs of St. Louis, Missouri does not need a study to show that he already has problems with breathing, headaches, and red itchy eyes. His allergies usually hit in March. But the last two years, they came in early February, along with blooms of trees and flowers.
"As a kid I never saw anything start blooming in February," Downs said, "Now I see a handful of years like that."
For Amir Sapkota, this is not just a matter of sneezing and watery eyes. There are more serious health concerns. The University of Maryland scientist said the pollen is a risk for other diseases including asthma.
She told the AP, "Asthma costs the U.S. economy an estimated $80 billion per year in terms of treatment and loss of productivity." So, a longer pollen season is a threat to both "individuals suffering from allergies as well as the U.S. economy."
There are other problems as well. Sapkota recently found a connection between earlier spring allergies and an increased risk in asthma hospitalizations. Another study, Anderegg said, found that students do worse on tests because of pollen levels.
The U.S. Centers for Disease Control and Prevention has some advice on how to protect yourself against pollen:
Take your allergy and/or asthma medications as advised by your health care provider.
Do not touch your eyes while you are outside.
Wash after being outside to remove pollen from your skin and hair.
Change your clothes after being outdoors.
Keep windows closed during pollen season.
And that's the Health & Lifestyle report. I'm Anna Matteo.
1. start as 以…起步（或起家）；起初是；
She started as a secretary but ended up running the department.
2. give off 释放，放出，发出（气体、热量、气味等）；
Many household products give off noxious fumes.
3. in terms of 在…方面；从…角度看；根据…来说；
The data is limited in terms of both quality and quantity.
4. remove from 去除，排除；
Filters do not remove all contaminants from water.
那是大约40年前的事情 。今天，他告诉人们从二月中旬开始做准备 。
自1990年以来，美国和加拿大的花粉季开始得更早，大约提前了20天 。植物释放的花粉量增加了21% 。
其他研究表明，北美的过敏季越来越长，也越来越严重 。而这篇发表在《美国国家科学院院刊》上的文章，拥有来自60个报告站的最完整信息 。这也是首个将更早、更强烈的花粉季与人类所引起气候变化联系起来的科学研究 。
研究表明，地球温度越高，动植物春天的到来就越早，尤其是释放花粉的植物 。此外，树木和植物在吸收二氧化碳时会产生更多的花粉 。
比尔·安德雷格是这项研究的主要作者 。他表示，“气候变化已经出现，我们每一口呼吸都在变化 。”这位犹他大学的科学家对美联社（简称AP）表示，“显然，气温升高，二氧化碳增加，空气中的花粉量也在增加 。”
科学家尚不清楚为何树木比草更早释放出引起过敏的微粒 。但安德雷格表示，日本和华盛顿特区早些时候开放的樱花就是例证 。
参与这项研究的科学家还认为，公园和城市的“绿色”变得越来越多 。他们还将我们环境中正在发生的情况与没有人为变暖、空气中二氧化碳浓度也未上升的地球计算机模型进行了比较 。
自1990年以来，约一半的花粉季提前与气候变化有关，主要原因是气温升高 。但安德雷格表示，以植物为食的二氧化碳也起了一定作用 。
然而，他表示，自21世纪以来，大约65%的花粉季提前可以归咎于气候变暖 。大约8%的花粉量增加可归咎于气候变化 。
密苏里州圣路易斯的克里斯·唐斯不需要研究来证明他已经有呼吸、头痛和眼睛发红发痒的问题 。他的过敏症通常在三月份发作 。但在过去两年，这些症状在2月初就开始出现，正是树木生长、鲜花盛开的时候 。
对阿米尔·萨普科塔来说，这不仅仅是打喷嚏和流眼泪的问题 。还可能引起更严重的健康问题 。这名来自马里兰大学的科学家表示，花粉有可能引发包括哮喘在内的其他疾病 。
她对美联社表示，“哮喘每年给美国经济带来800亿美元的治疗费用和生产力损失 。”因此，花粉季的延长对“过敏患者和美国经济都是威胁 。”
还有其他问题 。萨普科塔最近发现，早春过敏与哮喘住院风险增加之间存在联系 。安德雷格表示，另一项研究发现，学生在测试中表现较差是因为花粉量过高 。
以上是健康生活报道 。我是安娜·马迪奥 。