英國廣播公司文章：研究表明，空氣污染可能損害認知能力

來自專欄通過新聞報紙學英語

英國廣播公司文章：研究表明，空氣污染可能損害認知能力（Air pollution may harm cognitive intelligence, study says http://www.bbc.co.uk/news/health-45326598）譯述，英文附後。

在中國做的一項新的研究表明，慢性接觸污染的空氣可能與認知能力有關。

研究人員認為，負面影響會隨著年齡增長而增長，並且會影響受教育程度最低的男性。

四年多來，這項美中聯合研究對中國約2萬人的數學和語言技能進行了監測。

研究人員認為，這些結果具有全球意義，世界上80％以上的城市人口呼吸著不安全的、污染的空氣。

然而，在確定污染與較低測試分數之間的相關時，該研究並未證明因果關係。

研究人員來自北京大學和耶魯大學。研究測量了受試生活環境中的二氧化硫、二氧化氮和直徑小於10微米的微粒。目前尚不清楚這三種污染物中每一種的影響程度有多大。

研究中不包括一氧化碳，臭氧和較大顆粒。

據世界衛生組織稱，空氣污染被描述為無形的殺手，每年造成全球約700萬人過早死亡。

「我們提供的證據表明，隨著人們年齡的增長，空氣污染對言語測試的影響變得更加明顯，特別是對於男性和受教育程度較低的人，」該研究周一發表在《美國國家科學院院刊》上。

該研究表明，污染還會增加阿爾茨海默氏症和其他形式痴獃等退行性疾病的風險。

「我們的樣本使我們能夠檢查空氣污染隨著人們年齡增長產生的影響。我們縱跨整個生命歷程中的研究結果是首創的，」耶魯大學公共衛生學院的共同作者之一的陳琛告訴BBC。

在這項研究中，研究人員測試了2010年至2014年期間10歲及以上的男性和女性，包括24個標準化數學問題和34個單詞識別問題。

以往的研究發現空氣污染對學生的認知能力有負面影響。

「這項最新研究與之前的研究相符，」香港理工學院的Derrick Ho說道，他致力於研究霧霾等極端天氣事件對健康的影響。

他在接受英國廣播公司採訪時說：「本文新的內容是對中國情景的關注，與許多其他研究的相比，這是一項非常詳細的研究。」 「此外，按性別和年齡維度做出區分也是首創。」

戶外工作

許多污染物被認為以各種方式直接影響大腦化學過程。例如，顆粒物質可以通過小通道攜帶毒素直接進入大腦。

一些污染物也會產生心理影響，增加抑鬱的風險。

世界各地的空氣污染統計（數據資料來源：世界衛生組織）：

每年約有700萬人因接觸受污染的空氣而死亡

2016年全球空氣污染造成420萬人死亡

全球91％的人口居住在空氣質量超過世界衛生組織制定的標準的地方

有14個印度城市屬於世界上污染最嚴重的20個城市，北部城市坎普爾名列榜首

世界上有十??分之九的人呼吸污染的空氣

研究人員認為，受教育程度較低的老年男性受長期接觸空氣污染影響最嚴重的原因之一是因為這些受試經常從事戶外手工工作。

該研究得出結論：「我們關於空氣污染對認知破壞性影響的研究結果，特別是對逐漸衰老的大腦的影響，表明，空氣污染對人們福祉的間接影響可能比以前認為的要大得多。」

「對於老年人（年齡在55-65歲或65歲以上），由於長期累積暴露，影響可能很難緩解，」有位習先生說。

「這非常令人擔憂，因為我們都知道人們往往不得不在老年時做出重要的財務決策，比如什麼時候應該退休，哪個健康保險計劃更好。」

該研究表明，雖然研究結果是針對中國的，但它可以對其他嚴重空氣污染的發展中國家有所啟示。

作者指出，低收入和中等收入國家中98％超過10萬人口的城市未能達到世衛組織的空氣質量標準。

Air pollution may harm cognitive intelligence, study says

BBC Health, Aug. 29, 2018

Chronic exposure to air pollution could be linked to cognitive performance, a new study in China suggests.

Researchers believe that the negative impact increases with age, and affects men with less education the worst.

Over four years, the maths and verbal skills of some 20,000 people in China were monitored by the US-Chinese study.

Researchers believe the results have global relevance, with more than 80% of the worlds urban population breathing unsafe levels of air pollution.

However, while establishing a link between pollution and lower test scores, the study did not prove cause and effect.

The study - which includes researchers from Beijings Peking University and Yale University in the US - was based on measurements of sulphur dioxide, nitrogen dioxide and particulates smaller than 10 micrometres in diameter where participants lived. It is not clear how much each of these three pollutants is to blame.

Carbon monoxide, ozone and larger particulates were not included in the study.

Described as an invisible killer, air pollution causes an estimated seven million premature deaths a year worldwide, according to the World Health Organization.

"We provide evidence that the effect of air pollution on verbal tests becomes more pronounced as people age, especially for men and the less educated," the study published on Monday in the Proceedings of the National Academy of Sciences said.

Pollution also increases the risk of degenerative diseases such as Alzheimers and other forms of dementia, the study suggests.

"Our sample enables us to examine the impact of air pollution as people age. So our results across the life course are quite new," one of the co-authors, Xi Chen of the Yale School of Public Health, told the BBC.

In this study, researchers tested people of both sexes aged 10 and above between 2010 and 2014, with 24 standardised maths questions and 34 word-recognition questions.

Previous studies found air pollution had a negative impact on students cognitive abilities.

"This latest study matches with previous research," says Derrick Ho of Hong Kong Polytechnic who has worked on the health effects of extreme weather events like haze.

"Whats new in this paper is the focus on the China scenario and the fact that its a very detailed study compared to many other ones," he told the BBC. "Also the differentiation between gender and age in this detail is new."

Outdoor jobs

Many pollutants are thought to directly affect brain chemistry in a variety of ways - for instance, particulate matter can carry toxins through small passageways and directly enter the brain.

Some pollutants can also have a psychological impact, increasing the risk of depression.

Air pollution around the world - the stats

About seven million people die every year from exposure to polluted air

Air pollution caused 4.2 million deaths globally in 2016

91% of the worlds population lives in places where air quality exceeds WHO guideline limits

14 Indian cities are among the worlds 20 most polluted, with the northern city of Kanpur topping the list

Nine out of 10 people in the world breathe polluted air

Source: World Health Organization

One of the reasons the researchers suggest older men with less education were worst affected by chronic exposure to air pollution is because those subjects often work outdoor manual jobs.

"Our findings about the damaging effect of air pollution on cognition," the study concludes, "particularly on the aging brain, imply that the indirect effect on social welfare could be much larger than previously thought."

"For older persons (in our study those age 55-65 or 65+) the effects can be very difficult to mitigate given the long term cumulative exposure," Mr Xi says.

"This is very worrisome as we all know that people often have to make important financial decisions in old age, such as when we should retire, which health insurance plan is better."

The study suggests that while the research findings are specific to China, it can shed light on other developing countries with severe air pollution.

The authors point to the 98% of cities with more than 100,000 people in low- and middle-income countries that fail to meet WHO air quality guidelines.

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