研究稱空氣污染可能損害語言和數(shù)學能力

HONG KONG — A large study in China suggests a link between air pollution and negative effects on people’s language and math skills.

香港——中國的一項大型研究表明，在空氣污染和對人的語言和數(shù)學能力的負面影響之間存在著聯(lián)系。

The link between pollution and respiratory diseases is well known, and most experts now believe that small particulates may also raise the risk for strokes and heart attacks. Whether this form of air pollution impairs cognition is not yet certain, but several studies have hinted at a connection.

污染和呼吸系統(tǒng)疾病之間的聯(lián)系是眾所周知的，此外大多數(shù)專家現(xiàn)在相信，微小顆粒還會增加中風和心臟病的風險。這種形式的空氣污染是否會損害認知還不確定，但是幾項研究顯示可能存在這種聯(lián)系。

The latest study, by researchers based in China and the United States, analyzed how long-term exposure to air pollution affected performance on nationwide math and word-recognition tests by more than 25,000 people across 162 Chinese counties. It was published on Monday in Proceedings of the National Academy of Sciences.

由在中國和美國的研究者進行的這項最新研究，分析了長期暴露在空氣污染中對中國162個縣超過25000人的全國數(shù)學和詞匯識別測試成績的影響。《美國國家科學院院刊》(Proceedings of the National Academy of Sciences)周一發(fā)表了這項研究。

The authors based their findings on models they built that combined weather and pollution data from specific locations in China where people had taken nationwide tests in 2010 and 2014, as well as the test scores themselves. Their analysis tried to document how short- and long-term pollution exposure might have affected the scores — and, by extension, the test-takers’ brains.

研究作者的發(fā)現(xiàn)基于他們所建的模型，這些模型結(jié)合了來自中國特定地點的氣候和污染數(shù)據(jù)，受試者于2010年和2014年在這些地方接受了全國測試，模型還采用了這些測試的分數(shù)。他們的分析試圖記錄短期和長期暴露在空氣污染中可能會如何影響這些分數(shù)——以及，可能如何進一步影響受試者的大腦。

The authors found that the cognitive impact of cumulative exposure among the test takers was especially pronounced among older men, and that the results were troubling in part because cognitive decline and impairment are risk factors for Alzheimer’s disease and other forms of dementia.

作者發(fā)現(xiàn)，累積的污染暴露對受試者認知的影響，在年長男性中最為明顯，這些結(jié)果讓人不安，部分是因為認知衰退和損傷是阿茲海默癥和其他形式的失智癥的風險因素。

The study “further amplifies the need to tackle air pollution now to protect the health of particularly the young and elderly populations,” Heather Adair-Rohani, a technical officer for public health and environment at the World Health Organization in Geneva, which was not involved in the study, said in an email.

這項研究“進一步強調(diào)，立即著手處理空氣污染問題，對保護年幼和年長人口健康格外有必要”，日內(nèi)瓦世界衛(wèi)生組織公共衛(wèi)生與環(huán)境技術(shù)官員希瑟·阿代爾-羅哈尼(Heather Adair-Rohani)在一封電子郵件中說，他沒有參與這項研究。

Atmospheric pollution has long been recognized as a significant threat to global public health.

大氣污染一直以來被認為是對全球公共健康的嚴重威脅。

In 2016, the W.H.O. reported that 92 percent of people worldwide breathe what it classified as unhealthy air. It defined that air as having concentrations of fine particulate matter, known as PM2.5, above 10 micrograms per cubic meter, or 35.3 cubic feet.

2016年，世界衛(wèi)生組織報告稱，全球92%的人呼吸著該組織認為不健康的空氣。它對不健康的定義是空氣中的微小顆粒——即PM2.5——濃度高于每立方米10微克。

The agency said in May that outdoor air pollution caused approximately 4.2 million premature deaths worldwide in 2016, more than a million of them in China, and that short- and long-term exposure increased the risk of stroke, heart disease, lung cancer and chronic and acute respiratory diseases.

該組織在5月表示，室外空氣污染在2016年造成了大約420萬例過早死亡，其中超過一百萬發(fā)生在中國，短期和長期的污染暴露加劇了中風、心臟病、肺癌和慢性以及急性呼吸系統(tǒng)疾病的風險。

This month a study in the journal Environmental Science & Technology Letters calculated that air pollution was reducing average life expectancies; the exact risk depended on location — around nine months in Russia, for example, or 1.9 years in Egypt.

根據(jù)本月《環(huán)境科學與技術(shù)通訊》(Environmental Science & Technology Letters)一項研究的估算，空氣污染正在減少平均預(yù)期壽命;具體的風險取決于地理位置——例如，在俄羅斯約為9個月，在埃及約為1.9年。

But few epidemiological studies have analyzed associations between air pollution and cognition in older adults, a team of researchers from France and Britain wrote in a 2014 study in the journal Epidemiology. Their study found that traffic-related pollution in greater London was associated with declining cognitive functions over time among study participants, who had an average age of 66.

但是，法國和英國的一組研究人員2014年在《流行病學》(Epidemiology)期刊上寫道，很少有流行病學研究分析空氣污染與老年人認知之間的聯(lián)系。他們的研究發(fā)現(xiàn)，在大倫敦地區(qū)，交通相關(guān)污染與受試者認知機能隨時間推移而下降相關(guān)，研究參與者平均年齡為66歲。

In China, which already has the world’s largest population of people with dementia, the number is expected to rise to 75.6 million by 2030, up from about 44.4 million in 2013, according to a report that year by Alzheimer’s Disease International, a nonprofit based in Chicago.

根據(jù)位于芝加哥的非營利組織阿爾茨海默病國際組織(Alzheimer's Disease International)今年的一份報告顯示，中國擁有世界上最多的失智癥患者，預(yù)計到2030年，將從2013年的4440萬人增加到7560萬人。

The new study’s findings “imply that the indirect effect on social welfare could be much larger than previously thought,” the authors wrote. “A narrow focus on the negative effect on health may underestimate the total cost of air pollution.”

這項新研究的結(jié)果“意味著對社會福利的間接影響可能比以前認為的要大得多，”作者寫道。“對健康的負面影響關(guān)注過于狹隘，可能會低估空氣污染的總成本。”

The study used test scores from the 2010 and 2014 editions of China Family Panel Studies, an interview-based exam given nationwide, as well as air-quality data from readings of three types of pollutants: sulfur dioxide, nitrogen dioxide and particulate matter that is between 2.5 and 10 micrometers in diameter, called PM10.

該研究使用了2010年和2014年中國家庭追蹤調(diào)查(China Family Panel Studies)的測試結(jié)果，這是一項全國范圍內(nèi)的研究，包括基于面試的考試結(jié)果，以及三種污染物的空氣質(zhì)量數(shù)據(jù)：二氧化硫、二氧化氮和直徑在2.5到10微米之間，被稱為PM10的顆粒物質(zhì)。

“Essentially, we compare the same person in two time periods,” said Zhang Xin, the study’s lead author and a pollution expert at Bejing Normal University, referring to the study’s methodology. “The major variation stems from exposure to local air pollution at the date of interview, which is largely random.”

“基本上，我們在兩個不同時期比較同一個人，”該研究的主要作者、北京師范大學污染專家張欣提到該研究所采取的方法。“主要變量源于采訪當天的當?shù)乜諝馕廴?，在很大程度上是隨機的。”

The study found that “accumulative exposure” had a pronounced impact on verbal test scores — especially for older, less-educated men — and that cutting the local concentration of PM10 to levels that meet United States Environmental Protection Agency air quality standards would move people up from the median, or 50th percentile, to the 58th percentile on math test scores and the 63rd percentile on verbal scores.

該研究發(fā)現(xiàn)，“累積暴露”對口頭測試結(jié)果有顯著影響——特別是對于年齡較大、受教育程度較低的男性——并且，如果當?shù)豍M10的濃度降低到符合美國環(huán)境保護局(United States Environmental Protection Agency)空氣質(zhì)量標準的水平，會使人們的數(shù)學考試成績從中位值，或第50個百分位，上升到第58個百分位;并令口頭考試成績上升到第63個百分位。

He Guojun, an economist at the Hong Kong University of Science and Technology who studies pollution in China, said that he hoped the new study would be the first of many to examine apparent links between pollution and cognition in China. “The paper is quite solid, both in terms of data and methodology and results,” said Dr. He, who was not involved in the study.

研究中國污染問題的香港科技大學經(jīng)濟學家何國俊表示，他希望這項新研究能夠帶動對中國污染與認知之間明顯聯(lián)系的更多研究。“在數(shù)據(jù)、方法和結(jié)果方面，這篇論文很扎實，”沒有參與這項研究的何國俊說。

The research tried to minimize the impact of other variables besides pollution. For example, it excluded test takers who migrated across counties between 2010 and 2014, and others who worked in mining, smelting, wood processing and other “polluted occupations.”

該研究試圖將污染以外的其他變量的影響降至最低。例如，它排除了2010年至2014年間跨縣遷徙的測試者，以及從事采礦、冶煉、木材加工和其他“污染職業(yè)”的人。

However, Dr. He said, measuring long-term effects of pollution exposure can be difficult, in part because individual exposure depends on so many factors — including, for example, whether a person uses air filters at home.

然而，何國俊說，測試污染暴露的長期影響可能很困難，部分原因是個人暴露取決于很多因素，例如是否在家中使用空氣過濾器。

In another critique, Rajasekhar Balasubramanian, an air quality expert at the National University of Singapore, noted that while the study’s authors speculate that continued exposure to pollution can alter brain chemistry, they offered no clinical proof. (The authors agreed, writing that the hypothesis should be explored further.)

在另一項批評中，新加坡國立大學的空氣質(zhì)量專家拉賈塞卡·巴拉蘇布拉馬尼安(Rajasekhar Balasubramanian)指出，雖然該研究的作者推測，持續(xù)暴露于污染之下會改變大腦化學物質(zhì)，但他們沒有提供臨床證據(jù)。(論文作者表示同意，并寫道應(yīng)該進一步探討該假設(shè)。)

But Dr. Balasubramanian said the study was useful in part because, while the effects of pollution on children’s cognition had been documented by epidemiologists, this was the first to focus on such risks to China’s older people. He said similar research was now needed in other countries. 但巴拉蘇布拉馬尼安表示，這項研究之所以有用，是因為雖然流行病學家已經(jīng)記錄了污染對兒童認知的影響，但這是第一次關(guān)注污染對中國老年人的風險。他說其他國家現(xiàn)在需要進行類似的研究。

“The outcome of such studies would provide a sound scientific basis for tightening air quality standards to curtail air pollution and protect public health in both developing and developed countries,” Dr. Balasubramanian, who was not involved in the study, said in an emailed statement.

“這類研究的結(jié)果將為提高空氣質(zhì)量標準提供合理的科學依據(jù)，以減少發(fā)展中國家和發(fā)達國家的空氣污染，并保護公眾健康，”未參與該研究的巴拉蘇布拉馬尼安在一份電子郵件聲明中表示 。

As public outrage has grown in China over smog and respiratory illnesses related to it, officials have in recent years closed hundreds of coal-fired power plants, imposed limits on driving and residential coal burning, and sent teams of police officers to inspect factories.

由于中國公眾對霧霾和與之相關(guān)的呼吸系統(tǒng)疾病的憤怒日益增加，近年來，官員關(guān)閉了數(shù)百座燃煤電廠，限制了車輛和住宅燃煤，并派出大批警察到工廠進行檢查。

But China’s carbon dioxide emissions increased last year, and even though the country is on its way to meeting its major climate change goals, many of its cities still have dangerously high levels of outdoor air pollution.

但去年中國的二氧化碳排放量有所增加，盡管該國正在實現(xiàn)其主要的氣候變化目標，許多城市仍然存在危險的重度戶外空氣污染。

In one sign of the problems, a study published in April found that about 142 million people, or just over half the population surveyed in 155 Chinese cities, were exposed in 2014 to average annual “multicontaminant concentrations” that were above the World Health Organization’s limits. The study said that eastern China and megacities were worst affected.

4月發(fā)表的一項研究揭示了這類問題的其中一個表現(xiàn)，研究發(fā)現(xiàn)，2014年大約有1.42億人，或155個接受調(diào)查的中國城市的一半以上人口，暴露在高于世界衛(wèi)生組織規(guī)定年平均濃度的多污染物中。該研究稱，中國東部和特大城市受影響最嚴重。