美國(guó)一半的空氣污染死亡與州外排放有關(guān)

美國(guó)一半的空氣污染死亡與州外排放有關(guān)

Over half the deaths due to poor air quality occurring in the U.S. are because of emissions from outside the state in which the deaths occur, according to a new study published in February 2020 in the journal Nature.

根據(jù)《自然》雜志在2020年2月發(fā)表的一項(xiàng)新研究，在美國(guó)，因空氣質(zhì)量差導(dǎo)致的死亡中，超過(guò)一半是由死亡發(fā)生地以外的州的排放造成的。

The study

研究

The tendency of air pollutants to cause death across national and international borders is well known.  Researcher Steve Barrett says, "It's been well known in Europe for over 30 years that power stations in England would create acid rain that would affect vegetation in Norway."

空氣污染物跨越國(guó)家和國(guó)際邊界造成死亡的趨勢(shì)是眾所周知的。研究員史蒂夫·巴雷特說(shuō):“30多年來(lái)，歐洲人都知道英國(guó)的發(fā)電站會(huì)產(chǎn)生酸雨，影響挪威的植被。”

On the other hand, a detailed and sequential account of this phenomenon especially with regard to human health has not yet been provided, and this motivated the current study.

另一方面，關(guān)于這一現(xiàn)象，特別是與人類健康有關(guān)的這一現(xiàn)象，尚未提供詳細(xì)和有序的描述，這促使了目前的研究。

The researchers looked at the path followed by the emission of a range of air pollutants produced by combustion in various fields, over the period 2005 to 2018. They traced these emissions in every state, from one season to the next, and from one year to the following year.

研究人員觀察了2005年至2018年期間各個(gè)領(lǐng)域燃燒產(chǎn)生的一系列空氣污染物的排放路徑。他們追蹤了每個(gè)州的排放量，從一個(gè)季節(jié)到下一個(gè)季節(jié)，從一年到第二年。

The tool

研究工具

In the past, it has been difficult to calculate the effects of air pollutants produced in one state on the residents of another. The availability of modern computers and programs has facilitated this work in the current world. This means it is now possible to track the course of emissions from and to each state with respect to the remaining states rapidly and efficiently.

過(guò)去，很難計(jì)算一個(gè)州產(chǎn)生的空氣污染物對(duì)另一個(gè)州居民的影響。現(xiàn)代計(jì)算機(jī)和程序的可獲得性促進(jìn)了當(dāng)前世界的這項(xiàng)工作。這意味著現(xiàn)在可以快速有效地跟蹤每個(gè)州相對(duì)于其余州的排放過(guò)程。

Barrett and his researchers produced such a computational tool inspired by the work of Daven Henze of the University of Colorado at Boulder. This helped them trace the effects of air pollution on health in each state. They looked at sulfur dioxide, ozone, fine particulate matter, and other pollutants from a host of emission sources at fixed intervals for each hour of each day over the whole year.

巴雷特和他的研究人員受科羅拉多大學(xué)博爾德分校的戴文·亨澤的工作啟發(fā)，開發(fā)了這樣一個(gè)計(jì)算工具。這有助于他們追蹤每個(gè)州空氣污染對(duì)健康的影響。他們觀察了全年每天每小時(shí)固定間隔的二氧化硫、臭氧、細(xì)顆粒物和來(lái)自大量排放源的其他污染物。

The sources explored include electric power plants, road transport, ships, railways, airplanes, commercial and residential emissions. The emission data was collected in 2005. 2011 and 2018.

探索的污染源包括發(fā)電廠、公路運(yùn)輸、船舶、鐵路、飛機(jī)、商業(yè)和居民排放。排放數(shù)據(jù)是在2005年、2011年和2018年收集的。

The researchers used the GEOS-Chem atmospheric chemistry model to tell them what became of these emissions at each season and each year. The path of these emissions was tracked based on the wind patterns, and the reactions of the chemicals in the pollutant to the air. They finally used a model derived from epidemiological data to measure the risk of early death due to the exposure of a population to those pollutants.

研究人員使用GEOS-Chem大氣化學(xué)模型來(lái)告訴他們這些排放在每個(gè)季節(jié)和每年都會(huì)發(fā)生什么。這些排放的路徑是根據(jù)風(fēng)型和污染物中的化學(xué)物質(zhì)對(duì)空氣的反應(yīng)來(lái)跟蹤的。他們最終使用了一個(gè)從流行病學(xué)數(shù)據(jù)中得出的模型來(lái)衡量由于人群暴露在這些污染物中而導(dǎo)致的過(guò)早死亡風(fēng)險(xiǎn)。

This model is thus a matrix with many dimensions, and it shows how the emissions from any of these sectors from any state at any time, containing any pollutant, produces an impact on the health measures of another state. Says Barrett, "We can figure out, for example, how much NOx emissions from road transportation in Arizona in July affects human health in Texas, and we can do those calculations instantly."

因此，這個(gè)模型是一個(gè)多維矩陣，它顯示了任一州在任何時(shí)間、包含任何污染物的任何這些部門的排放如何對(duì)另一個(gè)州的健康措施產(chǎn)生影響。巴雷特說(shuō)：“例如，我們可以計(jì)算出亞利桑那州7月份道路運(yùn)輸產(chǎn)生的NOx排放量對(duì)德克薩斯州人類健康的影響，我們可以立即進(jìn)行這些計(jì)算。”

The findings

結(jié)論

The study shows that of the air pollutants produced in one state, over 50 percent is carried through the air into other states. Thus, each state affects the quality of health of people living in other states and contributes to their risk of premature death. And it's not just states across the immediate border that are affected but even those farther away. Different emissions, says Barrett, travel different distances, but some effect states more than a thousand miles away from the state of origin.

研究表明，在一個(gè)州產(chǎn)生的空氣污染物中，超過(guò)50%是通過(guò)空氣進(jìn)入其他州的。因此，每個(gè)州都會(huì)影響生活在其他州的人的健康質(zhì)量，并增加他們過(guò)早死亡的風(fēng)險(xiǎn)。受影響的不只是直接邊境的州，甚至是那些更遠(yuǎn)的州。巴雷特說(shuō)，不同的排放物傳播的距離不同，但有些效應(yīng)表明距離發(fā)源地超過(guò)一千英里。

The highest risk of death due to emissions occur as a result of electric power generation. In 2005. sulfur dioxide emissions from power plant chimneys caused deaths in other states than the one in which the plant was located in 3 of 4 cases. However, since 2005 the number of early deaths due to air pollution has shown a significant downturn and was almost a third less in 2018. In concrete terms, this means about 30.000 people didn't die earlier than expected because of air pollution.

由于排放造成的死亡風(fēng)險(xiǎn)最高的原因是發(fā)電。2005年，發(fā)電廠煙囪排放的二氧化硫在電廠所在的州以外的其他州造成了4例死亡中的3例。然而，自2005年以來(lái)，因空氣污染而過(guò)早死亡的人數(shù)出現(xiàn)了顯著下降，2018年幾乎減少了三分之一。具體地說(shuō)，這意味著大約有3萬(wàn)人沒(méi)有比預(yù)期更早地死于空氣污染。

Moreover, the percentage of deaths due to out-of-state emissions is also declining, from about 53 percent in 2005 to about 41 percent in 2018. The reason may be stricter regulation of emissions from electric power plants. For instance, the Clean Air Act is a regulation passed by the Environmental Protection Agency (EPA), which is a chief contributor to reducing emissions from this sector, among other laws. Barrett says, "Regulators in the U.S. have done a pretty good job of hitting the most important thing first, which is power generation, by reducing sulfur dioxide emissions drastically, and there's been a huge improvement, as we see in the results."

此外，因州外排放造成的死亡比例也在下降，從2005年的約53%下降到2018年的約41%。原因可能是對(duì)發(fā)電廠排放的監(jiān)管更加嚴(yán)格。例如，《清潔空氣法》是美國(guó)環(huán)境保護(hù)局通過(guò)的一項(xiàng)法規(guī)，它是減少該部門排放的主要貢獻(xiàn)者，以及其他法律。巴雷特說(shuō)，“美國(guó)的監(jiān)管機(jī)構(gòu)通過(guò)大幅減少二氧化硫排放，在首先打擊最重要的事情-發(fā)電方面做得相當(dāng)好，正如我們?cè)诮Y(jié)果中看到的那樣，已經(jīng)有了巨大的改善。”

However, emissions from other sources are now on the rise, wafting across state lines to cause deaths in other locations. According to Barrett, vehicles, industrial emissions, and residential emissions are now areas of concern.

然而，來(lái)自其他來(lái)源的排放現(xiàn)在正在上升，飄過(guò)州界在其他地方造成死亡。根據(jù)巴雷特的說(shuō)法，車輛、工業(yè)排放和居民排放現(xiàn)在是令人擔(dān)憂的領(lǐng)域。

The implications

影響

Barrett says their team has set up a massive database for use by people concerned with public health. He concludes, "We think there are a lot of things that policymakers can dig into, to chart a path to saving the most lives."

巴雷特說(shuō)，他們的團(tuán)隊(duì)已經(jīng)建立了一個(gè)龐大的數(shù)據(jù)庫(kù)，供關(guān)注公共衛(wèi)生的人使用。他總結(jié)道，“我們認(rèn)為政策制定者可以深入研究很多東西，以規(guī)劃出一條拯救最多生命的道路。”