卫星图像显示冠状病毒对中国污染水平的影响

卫星图像显示冠状病毒对中国污染水平的影响

Data from NASA and the European Space Agency (ESA) pollution monitoring satellites show a sustained decrease in nitrogen dioxide (NO2) over China since the beginning of this year. According to NASA, this is “at least partly” related to the economic slowdown that has ensued from the outbreak of coronavirus.

美国国家航空航天局(NASA)和欧洲航天局(ESA)污染监测卫星的数据显示，自今年年初以来，中国上空二氧化氮(NO2)持续下降。据美国国家航空航天局称，这“至少部分”与冠状病毒爆发导致的经济放缓有关。

COVID-19, the disease caused by the SARS-CoV-2 virus, has at the time of writing infected almost 90,000 people and claimed the lives of just over 3,000. Most of the victims have been in the Hubei province in China, where the virus originated. Following the outbreak, people have been under movement restrictions across China, which at one point reportedly affected 500 million people. From transportation halting in Wuhan at the end of January, to local businesses shutting, quarantine measures are being carried out across the country to reduce the spread of the virus.

由SARS-CoV-2病毒引起的COVID-19，在撰写本文时已经感染了近9万人，夺走了3000多人的生命。大多数受害者来自中国的湖北省，那里是病毒的发源地。疫情爆发后，中国各地的人们都受到了行动限制，据报道，有5亿人受到影响。从1月底武汉的交通停运，到当地企业关闭，全国各地都在采取隔离措施，以减少病毒的传播。

Katy Pallister

Like these restrictions, NASA scientists noticed the reduction of NO2, a harmful gas emitted by motor vehicles, power plants, and industrial facilities, first became apparent near Wuhan then spread across the country.

就像这些限制一样，美国宇航局的科学家们注意到二氧化氮的减少。二氧化氮是机动车、发电厂和工业设施排放的有害气体。

“This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event,” Fei Liu, an air quality researcher at NASA’s Goddard Space Flight Center, said in a statement.

美国国家航空航天局戈达德太空飞行中心的空气质量研究员刘飞(音译)在一份声明中说:“这是我第一次看到某一特定事件在如此大的范围内发生如此剧烈的下降。”

From the information collected by the Tropospheric Monitoring Instrument on ESA’s Sentinel-5 satellite, and a related sensor, the Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite, NO2 pollution levels across China have been mapped in several periods: from January 1-20, 2020 (before quarantine), Jan 28-Feb 9, 2020 (Chinese New Year celebrations), and February 10-25, 2020 (during the quarantine).

从欧空局的Sentinel-5号卫星对流层监测仪器和一个有关传感器收集的资料中，美国国家航空航天局(NASA)的Aura卫星上的臭氧监测仪器(OMI)，中国各地的二氧化氮污染水平已经被绘制成几个时间段:从2020年1月1日至20日(检疫前)，2020年1月28日至2月9日(春节庆祝活动)，以及2020年2月10日至25日(检疫期间)。

Although there is usually a decrease in nitrogen dioxide levels during Chinese New Year celebrations, a rise has not followed the event this year, unlike in 2019. Joshua Stevens / NASA/ ESA

Past observations indicate a usual decrease around Lunar New Year celebrations, when many businesses and factories close in China and much of Asia. However, unlike in 2019 the NO2 levels did not rise again afterwards.

过去的观察显示，在农历新年前后，中国和亚洲大部分地区的许多企业和工厂都会关闭，这种情况通常会减少。然而，与2019年不同的是，此后二氧化氮含量没有再次上升。

“There is always this general slowdown around this time of the year,” Barry Lefer, an air quality scientist at NASA, explained. “Our long-term OMI data allows us to see if these amounts are abnormal and why.”

NASA的空气质量科学家巴里·莱弗解释说:“每年的这个时候，空气质量都会普遍下降。”“我们的长期OMI数据可以让我们看到这些数据是否异常，以及为什么异常。”

Using OMI’s data, researchers compared NO2 levels in 2020 with the average amounts detected at the same time of year from 2005-2019. They found that in eastern and central China the levels were between 10 to 30 percent lower than what is normally observed for this time period.

利用OMI的数据，研究人员将2020年的二氧化氮水平与2005-2019年同期的平均水平进行了比较。他们发现，在中国东部和中部地区，这一水平比正常时期低10%到30%。

This significant decrease may have other contributing factors beyond the coronavirus quarantine and Chinese New Year celebrations. Lefer noted environmental regulations that China has enforced over the past few years. Previous dramatic decreases in NO2 levels have been observed in several countries, for example during the 2008 economic recession. However, this recent reduction has been much more rapid, leading researchers to believe this event is more than a holiday effect or weather-related variation.

除了冠状病毒检疫和春节庆祝活动之外，这种显著的减少可能还有其他的影响因素。列弗提到了中国在过去几年里实施的环境法规。此前曾有几个国家观察到二氧化氮水平大幅下降，例如在2008年经济衰退期间。然而，最近这种减少的速度要快得多，这使得研究人员相信，这一事件不仅仅是假日效应或天气相关的变化。

“This year, the reduction rate is more significant than in past years and it has lasted longer,” Liu said. “I am not surprised because many cities nationwide have taken measures to minimize spread of the virus.”

“今年的降幅比往年更大，而且持续的时间更长，”刘说。“我并不感到惊讶，因为全国许多城市都采取了措施，尽量减少病毒的传播。”

This has not been the only time that environmental changes have coincided with global outbreaks of disease. A study from 2017, revealed that the 14th century Black Death outbreak occurred at the same time as the air was lead-free; the first and only time this has happened over the last two millennia. The demographic and economic collapse from the pandemic interrupted metal production, which led the researchers to believe this was at least part of the explanation for the environmental differences.

这并不是环境变化与全球疾病暴发同时发生的唯一一次。2017年的一项研究显示，14世纪黑死病爆发的同时，空气中也不含铅;这是近两千年来第一次也是唯一一次。大流行造成的人口和经济崩溃中断了金属生产，这让研究人员相信，这至少是造成环境差异的部分原因。