科学网今日新闻“美宇航局卫星拍到中国内陆严重雾霾分布图”的中文说明，应当是从英文新闻稿翻译过来的。可能英文新闻稿编辑的文字就有增删，造成重要信息缺失。

查了美国宇航局NASA新闻原稿：

http://earthobservatory.nasa.gov/IOTD/view.php?id=82535

下面翻译的中文中，用蓝色标出的比较重要，用红色标出的，对认识这次雾霾较重的原因及其发展是重要信息。

但是，中文新闻稿中关于烟雾的来源，以及造成雾霾的原因，则是编译的媒体工作者写的，不在NASA新闻原稿中。

Smog Shrouds Eastern China

December 10, 2013

China suffered another severe bout of air pollution in December 2013. When the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired this image on December 7, 2013, thick haze stretched from Beijing to Shanghai, a distance of about 1,200 kilometers (750 miles). For comparison, that is about the distance between Boston, Massachusetts, and Raleigh, North Carolina. The brightest areas are clouds or fog. Polluted air appears gray. While northeastern China often faces outbreaks of extreme smog, it is less common for pollution to spread so far south.

中国在2013年12月经受了又一次严重空气污染事件。美国宇航局的Terra得到12月7日卫星遥感（MODIS）图观察到厚重的霾从北京伸展到上海，约1200公里（750英哩），相当于从马萨诸塞州的波斯顿到北卡罗莱纳的罗利。图上亮白色的是云或雾，污染空气显示为灰色。中国的东北部常见严重烟雾，象这次污染伸展到如此远的南部较为少见。

“The fog has a smooth surface on the top, which distinguishes it from mid- and high-level clouds that are more textured and have distinct shadows on their edge,” explained Rudolf Husar, director of the Center for Air Pollution Impact and Trend Analysis at Washington University. “If there is a significant haze layer on top of the fog, it appears brownish. In this case, most of the fog over eastern China is free of elevated haze, and most of the pollution is trapped in the shallow winter boundary layer of a few hundred meters.”

华盛顿大学空气污染影响和趋势分析中心主任Rudolf Husar 说：“雾区的顶部表面平滑，这可以和中层和高层云区别开来，云的形态比较粗糙而且边部有明显阴影。”“如果在雾的上面有一层霾，就会显示棕色。这次中国东部地区的雾大部分和霾无关，大部分污染被约束在只有几百米厚的冬季边界层内。”

On the day this natural-color image was acquired by Terra, ground-based sensors at U.S. embassies in Beijing and Shanghai reported PM_2.5 measurements as high as 480 and 355 micrograms per cubic meter of air respectively. The World Health Organization considers PM_2.5 levels to be safe when they are below 25.

获得Terra遥感图的当日，北京和上海观测的PM2.5浓度分别高达480和355微克/立方米，世界卫生组织的安全标准仅为25微克/立方米。

Fine, airborne particulate matter (PM) smaller than 2.5 microns (about one thirtieth the width of a human hair) is considered dangerous because it is small enough to enter the passages of the human lungs. Most PM2.5 aerosol particles come from the burning of fossil fuels and of biomass (wood fires and agricultural burning).

因为细微可以进入人类肺部，细颗粒物PM2.5（约1/15人类头发粗细）被认为最危及健康。大部分PM2.5气溶胶源自化石燃料和生物质的燃烧（树木和农业烧荒）。

At the time of the satellite image, the air quality index (AQI) reached 487 in Beijing and 404 in Shanghai. An AQI above 300 is considered hazardous to all humans, not just those with heart or lung ailments. AQI below 50 is considered good.

拍摄遥感图时，空气质量指数在北京市487，上海404。AQI超过300时被认为严重污染，对所有人群都有危害，而不只是影响有肺部疾患的病人。AQI低于50时，认为空气质量为优。

In some cities, authorities ordered school children to stay indoors, pulled government vehicles off the road, and halted construction in an attempt to reduce the smog, according to news reports.

新闻报道说，有些城市要求学校学生留在室内，停开政府部门的汽车，停止建筑工程，意图减轻烟雾。

References

Associated Press, via The Washington Post (2013, December 6) Smog at Extremely Hazardous levels in Shanghai. Accessed December 9, 2013.

Bloomberg News (2013, December 9) Shanghai Tells Children to Stay Inside for Seventh Day on Smog. Accessed December 9, 2013.

The New York Times (2013, December 5) Air Pollution Shrouds Eastern China. Accessed Accessed December 9, 2013.

U.S. Department of State (2013, December 9) U.S. Consulate Shanghai Air Quality Monitor. Accessed December 9, 2013.

U.S. Department of State (2013, December 9) U.S Embassy Beijing Air Quality Monitor. Accessed December 9, 2013.

Voice of America (2013, December 6) Flights Delayed as Air Pollution Hits Record in Shanghai. Accessed December 9, 2013.

Xinhua (2013, December 9) Cities hit hard by smog. Accessed December 9, 2013.

NASA image courtesy Jeff Schmaltz, LANCE MODIS Rapid Response. Caption by Adam Voiland.

其实中国研究人员也用Terra MODIS真彩色图像进行分析，甚至有逐日发展过程。推荐李芳军博主

2013-12-8 博文：“看图说 ‘华-北、西、南、东、中’ 地区12月第1周（01-07）雾霾”

http://blog.sciencenet.cn/blog-427149-748130.html 

2013-12-10 博文：“看图说-‘像云像雾又像霾’-如何在真彩色遥感图像上识别”

http://bbs.sciencenet.cn/blog-427149-748645.html