The goal is to learn how to write better.

分析的目的是为了提高科技英语写作水平(不是针对作者)。

Green highlight is used to show good writing.

好好学习：用绿色标出。

Yellow means "questionable."

敢于提问：用黄色标出。

https://www.nature.com/articles/s41561-019-0406-7?utm_source=ngeo_etoc&utm_medium=email&utm_campaign=toc_41561_12_7&utm_content=20190627&WT.ec_id=NGEO-201907&sap-outbound-id=7488AC1210240A5F2BF7B1DA45FB1CDE83D17CE9&mkt-key=005056B0331B1EE889D67AD104987739

China’s rigorous air-pollution control has greatly reduced the levels of fine particles in the atmosphere. Further progress for air quality more broadly will rely on fully accounting for complex chemical reactions between pollutants.

This yearthe United Nation’s World Environment Day on 5 June 2019 shone a spotlight on air pollution. The official celebrations took place in China, a country whose choking air has frequently made international headlines. This year, the outlook is more optimistic. China’s Ministry of Ecology and Environment (https://go.nature.com/2xaWNEI) reported a significant decline in the annual-mean level of fine particulates, known as PM_2.5:concentrations fell by 42% between 2013 and 2018 across 74 large cities in China. A roundtable discussion between scientists specializing in atmospheric chemistry, economy and environmental health was arranged by Nature Geoscience in Beijing on 6 June 2019. It concluded that in order to make further progress, the focus of environmental controls in China must be broadened to other pollutants and their precursors.

The rapid improvement in air quality in China has been driven by strong political commitment. After a series of extreme pollution events in 2013, the central government made a firm promise to fight air pollution. Over the past six years, this commitment has been translated into concrete measures, such as enhancing end-of-pipe control and optimizing industrial structure, and the success is now evident. However, it will be increasingly difficult for China to maintain the same rate of air-quality improvement. And reducing concentrations of air pollutants to the levels recommended by the World Health Organization is the next — and more difficult — challenge for China.

China’s air pollution is different from the mix found in Europe and North America: it is characterized by enormous levels of anthropogenic emissions and highly complex chemical reactions in the atmosphere. The heavy burden of pollution in China is deeply rooted in the country’s emission-intensive industries and coal-dominated energy structure. And extraordinarily rapid economic development, with a concurrent boom in industry and urbanization, has led to a coincidence of pollution sources that have been characteristic of different phases of socioeconomic development in Europe and North America. As a result, anthropogenic sources of emissions are complex and the amounts of pollutants emitted, such as sulfur dioxide (SO₂), nitrogen oxides (NO_x) and carbon monoxide, are many times higher than those currently emitted in Europe and North America. Once released, those pollutants can be involved in complex chains of chemical reactions in the atmosphere that make it difficult to control secondary pollutants.

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如果你想提高科技英语写作能力，请跟我来...

http://blog.sciencenet.cn/blog-306792-1146690.html