Only 9 percent of people in China live in an environment that meets the national air quality standards, according to a scientific journal article.

根据一篇科学期刊文章表示，只有9％的中国人生活在符合国家空气质量标准的环境下。

The article, published in a scientific journal of the Nature Publishing Group Scientific Reports on October 15, and authored by two experts from the Nanjing University of Information Science and Technology, said that among the 190 cities they monitored, only 25 met national air quality standards.

该文10月15日发表于自然出版集团科研报告这一科学期刊，由南京信息科技大学的两位专家撰写，文章指出，在他们监测的190个城市中，只有25个达到国家空气质量标准。

Analysts¹ said they believe that although China has made headway in recent years in protecting the environment, there's a long way to go.

分析专家表示，中国虽然近年来在保护环境方面取得了显著进展，但现实情况仍是任重而道远。

The two authors analyzed² the density³ of PM2.5 - airborne particles smaller than 2.5 microns in diameter and a major air pollutant⁴ - collected from the latest air quality monitoring network of China's Ministry⁵ of Environmental Protection in 190 major cities from April 2014 to April 2015.

两位作者分析了PM2.5浓度，PM2.5是指空气中直径小于2.5微米的颗粒，是主要的空气污染物，数据采集自中国环保部在190个主要城市从2014年4月至2015年4月的最新空气质量监测网。

The article said that the population-weighted exposure to PM2.5 is 61 micrograms per cubic meter, three times higher than the global level.

文章指出，人口增加造成PM2.5为每立方米61微克，高于全球水平的三倍。

It also concluded that the PM2.5 density is generally higher in northern China than in the south, and that the density is higher in inland than coastal⁶ cities.

文章还总结到，PM2.5浓度总体来说，北方高于南方，内陆高于沿海。

"There is less rainfall in northern China and emissions⁷ from coal-fired heating plants in winter have led to a high density in these areas," Qi Zhiqiang, a research fellow from the Nanjing University-ISC Environmental Health and Safety Academy, told the Global Times.

“中国北方降雨较少，冬季燃煤供热厂的废弃排放导致了在这些区域的高密度” ，齐志强，南京大学ISC环境健康与安全研究院的研究员，告诉环球时报。

Qi added that based on another report on 161 cities, only 16 cities met national standards in 2014, mostly located in the Pearl River Delta⁸ region.

齐补充说，根据对161个城市的另一份报告中，2014年只有16个城市达到国家标准，这些城市主要分布在珠三角地区。

The article also said the density of PM2.5 generally peaks in winter and drops during summer. Aside from geographical⁹ factors, a greater amount of PM2.5 is found in spring in the northwestern, central and western parts of China and autumn in eastern China due to sandstorms and open biomass burning.

文章还称PM2.5浓度的最高值一般在冬季，夏季期间有所下降。除了地理因素，在西北部、中部和西部地区，春季由于沙尘暴影响，；在东部地区，秋季因露天的生物质燃烧，PM2.5浓度也较高。

A report released by environmental campaign group Greenpeace in July showed that PM2.5 density ranked highest in Beijing, Henan and Hebei provinces, while Yunnan and Hainan provinces as well as the Tibet Autonomous¹⁰ Region enjoy the best air quality.

由环保运动绿色和平组织在七月发布的报告显示，PM2.5浓度在北京、河南、河北等省排名最高，而云南和海南省以及西藏自治区能享受到最佳的空气质量。

The density level of PM2.5 particles in a day radically¹¹ changes after 4 pm, since vehicular traffic increases, according to the article.

PM2.5一天的浓度水平在下午4点以后会发生很大的变化，因为车辆流量增加，根据文章指出。

The article added that the government needs to determine the specific cause in certain places, as the PM2.5 density varies from place to place and at different times.

文章还指出，政府需要确定某些区域高的具体原因，因为地域和时间不同，PM2.5浓度也各不相同。

Zhang Yuanxun, an expert at the Chinese Academy of Sciences, told the Global Times that it took time to tackle the problem, and has called for stricter law enforcement and harsher punishments.

张元勋，一位中国科学院专家，告诉环球时报，解决这一问题需要时间，并呼吁更严格的执法和更严厉的惩罚措施。

China has implemented¹² a new environmental protection law, dubbed¹³ as the strictest ever law.

中国已经实施了新的环境保护法，并被戏称为有史以来最严格的法律。