The Changing Concepts of Smog in Modern China

Smog is a specific type of air pollution resulting from a complex of industrialization and modernization. The concept of smog is new to China. In the 21st century, having experienced severe smog across all of China, people recognized the haze filling the skies was no longer simply fog but a result of polluted air. The perception of this specific air pollution came from the direct experience of smog, and the use of the modern term wumai (雾霾, smog).


Smog is a specific type of air pollution resulting from a complex of industrialization and modernization. The concept of smog is new to China. In the 20th century the term smog was translated yanwu (烟雾, mist and fog) in Chinese. Without a direct experience of smog in the 20th century, Chinese people’s understanding of smog was very limited and strongly influenced by the term yanwu, which to the majority, was not necessarily connected to serious air pollution and health problems. In the 21st century smog appeared more and more frequently and the scope expanded from the Pearl River Delta and northern China to the whole country. Having experienced severe smog across all of China, people recognized the haze filling the skies was no longer simply fog but a result of polluted air. The perception of this specific air pollution came from the direct experience of smog, and the use of the modern term wumai (雾霾, smog). Since 2013, wumai appeared widely in the media, attracted a lot of attention in Chinese society and became the term for smog in connection with the dangerous air pollution across China. The significance of this shift shows how people’s understanding of smog has developed.

In 1905, the term smog was coined in the English-speaking world

In 1905, the English term smog was coined by Dr. Henry Antoine Des Voeux in his paper, “Fog and Smoke” for a meeting of the Public Health Congress in London[1]. He combined two words, smoke and fog, to create a new term smog. It referred to a type of air pollution that was caused by the heavy use of coal in industries and home heating. In the 1950s-1960s, the term smog appeared frequently in newspapers and journals because of the heavy air pollution in London and Los Angeles. In the 20th century, in the English-speaking world, the term has been included in dictionaries in reference to a harmful mixture of fog and smoke[2].

In the 20th century in China, smog was translated to yanwu (烟雾)

The London Smog of 1952 was translated to 伦敦烟雾 or 伦敦大雾 (London smoke and fog, or London big fog) in the Chinese newspapers and journals. Either the term yanwu or dawu, it is connected with fog, which has nothing to do with air pollution. Then why was the term yanwu used to refer to smog? Yan (烟, smoke) has literally meant smoke, while wu (雾, fog) has been fog. The English term smog came from a combination of smoke and fog, which found its equivalent combination in the Chinese language, i.e. yanwu. Although yanwu looks as if it follows the same principle for making the word smog, the term yanwu was not a newly coined word in Chinese in the 20th century. It had appeared in classical Chinese long before the term smog was introduced to Chinese. More importantly, yanwu, however, did not mean air pollution, but fog and mist before the concept smog was introduced to China. Although the meaning of yanwu was connected to air pollution, its original meaning (i.e. fog, mist) has had a stronger influence due to the fact that people were lack of direct experience of smog in the 20th century. People’s link between air pollution phenomenon and yanwu was relatively limited, compared to the modern term wumai.

In the 21st century in China, wumai became a term for smog

Both wu and mai were found in oracle bones and have been used for two different weather phenomena. Oracle bones were a tool for people in ancient China to practice divinations. Meteorology and astronomy in ancient China were recorded by historiographers in 《天文志》 (History of Astronomy) as a part of historical books 《二十四史》 (The Twenty-Four Histories[3]). The purpose of observing meteorology and astronomy in ancient China was for practicing divination to predict natural disasters, or the rise and fall of a dynasty. The book 《释名》(Shiming) is a glossary dictionary written by Liu Xi (25-220) in the Later Han period. In this book, wu was explained as a state of gas rising from the land. (“雾,冒也,气蒙乱覆冒物也.”) The earliest definition for mai was in the Jin dynasty recorded in 《天文志》(Tianwenzhi) of 《晋书》 (Jinshu, Book of Jin). “凡天地四方昏蒙若下尘,十日五日已上,或一月,或一时,雨不沾衣而有上,名曰霾”。[4] According to ancient people, mai meant that the sky was dark, like dust coming from above, and the phenomenon lasted for over 15 days, sometimes for one month, or even one season. It was like rain but clothes did not get wet. It also felt like dust in the air. In practicing divinations in ancient China, wu was not necessarily seen as a bad sign, but mai was regarded as a very negative sign that could indicate dangers of losing the kingdom of the emperor.

The use of wu and mai has not changed in modern China. In modern Chinese, wu refers to small drops of water coming together to form a thick cloud close to the land. Mai means a mixture formed by heavy smoke and dust in the air[5]. In this way, it is not so surprising to see that people used wu and mai together to refer to a mixed weather condition in 2004 when air pollution started to be more obvious and serious.

In 2004 wumai as a term for smog was first reported in the Beijing Daily.[6] However, although wumai was used to refer to a weather phenomenon after 2004, due to the limited understanding about its cause and impact, the term wumai was used to refer to a mixture of fog and smog, rather than as a clear concept for air pollution. In that period, meteorologists were keen to distinguish the difference between fog and smog for the purpose of providing the government and public with environmental protection measures. Thus, articles published in the field of meteorology on the topic of smog mainly focused on explaining the difference between fog and smog, as well as what smog weather referred to.

It was not until the year 2013 that the term wumai became a widely-used term for air pollution in China. The leading researcher at the Institute of Tropical and Marine Meteorology in China, Wu Dui is one of the group of scientists doing the research on smog since 2002. In 2015 Wu argued in a phone interview in the media that how wumai became a term for smog was a coincidence, a slip of the tongue of a weather reporter, and more importantly, it was not a correct term for smog in meteorology. He argued that the term huimai (灰霾, gray haze) is the correct Chinese term for smog. Wu pointed out that in 2013, with the increasing smog weather across all of China, the term wumai came from a mistake made by a weather forecast reporter on CCTV. Due to time limitation to report fog and smog in every city in China, a reporter combined them and said the area of North China Plain might have wumai, rather than there might be fog in Henan and smog in Beijing and Hebei.[7] After this coincidence, the term wumai has been widely promoted in the media with reference to people’s direct experience of air pollution and then the term was quickly accepted and became the term for this specific air pollution — smog. Ironically, Wu commented that the incorrect term wumai has been more popular than huimai, the real name for smog among the population.

Actually, wumai as a term had been used before 2004, it had not been used to refer to a meteorological phenomenon, but as a technical term referring to haze in optics. According to articles identified in the database Quanguo baokan suoyin (QGBKSY) 全国报刊索引[8], wumai appeared 3 times in Chinese newspapers and journals in 1930-2003 (twice used in the field of optics and once used in a fiction). In 2004-2012 the frequency of wumai steadily increased to 13 (11 times used for weather phenomenon and twice used in the field of optics) and reached 61 in 2013, 145 times in 2014 and 136 times in 2015. It indicates that the term wumai as haze in optics was not known to most of the Chinese people before 2004. However, because of the serious air pollution which people have experienced and the media’s promotion of the term wumai for smog, the term wumai has become known to people for air pollution. As a result, in the 21st century the term wumai has been imbued with the new meaning of air pollution.

Wumai became a concept for dangerous air pollution!

Since 2013, due to the serious air pollution in China, the term wumai has frequently appeared in the media, in people’s daily life and even in the agenda of the National People’s Congress and the Chinese People’s Political Consultative Conference. In Beijing for example, where the air pollution is so serious, in 2014 the number of days with heavy smog reached 175[9]. It means that for nearly half a year people in Beijing were living with no fresh air to breathe, many chose to wear masks when going out, parents were afraid of children being exposed to air pollution when playing outside, and people were afraid of getting lung cancer from smog.

Since 2014 smog has hovered over China. It happened often that in each city with heavy smog, people couldn’t see things beyond the range of 5 meters, and even public buses got lost because of the low visibility. Smog has become one of the most popular topics in daily conversation among the public, entrepreneurs, government officers, scientists etc., in relation to how smog may cause health problems, affect economic growth and the sustainable development of China.

The changing concepts of smog in modern China show how people’s understanding of this specific air pollution has developed. In this process, the meanings of an ancient term yanwu and a modern term wumai were extended to refer to smog in the 20th and 21st centuries respectively. Although from the perspective of meteorologists, the term wumai is not the correct word for smog, it has become a concept of dangerous air pollution among the population. With further research and experience of smog in China, it could happen that the term huimai or a new word might be used for smog as a more precise term and widely accepted by the population in the foreseeable future.


[1] Whyte, Murray. “Dr. Des Voeus and the invention of smog.” 2007.6.10, from

[2] Collins Concise Dictionary of the English. 1978. Collins

[3] The Twenty-Four Histories are the Chinese official historical books covering a period from 3000 BC to the Ming dynasty in the 17th century.

[4] Ni, Liufang. zhongguo gudai wumaitian zuizao chuxianyu heshi 中国古代雾霾天最早出现于何. Beijing Wanbao. 2014-12-05 from

[5] Xiandai hanyu cidian现代汉语词典 1996. Beijing: Shangwu yinshuguan 商务印书馆

雾:气温下降时,在接近地面的空气中, 水蒸气凝结成的悬浮的微小水滴。Wu: when temperature is decreasing, water vapor come together to form small drops of water close to the land.”

霾:空气中因悬浮着大量的烟,尘等微粒而形成的混浊现象。通称阴霾。Mai: something such as heat or smoke in the air which makes it less clear.

[6] Zhang, Jun. Benshi zuo chuxian shaojian wumaitian本市昨出现少见雾霾天. Beijing Daily. 2004.6.29. No.8

[7] The mistake made by the weather reporter is discussed in the interview between the scientist Wu Dui and the interviewer from the magazine of China National Georgraphy. See the article: Shan, Zhiqiang. “专家说: “雾霾”这个词已经泛滥成灾” Zhuanjia shuo: “wumai” zhegeci yijing fanlanchengzai. 中国国家地理. Chinese National Geography. 2015.03 from

[8] Quanguo baokan suoyin (QGBKSY) 全国报刊索引 (national newspaper and periodical index database). It is the earliest comprehensive search tool of Chinese newspapers and periodicals in China. It provides the Late Qing Dynasty Periodical Full-test Database (1833-1911), Chinese Periodical Full-text Database (1911-1949) and Chinese Periodical Index Database (1950- ). QGBKSY is provided by Shanghai Library.

[9] Chai Jing's review: Under the Dome – Investigating China’s Smog. 2014

Irene Xu is a master student in East Asia Culture and History at UiO’s Department of Culture Studies and Oriental Languages. Her main academic interests are the languages, concepts and history.

By Irene Xu
Published Feb. 1, 2017 10:40 AM - Last modified Jan. 7, 2021 1:19 PM