In the last decade, authorities have brought in policies to mitigate the city’s unhealthy air quality. As a result, the average annual PM2.5 concentration in 2018 was half that of 2009, (101.8µg/m³ in 2009 versus 50.9µg/m³ in 2018), while the number of healthy air quality hours annually nearly quadrupled (5.5 percent of hours in 2009, to 21 percent of hours in 2018). However, while Beijing’s air quality is improving by the year, more needs to be done for the city to attain annual PM2.5 levels that meet the World Health Organization’s guideline of 10µg/m³.
The largest sources of locally-generated PM2.5 in the capital are vehicles emissions, followed by road and construction dust. Beijing has 5.64 million private cars, and has cut the number of license plates issued each year down to 100,000, as of the end of 2017. In 2017, Beijing shut down the last of its four coal-fired power plants in its transition to natural gas. However, Beijing suffers from its valley topography; much of its pollution comes from outside the city and builds up until strong winds carry it away.
As the capital of the world’s most populous country, Beijing’s air quality has drawn global attention and is seen as a reflection of the national environmental condition.
For many years, public air quality records lacked transparency. In 2008, the US Embassy began tweeting real-time measurements recorded by the US Embassy air monitor a PM2.5 Beta Attenuation Monitor. The readings revealed a stark reality, previously unknown to the world and underestimated by residents. While Twitter is blocked in China, the data spread via Chinese sites and third-party apps, raising public awareness. Inadvertently, this placed mounting pressure on Chinese officials to both acknowledge the severity of the problem and begin taking measures to tackle it.
In September 2013, the Chinese State Council issued an Action Plan for the Prevention and Control of Air Pollution, which included implementing a comprehensive, nationwide air pollution monitoring system. Today, Beijing city has a monitoring network of 34 government stations, which report real-time measurements, in line with US Embassy data.
While efforts have proven successful in meeting or exceeding goals set by the Chinese government, Beijing still averages air quality more than four times the WHO recommendation. Among global cities with air quality monitoring stations, Beijing ranked 122nd for the world’s worst air quality, and 72nd among Chinese cities, in 2018.