For a few days late last month, “a cocktail of high atmospheric pressure, little wind and peak farming season emissions” left London with more-polluted air than Beijing, Bloomberg News reported. These worse-than-Beijing episodes are likely to occur more and more frequently — not because London’s air is getting worse, but because Beijing’s has gotten so much better.
The concentration of particles less than 2.5 micrometers in size, known as PM2.5, in the air over Beijing remains well higher on average than in London. The city’s air quality is also quite variable, with unfavorable weather conditions in winter and early spring still bringing episodes of terrible pollution. But huge ongoing differences in air quality between Beijing and the major cities of the developed world seem to have become a thing of the past, while other big cities in the developing world now dominate the pollution charts.
During its great economic rise in the 1990s and 2000s, China became what scientific journal The Lancet dubbed the “air pollution capital of the world.” Although the pollution was even worse in some of the country’s inland industrial cities, Beijing became a global byword for dirty skies.
It owed this reputation in part to the US State Department, which in 2008 installed an air monitor on the roof of its Beijing embassy and began posting hourly PM2.5 readings on Twitter. The automated tweets included US-Environmental-Protection-Agency-derived assessments of whether the air was “good,” “moderate,” “unhealthy for sensitive groups, “unhealthy,” “very unhealthy” or “hazardous.” One day in 2010 the concentration exceeded the EPA’s 500-point scale, triggering some code in the embassy’s program that labeled the air quality “crazy bad.”
The readings and the global headlines they generated were an embarrassment to the Chinese government, which in 2012 demanded that the US and other foreign embassies stop publishing such information, declaring that doing so constituted interference in the country’s internal affairs. Instead of following through on that, though, Beijing greatly expanded its own air-quality measurement and reporting systems and cracked down big-time on pollution. The US Embassy’s @beijingair account is still going strong, but now tells pretty much the same story as the official Chinese statistics — one of great improvement over the past decade.
The cleanup of Beijing’s air has been accomplished mainly by replacing coal with natural gas in home heating and cooking, industrial use and electricity generation. Restrictions on car and truck use and emissions have also played a role, as has the city’s status as a leading electric-vehicle early adopter. A recently concluded investigation by scientists from the UK and China found that Beijing itself was producing far less pollution than expected, with most of its bad air days now due to pollutants drifting in from rural areas and other cities to its south. Beijing also bears the brunt of occasional sandstorms blowing in from the Gobi Desert, although even those have declined in frequency thanks at least in part to the massive Great Green Wall reforestation program.
Beijing is the capital and one of the country’s richest cities. Not everywhere in China has the resources to take such steps — the country simply doesn’t have enough natural gas, for one thing. But in general China is shifting to cleaner sources of energy. Coal still dominates electricity generation but the trend is clear.
The point of recounting all this is partly just to spread the word that Beijing’s air isn’t (usually) so dirty anymore. Much has been written about its improving air quality (including a column by me, way back in 2016), but it clearly hasn’t fully sunk in, given that “worse than Beijing” remains a go-to phrase for headline writers describing cities in the midst of pollution alerts. It’s time for an update. To be really, truly awful, your city’s air now has to be “worse than Delhi.”
This is also a plea for a little environmental optimism at a time when pessimism seems to have the upper hand. In the late 1800s and early 1900s the air in London was even worse than it is in Delhi now. Increasing affluence, technological advances and deindustrialization have led to a situation where, occasional freak events aside, the air over the city is generally quite fit to breathe.
Higher incomes don’t automatically bring cleaner air — Oman, Bahrain and Qatar are all pretty rich, yet the residents of their capitals have to put up with terrible pollution. It sure does seem to help, though: A recent World Health Organization update of global air pollution data found that only 17% of cities in high-income countries fell below its Air Quality Guidelines for PM2.5 or larger PM10 particle pollution, while in low- and middle-income countries 99% did. Rising out of poverty tends to entail huge increases in per-capita energy consumption and lots of pollution. But affluence brings slower growth in energy use and sometimes outright declines, as well as resources to combat the unwelcome side-effects.