World Changing Ideas: Urban Air

Urban Air More than half of us live in cities, and while we might complain about the state of the roads, or property prices, most of us take more basic facilities for granted: access to clean water, waste disposal, and breathable air. But our cities are already struggling to provide the last thing on that list. Air is even more essential than water.

World Changing Ideas: Urban Air
Illustration: Oliver Munday Illustration: Oliver Munday

Urban Air

More than half of us live in cities, and while we might complain about the state of the roads, or property prices, most of us take more basic facilities for granted: access to clean water, waste disposal, and breathable air. But our cities are already struggling to provide the last thing on that list. Air is even more essential than water. We can’t survive even a few minutes without it, and yet our cities, from London to Beijing to Sao Paulo, have atmosphere’s so polluted that residents are often warned not to leave their homes unless they have to. It sounds like the aftermath of a natural disaster, and it is, only–unlike a natural disaster–it’s not over. Our air is getting worse, not better.



Air pollution comes down to particulate matter, tiny particles small enough to enter the cardiovascular system and major organs where they wreak havoc on our bodies from the inside. Air pollution comes from several main sources: Manufacturing, burning fuel for heating and cooking, burning coal for energy, and burning gasoline in vehicles. In short, burning stuff is the problem. A 2016 study breaks it down like this: 25% of urban pollution comes from traffic, 15% from industrial activities, 20% by domestic fuel burning, 22% from “unspecified sources of human origin,” and 18% from natural dust and salt.

Cities might be efficient machines for living, but when we collectively burn gas to heat our homes, and collectively sit in traffic every morning, they become like swimming pools where everyone tinkles in the water instead of visiting the bathroom. And because the concentration of humans is greatest in cities, the filthy air can really get to work on a good chunk of us.

Worldwide, more than 5.5 million people die prematurely each year, with over half go those in China and India, according to researchers from the University of British Columbia’s School. The WHO says that, in 2012, air pollution contributed to 6.7% of all deaths that year. Fixing the problem seems almost impossible. For instance, even if China meets its current targets to reduce pollution through energy policies, and curbing coal, by 2030 up to 1.3 million people will still be dying prematurely each year. That’s barely less than the 1.4 million that currently die early each year.

Air pollution, or particulate matter (PM), causes both short-term and long-term health problems. Short term, it can aggravate lung disease, make us more susceptible to respiratory infections. According to the EPA, you may become short of breath, feel tightness in the chest, and irritation in the eyes, nose and throat. Long term, the tiny particles work their way into your lungs, blood, and organs, and can cause cancer, lung disease, and chronic illnesses like bronchitis. If you already have heart disease, pollution can bring on a heart attack without warning, even if you have no other symptoms. In short, even though we can’t see the problem, dirty air is attacking us the whole time we’re exposed to it.

And it’s not just humans that suffer. Toxic air will settle into water, polluting waterways, and entering the food chain. And that’s all before we get to the climate change that’s another by-product of burning all that fuel.


The solutions are obvious. Get heavy industry out of cities, increase the efficiency of heating (and cooling) by properly insulating buildings, and remove as many polluting vehicles as possible from the roads. Of these, getting rid of cars and trucks might be the fastest route to cleaner air, if only because making our homes more energy efficient is such a long-term plan, relying on refurbishment, or replacement, of occupied buildings. Traffic is also the biggest cause of urban air pollution, contributing 25% according to a study published in 2015 (industrial activities make up 15%, and domestic fuel burning 20%). But reducing traffic isn’t easy.


Take Mexico City as an example. Famously polluted, locals said that the air was so soupy that just breathing it was “like smoking two packs of cigarettes a day,” writes PRI’s Monica Campbell. Pollution researcher Gabriela Alarcón told Campbell that “We saw birds that suddenly fell down. They fell out of the sky and they were dead.”

20 years ago. Mexico City started to move heavy industry out of the city, and invested in public transit. And it worked–for a while: As the city grows, most new residents come to live on the outskirts, and are forced to drive due to a lack of transit option. Air pollution is on the rise again. Mexico City uses one of the oldest traffic management schemes around, introduced in 1989: Cars are banned for one day each week based on the last digit of their license plate. Athens was the first to restrict cars this way, in 1982, and other cities have since followed: São Paulo, Brazil, in 1995, Bogotá, Colombia in 1998, Beijing in 2008, and most recently Delhi in 2016. Recently, the city extended this program, called Hoy no circula, to Saturdays, but it didn’t work. “Across eight major pollutants,” says a paper published in Nature’s Scientific Reports, “the program expansion had virtually no discernible effect on air quality. The estimated impacts are close to zero.”

Similarly, London’s Congestion Charge, a daily tax levied on vehicles which enter the city center, had a big impact when it was introduced in 2003. In the , the 60,000 fewer cars and vans entered the zone, with around half of those drivers switching to public transport, and journey times for remaining vehicles reduced by 14%. Today, however, there are calls from the London Assembly transport committee to scrap the current fixed charge in favor of a city-wide pricing scheme that would target peak hours and the city’s business roads.

London is currently locked in a war on air pollution. The capital’s air is infamously deadly, killing 10,000 people every year, and mayor Sadiq Khan is intent on cleaning it up. He has already implemented the “standard” measures: , from diesel buses, and investing big in alternative transport by spending $1 billion on cycling. This year, though, Khan is getting serious, with some radical new plans. One of these is a T-Charge, where the T stands for Toxicity. This adds another £10 on top of the existing £11.50 Congestion Charge, bringing the total to USD$26.60. The charge will apply to pretty much any vehicle built before 2006, and will–estimates the Mayor’s office–affect around 10,000 of the vehicles entering London every day.

Critics of the new T-Charge say that it’s impact will be “negligible,” affecting only 7% of vehicles entering the zone, and will only reduce polluting NOx gases by 1-3%, according to Transport for London’s own report. And while it is still too early to gauge the impacts of Sadiq Khan’s clean air plan for London (he only took office in 2016), the effects of other traffic reduction schemes have been positive. London’s bike-sharing system, for example, has made the population healthier, and another study, from the University of Cambridge, shows that even in polluted cities, the exercise benefits of cycling outweigh the risks.

Perhaps more than any other European city, Paris has made its intentions to reduce traffic clear. Mayor Anne Hidalgo has enacted , commissioned to favor pedestrians, changed the law to , and from the city center. Perhaps the most startling action by the mayor was to close a two-mile stretch of a major road along the Right Bank of the Seine entirely. The result wasn’t the chaos you may expect. While some of the traffic was displaced onto nearby traffic arteries, most of it just disappeared. Only half of the vehicles that used to run on the road by the river each hour reappeared on nearby roads, a figure which surprised everyone, even the mayor’s own predictions were more conservative. More than anything, though, this closure shows that the common wisdom–that closing roads will worsen traffic congestion–simply isn’t true.


In China, plans are even more radical, with proposals for forest cities which cover tower blocks with vertical gardens. These cities, proposed by Italian architect Stefano Boeri, could provide oxygen to counteract pollution, as well as regulating the temperatures of the buildings themselves. The first towers are going up in Nanjing, to be completed in 2018, and will absorb 25 tons of CO2 each year, and provide 132 pounds of oxygen every day.

And Nanjing could use the help. In 2012, Greenpeace compiled a list of China’s 28 most-polluted cities. Nanjing came in at number 27, with only Beijing faring worse. Nanjing’s PM10 level is 185% of the Chinese standard, and 570% of the WHO standard. Boeri’s towers won’t save the city–he describes it as a “skin graft”–but the Chinese government is realizing that its giant megacities aren’t sustainable, and is looking at greener, cleaner models. “We have been asked to design an entire city where you don’t only have one tall building but you have 100 or 200 buildings of different sizes, all with trees and plants on the facades,” Boeri told the Guardian.

Citizen Action

While city governments are the most important tool in the fight to clean up urban air, the citizens themselves can also help. In Stuttgart, Germany, a scheme called Luftdaten (air data) provides sensors for residents to hang outside their homes. The sensors measure pollution levels, and in one neighborhood of Stuttgart those levels have gotten so high that the residents have sued the city’s mayor, and the district president, for causing bodily harm by failing to address the city’s poor air quality. This is not the first time citizens have taken legal action against air pollution in Stuttgart. In 2008, shortly after the European Court of Justice ruled that citizens can use the courts to fight excessive air pollution, two Stuttgart residents threatened to sue the city if steps weren’t taken to clean things up.

The city has taken some measures, but they have so far been ineffective. For instance, on days when pollution exceeds EU limits, for instance, public transport tickets are reduced to half fare to encourage people to leave their cars.

But reducing fares on bad-air days won’t do much to help. After all, if you drive to work every day, would you really break your whole routine just because the metro is a dollar cheaper than usual? To make any real change, habits have to be broken. With commercial traffic, the law can force changes. In London, the city has invested in an electric delivery vehicle company, for example. But to get private citizens out of their cars, you need to make driving as painful as possible. As long as people can keep on doing what they’re doing, they will do it.

One example of a city that’s not afraid to piss off its citizens is Barcelona. The Catalan capital’s Superblocks may be the most exciting anti-traffic scheme running today, and are a model for other cities. What is most notable about the blocks is not the actual scheme itself, but the political will from populist mayor Ada Colau. In principle, the Superblocks are cheap and easy to implement. They divide Barcelona’s road grid into nine-block squares. Through-traffic can only use the perimeter roads, and the city’s bus routes have already been completely re-designed to fir the new layouts. Anyone entering the Superblock in a var will be guided straight back out again. Re-using the reclaimed spaces for pedestrians is part of the plan, but to function, the Superblocks only need to change traffic flow with new signage.


The changes have met with street protests, but Colau is pressing on, intent on covering the city with Superblocks by 2018. The pace of change–enabled by the simplicity of the changes–might be one of of its biggest strengths. If all goes to plan, Barcelona could reduce traffic and clean up its air before the car lobby manages to find a parking spot and start complaining. The city hopes to free up half of the land currently dedicated to traffic, reclaiming almost three square miles, and give that space back to pedestrians. At the same time, the reduction in traffic is hoped to bring levels of NO2 below 40µg per m2 across 95% of the city, up from 67% today.

Grand plans like China’s forest cities are nice and all, but the real changes are happening in cities with strong mayors: London’s Khan, Paris’s Anne Hidalgo, and Barcelona’s Colau are all intent on cleaning their city’s air, and they don’t care if they step on toes to do it. The time for pandering to the car and oil lobbies has long passed. Thankfully, the measures being taken by these thick-skinned public officials are having positive effects that are obvious to everyone.

And really, what is the alternative? Vehicles cause a quarter of all the pollution in cities, so they have to go. Otherwise, we might have to start buying bottled air, just to breath. And while that may sound like a joke, it’s far from it.

About the author

Previously found writing at, Cult of Mac and Straight No filter.