Exhausted by pollution? — How to improve air quality in cities (part 1)
Improving urban mobility
(by Gyorgyi Galik, with contributions from Jonathan Broderick)
This series of blog posts is a collection of insights that I’ve been gathering over the last decade on how to improve air quality in cities. It’s far from being complete but I hope it might help to better understand the complexity of pollution and the possible actions/steps we can take to improve it.
Enforce stricter emissions standards
The impact of air pollution could be greatly reduced by enforcing stricter emissions standards on both diesel and petrol cars. Private and public vehicles should be tested more frequently, based on real-world rather than laboratory emissions. Improved testing regimes will be more likely to catch out bad performing vehicles and therefore lead to a cleaner fleet over time.
Reduce unnecessary car journeys
Cities should encourage people to make short journeys through cycling or a combination of public transit and walking (otherwise known as active travel). Short journeys in cars have a huge impact on air quality and need to be reduced and driving behaviour needs to be changed to make an impact.
Most journeys in the UK and European cities do not require a car. Looking at all of the journeys, for example, in the UK made by car (in 2013) 60 percent were between two and five miles , 11 % of that 60% were under a mile and 29 % were between one and two miles. To convince people to leave their cars at home, they need to understand the pollution they are contributing to the city and the health benefit they will gain by walking, running and cycling (active travel) and combining these with public transport. This is where the government needs to ensure that there is a clean/green public transport network. Public transport can be converted for diesel to electric but it is only decarbonised if the electricity that powers it is generated through renewables and not by burning coal in a distant power station.
Change the common perception — Drivers are the most affected by pollution!
Sir David King explains “even if you are driving a cleaner vehicle you will still be exposed to toxic gases from the vehicles around you — while it might feel like you can wind up your windows and seal yourself into the safety of your car, that is far from the case” .
The highest levels of air pollution are monitored in the car, followed by the person travelling by bus. Numerous studies have shown that a driver actually breathes in higher amounts of pollution than a cyclist or pedestrian on the same road. Children sitting in the back seat are the most vulnerable and likely to be exposed to dangerous levels. It’s been also shown that the health benefits of walking and cycling outweigh the costs of breathing in pollution . While this is still the case in London, Paris and New York, in at least 15 cities around the world, air pollution is so bad that the health impact of even 30 minutes of cycling each way outweighed the benefits of exercise altogether. As Damian Carrington (2017) explains:
In cities such as Allahabad in India, or Zabol in Iran, the long-term damage from inhaling fine particulates could outweigh the usual health gains of cycling after just 30 minutes. In Riyadh, Saudi Arabia, this tipping point happens after just 45 minutes a day cycling along busy roads. In Delhi or the Chinese city of Xingtai, meanwhile, residents pass what the researchers call the “breakeven point” after an hour.
Make public transit more attractive
It is generally accepted that increased public transit ridership and making public transport cleaner would greatly improve urban air quality.
Getting people out of their cars and into public transit in the first place depends on making it attractive to potential users. Evidence shows that the two biggest factors in doing this are service reliability and frequency . This was best demonstrated in Curitiba, Brazil, in the early 1990s when the city revamped its bus rapid transit (BRT) system with an improved station design and a universal payment system . As the population continues to increase, mobility is a big challenge for most cities. To address this problem many places from Singapore to San Jose are also piloting on–demand services that enable people to use their smartphones to order a bus. All of the requests by individuals are analysed to create an optimal route. It is hoped that these services will be more convenient in certain places than a regular bus but cost less than a taxi.
Encourage active travel (walking, running and cycling)
As Dr Gary Fuller argues by increasing active travel we could not only improve air pollution but also urban noise and ill health from inactivity . There is no single intervention that will encourage walking or cycling on its own. Getting people out of their cars and onto a bike requires a combination of actions. To name a few, cities should re-allocate road space to provide better physical safety for cyclists (with consideration for elements such as traffic proximity, speed limits, visibility, safer intersections, and access to maintenance facilities). To make cycling more appealing for commuting (and not just leisure) cities should also consider the flow of cycling — or the ease with which cyclists can move from point A to B without interruptions such as red lights, traffic, and pedestrians.
Copenhagen is a good example of a city that has put several of these elements into practice. To improve flow, the city introduced the Green Wave, a technology that coordinates the traffic lights for cyclists . If cyclists ride at a speed of 20 km during the morning rush hour, they will hit green lights all the way into the city. To improve safety, the city introduced pulled back stop-lines for cars; a three-second advance on green lights for cyclists; and painted cycle paths to guide cyclists through busy intersections. The city has also taken steps to foster a cycling culture by introducing features such as extra-wide cycle tracks, so families and friends can chat while commuting to work together. As Leanna Garfield  explains “today, over half of Copenhagen’s population bikes to work every day” — with one of the lowest rates of car ownership in Europe — “thanks to the city’s effort to introduce pedestrian-only zones starting in the 1960s”. Garfield also lists 13 different cities across the world (from Hamburg and Oslo to Mexico and Chengdu) who are all starting to ban cars.
Demand fewer not only cleaner vehicles in cities — Electric vehicles are not the silver bullet!
The chair of the UK government advisory committee on the medical effects of air pollution and professor of environmental health at Kings College London, Frank Kelly  argues that
electric car use should also be limited and deterred by taxes/fines in addition to diesel and petrol cars. All cars need to be banned or drivers need to be dissuaded from using them if targets are to be met.
It’s a little known fact that a lot of pollution comes from tyre and brake wear, and by vehicles throwing up dust from roads — not only from exhaust fumes. One study suggests that non-exhaust emissions account for over 90% of PM10 and 85% of PM2.5 emissions from traffic . And another European Commission research  found that about 50% of all particulate matter comes from non-emission sources. Tyre and brake wear is the biggest contributor of PM2.5 in the UK. As Professor Kelly explains particle pollution will still be present if the quantity of vehicles on the road remains the same. As EVs are — at the moment at least — still heavier because of their batteries, they contribute large amounts of PM2.5 from their tyres. So — even if it improves pollution levels — EVs are not the silver bullet. They should be carefully regulated and combined with public transport, walking, and cycling.
Get rid off free and cheap car parking spaces
The research of Andrea Hamre and Ralph Buehler  at Virginia Tech from the Washington, DC region showed that “commuters offered either public transportation benefits, showers/lockers, or bike parking, but no free car parking, are more likely to either ride public transportation, walk, or cycle to work”. However, as the writer of Fast Company, Adele Peters  notes “give employees the [free] option, and they’ll almost always choose driving over other forms of commuting.” Although increasing car parking charges are politically unpopular (involving a lot of opposing interests), many cities and local authorities recognise the key role of car parking prices in enabling behaviour change and reducing the number of cars on their roads.
In 2018 the City of London Corporation, for example, introduced new charges for on-street parking in London’s historic financial district, the City of London. Parking charges use an ‘emissions-based’ system, which is designed to target high polluting vehicles with higher charges . Introduced in 2018, new residential developments in London should not exceed the maximum parking standards set out in the Draft New London Plan either .
Following consultations with their residents, new charges are currently being introduced in Merton Council in London. These charges “apply to controlled parking zones, public parking zones, public car parks, on-street parking and parking permits” in the borough. The initiative started in January 2020 “aims to discourage the reliance on car use to reduce toxic pollution from vehicles, and to help residents enjoy the health benefits of taking more journeys by bike, on foot and by public transport” .
Change driving behaviour
In the short-term, cities could reduce air pollution by encouraging drivers to change their driving behaviour. If drivers were to adopt more efficient driving practices — such as minimising engine idling, maintaining steady speeds, and avoiding sharp acceleration and braking — they could significantly reduce their fuel consumption and carbon dioxide (CO2) emissions  . Evidence shows that driver training (both private and employee drivers) can lead to a lasting decrease in fuel use of up to 6.5–10 percent .
Other interventions including changing company regulations (e.g. flexible working hours, WFH), redesigning freight, consolidation, and logistics, making public transport cleaner and more accessible, introducing cleaner taxi fleets and car-sharing schemes, and reallocating road space to give priority for pedestrians and cyclists are equally effective in improving air quality.
You can find all the bibliography and references here
If you’re interested in what else cities can do to improve air quality please read Part 2 on How to improve air quality in cities.
(I really appreciate/welcome any comments and ideas. Please send your thoughts to email@example.com)
Gyorgyi Galik is a London-based innovation designer, design strategist, and environmental advocate. She is a Lead Advisor and Programme Manager at Design Council’s Cities Programme. She is also at the finish of her Ph.D. studies in Innovation Design Engineering, School of Design at the Royal College of Art. With a background in social design, behavioural science, and environmental health, she has more than a decade of experience delivering experimental research, design and technology projects in the corporate, governmental and non-governmental sectors.