Air pollution – the downside of greater mobility

Urban life 7 July 2017 Julia C. Lester

Every year, air pollution kills millions of people globally. Emissions from heavy traffic and congestion are among the biggest culprits. Ambitious air quality strategies are needed to reduce this growing health threat.

4 min

Air pollution is a major environmental health problem affecting everyone around the world, from Manila to Sao Paolo to London. In 2014, WHO released new estimates showing that exposure to air pollution killed around seven million people in 2012 – one in eight of total global deaths. This finding was more than double the previous estimates, and air pollution has now become the world’s single greatest environmental health risk.

Although emissions from industries and private households impact urban air quality, traffic bears the brunt of the responsibility. The globally rising demand for instant mobility has led to a 57% increase in the number of motor vehicles worldwide.

Today, more than 1.1 billion cars congest the earth, causing the same pollution that would come from burning all the coal on a fully loaded train stretching 304,000 miles or 12 times around the equator.

Proactive rather than reactive initiatives

The problem is most pressing in the megacities of India and China, places like Beijing and New Delhi, but smaller cities in the USA and Europe are also suffering from increasing air pollution. How do cities tackle this challenge – and are they doing enough?

- Over the last 20-50 years, mobility and road safety have far and away been the predominant objectives of most large transportation and infrastructure projects conducted worldwide. Some countries have implemented legislation and other initiatives aimed at reducing air pollution from traffic. Most of these initiatives, however, tend to be reactive, not proactive, and we rarely see air quality as an end in itself when new large transportation and infrastructure projects are being developed, says Julia C. Lester, PhD, a former air regulator, now a principal and air quality expert at Ramboll Environ.


Some cities are trying to reduce human exposure to harmful pollutants from urban transport sources by reducing pollutants from mobile sources, limiting the number of people exposed to elevated concentrations of these pollutants and minimising the duration of their exposure.

Cities can reach these goals by implementing air quality management strategies that target automotive technology and fuels and by improving urban transport management as a whole.

- Although there are no universal air quality management strategies applicable to every city in the world, evidence suggests that a comprehensive, sustainable urban mobility approach would have a significant impact on emission reductions and result in extensive co-benefits through local improvements, says Julia Lester.

Such approaches include providing cycling and walking facilities or attractive and reliable alternatives to the private vehicle. Another option is to institute restrictions on car use or to produce cleaner technology and fuels for vehicles. Good land-use planning practices and advanced goods movement and logistics systems could also make significant contributions, as could monetary incentives created through the appropriate economic instruments.

The latest WHO estimates and multiple national/state air initiatives will spur companies to devise further measures to improve air quality.

Written by Martin Zoffmann.