WMA Statement on the Prevention of Air pollution due to Vehicle Emissions

Adopted by the 65th World Medical Assembly, Durban, South Africa, October 2014 


There are a number of ways in which the volume of harmful emissions can be reduced. These include encouraging fewer road traffic journeys, active transport for individuals undertaking relatively short journeys, the use of mass public transit in preference to individual vehicles, and alternative energy sources for vehicles, including electric and hybrid technologies. Where vehicle use is essential, means of reducing harmful emissions should be used.

Physicians around the world are aware of air pollution. It impacts the quality of life for hundreds of millions of people worldwide, causing both, a large burden of disease as well as economic losses and increased health care costs. According to WHO estimates, in 2012, urban outdoor air pollution was responsible for 3.7 million annual deaths, representing 6.7% of the total deaths (WHO, 2014).

Especially, diesel soot is acknowledged as a proven carcinogen (IARC, 07/2012). Furthermore, it has many other toxic effects, most prominently in the cardiovascular (Brook et al., 2010) and respiratory systems (ERS, 2010). Moreover, in the context of global warming, soot, along with methane, is identified as the second most important greenhouse driving force substance after CO2 (Kerr, 2013).

Despite the fact that new vehicles will have to comply with stricter emission standards which take into account most harmful ultra fine particles too, a high-polluting in-use fleet, including off-road vehicles such as construction engines and ships, will continue polluting for many more years.


In many densely populated cities around the world, fine dust concentrations measurable as aerosols exceed up to 50 times the maximum WHO recommendation. High volumes of transport, power generated from coal, and pollution caused by construction machinery are among the contributing factors. People living and working near major (high density volume traffic) streets are most affected by pollutants.
For fighting the health risks mentioned above, there exist a variety of highly efficient and reliable filter systems on the market (Best Available Technology (BAT) filters[1]). They are applicable to all internal combustion engines and they reduce even most harmful ultra-fine particles by a factor of over one hundred.
As soon as 90% of heavy duty vehicles, both, new and upgraded ones, satisfy this standard, health problems attributable to emissions of heavy duty traffic will be greatly reduced, and no further tightening of emission standards will be possible or even needed at all because of an almost total elimination of the pollutant as such.
In a variety of countries on different continents and under varying conditions retrofit or upgrading programs have been successfully performed. The UN’s Working Party on Pollution Prevention and Energy in Geneva has just proposed a technical standard for regulation in their member states, which will be applicable worldwide.
The WMA supports these efforts and calls on policy makers in all countries, especially in urban regions, to introduce regulatory restrictions of access for vehicles without filter, and/or to provide financial assistance to support the retrofitting of in-use vehicles.

The WMA therefore recommends that all NMAs should encourage their respective governments to:

  1. Introduce BAT standards for all new diesel vehicles (on road and off-road)
  2. Incentivise retrofitting with BAT filters for all in-use engines
  3. Monitor and limit the concentration of nanosize soot particles in the urban breathing air
  4. Conduct epidemiological studies detecting and differentiating the health effects of ultrafine particles
  5. Build professional and public awareness of the importance of diesel soot and the existing methods of eliminating the particles
  6. Contribute to developing strategies to protect people from soot particles in aircraft passenger cabins, trains, homes and in the general environment. These strategies should include plans to develop and increase use of public transportation systems.



 EPA: Environmental Protection Agency (US)

ERS: European Respiratory Society

IARC: International Agency for Research of Cancer

BAT Standards: Emission standards for passenger cars, heavy-duty vehicles and off-road machinery, based on count of ultrafine particles rather than mass and aimed at the protection of human health from the most hazardous soot particles, the lung and even cell membrane penetrating ultra-fines.


  • Brook, Robert D. et al. (2010): AHA Scientific Statement: Particulate Matter Air Pollution and Cardiovascular Disease. An Update to the Scientific Statement from the American Heart Association. Circulation 121: 2331-2378.
  • ERS (2010): The ERS report on air pollution and public health. European Respiratory Society, Lausanne, Switzerland. ISBN: 978-1-84984-008-8
  • IARC (2012): “IARC: Diesel Engine Exhaust Carcinogenic”. Press Release No. 213. http://www.iarc.fr/en/media-centre/pr/2012/pdfs/pr213_E.pdf .
    (access: 14/02/14)
  • Kerr, Richard R. (2013): “Soot is Warming the World Even More Than Thought”. In: Science 339(6118), p. 382.
  • WHO (2014): “Burden of disease from Ambient Air Pollution for 2012.” http://www.who.int/phe/health_topics/outdoorair/databases/AAP_BoD_results_March2014.pdf?ua=1   (access: 26/08/14)

[1] Euro 6/VI, US/EPA/CARB, Chinese and equivalent standards.