Health Impact Assessment (HIA)

Optimizing health in transport and climate change measures - new report identifies key strategies

DURBAN - Rapid transit and safe cycling/walking networks are good for both health and climate – and climate experts should consider more systematically how these strategies can reduce CO2 emissions in the transport sector, one of the world's major contributors to climate change, says a new WHO report.

The new report, Health co-benefits of climate change mitigation - Transport sector was released 6 December, 2011 during the United Nations Framework on Climate Change Conference of the Parties (COP-17).

The report reviewed over 300 studies on health outcomes from different types of land transport systems in a "scoping exercise" designed to identify those mitigation measures most closely associated with specific health co-benefits or risks.

The review is the latest product of WHO's Health in the Green Economy initiative, which is considering available evidence on health impacts from climate mitigation strategies for key economic sectors, as reviewed by the UN's Intergovernmental Panel on Climate Change (Climate Change, 2007).

The new WHO report was launched at an official COP-17 Side Event on "Health and Development in Climate Change Mitigation and Adaptation," convened by the Government of South Africa, the United Kingdom of Great Britain and Northern Ireland, and WHO. The report was also the focus of a press briefing, involving high-level officials from South Africa's Department of Health and Department of Transport, as well as WHO.

The IPCC's global assessment of mitigation options for the transport sector places the greatest emphasis on the mitigation potential of improving carbon efficiencies for private vehicles and fuels.

In contrast, the WHO review found a stronger, and more positive, association with health benefits from rapid transit and dedicated walking/cycling systems – measures which are covered by IPCC, but not as systematically and with little note of health issues.

MP Jeremy Cronin, Dr Carlos Dora and Dr Ramphalane Morewane
MP Jeremy Cronin, Dr Carlos Dora and Dr Ramphalane Morewane in Durban

"We have looked at the IPCC assessment through the lens of public health and come up with quite a different reading," said Dr Carlos Dora of WHO's Department of Public Health and Environment, in the briefing to journalists.

"Public/rapid transport and safe cycling and walking are the prototype of a transport system that is good for health; it so happens that these are good for climate too."

A large and growing body of literature finds such systems are strongly associated with more healthy physical activity, lower urban air pollution risks, and lower rates of traffic injury among transit users and pedestrians and cyclists on dedicated networks, said Dora, citing findings in the report.

Land use systems that emphasize more compact cities, and mixed use development of commercial and residential areas, along with amenities for walking and cycling, also are strongly associated with better health as well as greater health equity because they allow groups such as children, women, older people, disabled, and those without cars to move around more safely and easily.

Senior officials from South Africa's Department of Transport and Department of Health, said that the report places pressing health, development and climate issues in a fresh, intersectoral perspective.

Carlos Dora and Jeremy Cronin
MP Jeremy Cronin and Dr Carlos Dora in Durban

"I am really pleased that we are making the triangular connection between health, equity and climate justice," said MP Jeremy Cronin, South Africa's Deputy Minister of Transport. "In South Africa more than 15 000 people are killed on our roads every year, 40% of those are pedestrians, and significant numbers are children of the poor working classes," Cronin observed. "The numbers of road traffic fatalities are greater than that of malaria, and steadily approaching that of HIV. This tragedy is increasing, partially due to …investments in freeways and roads rather than public transport. "But it is preventable, given major interventions. So we really welcome the publication, as it gives us a better understanding of what we are facing in South Africa on the transport and health front."

Dr Ramphelane Morewane, Chief Director of Regional Services in South Africa's Department of Health, told reporters that the report created opportunities for health and transport sectors to work together.

"Transport is not only an enabler in terms of access to health care, but we now recognize that there are other modes of transport that have greater health benefits, such as walking and cycling," said Morewane.

The case studies of transport and health issues at country level, including a review of South Africa's own challenges and recent progress in promoting rail, bus rapid transit and non-motorized transport systems, is another positive feature of the WHO report, Morewane noted.

"We welcome that there is a case study that comes from South Africa, so it is not something that has been 'sucked out of a thumb'," he observed.

The report looked at studies of health outcomes in association with different types of transport investments; transport system use; and land use patterns, and identifying some of the following health-transport linkages:

  • increased physical activity among people who walk and cycle regularly as part of their transport routine. Some studies also cited evidence of lower mortality or lower disease incidence from such physical activity, which can help prevent heart disease, some cancers, type 2 diabetes, and some other obesity-related risks;
  • reduced risks of premature mortality among people who cycle to work in some major urban studies, even after injury risks are considered; relative risk of mortality was as much as 20-30% lower in studies tracking large populations over time in both Copenhagen and Shanghai;
  • lower urban air pollution concentrations and exposures in cities and transport systems that rely heavily upon clean rapid transit and non-motorized transport;
  • lower rates of traffic injury in cities with comparatively less travel by private vehicles and more via transit/non-motorized modes; lower injury rates in cycle and pedestrian-friendly areas such as low-speed zones; and lower injury rates among transit users generally;
  • Reduced noise stress in neighbourhoods where there is a strong emphasis on traffic calming, traffic diversion, and non-motorized transport.

Strong rapid transit, cycling and walking networks also were found to yield added health benefits for vulnerable groups that typically have less access to private vehicles, including: children/teens, the elderly, women, people with disabilities, and lower wage-earners.

"Taken together, these groups comprise most of the world's population," notes Dora. "So, in fact, many forms of low-carbon transport can provide many benefits to most people, in countries at different development stages.

Certain kinds of climate mitigation measures can also create risks for health, Dora noted. One key finding of the report was that making diesel vehicles a central feature of climate mitigation could generate new health risks from air pollution exposures.

While diesel vehicles are often more fuel-efficient, they also emit comparatively higher levels of small particulates than conventional gasoline engines. Higher ambient average concentrations of small particulates (PM10, PM2.5) have been linked to comparatively higher rates of premature mortality in many epidemiological studies and WHO Air Quality Guidelines (2005) recommend guideline values for average small particulate concentrations that are far lower than those common in many developing cities today.

"Many kinds of climate and transport measures can yield large, immediate, benefits for health, but some climate measures may be very bad for health, for example diesel engines," said Dora. "At the local level, more reliance on diesel can increase relative risks of respiratory and heart disease. Also, better fuels don’t do anything for noise, for physical activity and for safety risks. Public transport and safe cycling and walking do help reduce these risks, too."