Greener investments in transport, housing and household energy policies can help prevent significant cardiovascular and chronic respiratory disease, obesity-related conditions and cancers.

These are among the findings of a new global World Health Organization series that looks systematically, for the first time ever, at the health 'co-benefits' of investments in climate change mitigation reviewed by the Intergovernmental Panel on Climate Change (IPCC).

Overall, sustainable development policies in housing, transport, and household energy may benefit health right away - even if the broader climate gains are realized over years or decades.

The new WHO series, Health in the Green Economy, finds that the health sector needs to become stronger advocates for those green economic investments that prevent disease at the outset.

On the other hand, climate experts, including the IPCC, which is the leading international body for the assessment of climate change, need to put health at the center of mitigation efforts, the series also recommends.

"Some climate change mitigation measures yield broader health gains than others," says Dr Maria Neira, director of WHO's Department of Public Health and Environment. "Potential health benefits -- as well as certain risks -- should be considered more systematically in climate assessments. And if that is done, we can identify strategies that are truly win-win."

In the case of more climate-friendly housing, the immediate savings in health care costs from home energy-efficiencies and home insulation programmes may be so large that they could rapidly repay investments made - even if savings in greenhouse gas emissions take longer to realize. The report on housing, the first full report of the series to be issued, was released on 14 June at the annual meeting of the Global Health Council in Washington, DC.

Many forms of asthma and allergies, as well as heart disease and strokes related to increasingly intense heat waves and cold spells could be addressed by more climate-friendly housing measures, the report finds.

However more weather-tight housing can introduce some new health risks - unless adequate fresh air ventilation is assured. The report also found that not enough attention is being paid to the housing risks of rapidly growing developing cities, and how more climate-friendly housing and urban design could improve the health of the poor, as well as reduce climate change.

WHO's Health in the Green Economy series is looking at climate change mitigation and "green growth" strategies in five economic sectors: transport, housing, health care facilities, household energy in developing countries, and agriculture.

As other examples of "best buys" for health, initial findings from reviews of other sectors identify considerable evidence that:

- Investments in, and use of, safe walking/cycling and public transport networks are strongly associated with more healthy physical activity, lower rates of premature mortality, and less obesity. However, the last IPCC report focuses on better fuels and engines as mitigation measures, giving little attention to the much wider benefits offered by policies that favour walking cycling and public transport. This neglects the broader range of health and social benefits that can be derived from adopting more sustainable transport.

- Deaths of more than 1 million people annually from chronic obstructive pulmonary disease (COPD) due to indoor air pollution from traditional biomass and coal-fired stoves are largely avoidable with more energy efficient stoves. An estimated 15% of this burden in Latin American and Sub-Saharan African could potentially be averted in less than a decade if more advanced biomass or biogas stoves were introduced at a pace compatible with UN targets for achieving universal access to modern energy services by the year 2030.

"This series explains why green housing and home energy, transport, and urban environments can improve our health - and why the health sector can prevent much disease, at very little cost, by advocating for healthier investments in some key sectors," says WHO's Dr Carlos Dora, an epidemiologist and coordinator of the series.

"The bottom line is that people can try to practice healthy diets and healthy lifestyles. But we also need a supportive environment," says Dr Luiz Galvao, Manager, Sustainable Development and Environmental Health, of the Pan American Health Organization/WHO.

"In our busy lives, not everyone has time or money to go to the gym. But if we live in a healthy house and in a city where we can easily and safely walk or cycle to work, and get regular exercise just by moving around outdoors, this can make an enormous difference to our lifestyle and our overall health."

Currently, the health care sector is beset with soaring health care costs for cardiovascular disease, hypertension, stroke, cancers and a range of other obesity and non-communicable disease conditions.

And 80% of such chronic disease is now occurring in lower income countries, where urban growth is driving rapid slum expansion, soaring traffic volumes, air and water pollution and rates of traffic injury.

"People really cannot make healthy lifestyle choices - unless they have a healthier environment," Dora observes. "So we, as health professionals, need to promote basic environmental measures that cost the health sector very little, and can avoid many subsequent years of treatment. And these health savings an be captured immediately - while the climate benefits accumulate for the future."

Other key findings:

- About 4% of the annual ischaemic heart disease (IHD) disease burden among African and Latin American adults over 30 could be avoided by 2020 with introduction of more advanced biomass or biogas stoves in pace with the same UN universal energy access target. Here, too, many health benefits will be realized over a course of several years, due to the chronic nature of the disease.

- By 2020, close to 17% of the annual pneumonia deaths among African and Latin American children under the age of five could be avoided, if more advanced biomass or biogas stoves were introduced at a pace compatible with the UN target for universal energy access.

- Emissions of climate change pollutants also could potentially be reduced by as much as a billion tonnes of CO2-eq between 2010 and 2020 as a result of the uptake of new, very-low emission biomass stoves or other clean fuel technologies in sub-Saharan Africa and Latin America at a pace compatible with universal energy access goals. This translates into distribution of about 13.5 million stoves a year between 2010-2020.