Almost half the world’s population, around 3000 million people, still rely on biomass fuel for their everyday household energy needs Estimates suggest that in more than 30 countries, wood provides more than 70% of the energy needs, and in 13 countries it is over 90%. In these poor rural and urban homes, biomass fuels and coal are typically burnt in open fires or poorly functioning stoves, often indoors, with inadequate ventilation for the smoke. This leads to very high levels of pollution in the homes where especially women and young children are exposed on a daily basis. Smoke from these fuels contains many health damaging pollutants, including particulates, carbon monoxide, nitrogen oxides, benzene, and many others. Together, these pollutants are known to be capable of irritating the airways and lungs, reducing the resistance to infection, and increasing the risk of cancer.