Household air pollution created by using wood, coal and other solid fuels for cooking and heating homes is a leading cause of respiratory and cardiovascular diseases worldwide, and causes more than 4 million premature deaths each year, according to the World Health Organization (WHO). To tackle this global health problem, the National Institutes of Health (NIH), with partial support through a grant from the Bill & Melinda Gates Foundation, is funding a $30.5 million, multi-country trial to determine if using a widely available, clean, alternative cooking fuel significantly reduces deaths and illnesses, especially in women and children who suffer the greatest exposure. This is the first large-scale trial to investigate whether home use of cookstoves that run on liquefied petroleum gas (LPG) improve air quality sufficiently to provide measurable health benefits and can be effectively adopted in real world situations.