Emissions from landscape fires affect both climate and air quality. This study uses satellite-derived fire estimates and atmospheric modelling to quantify the effects on health from fire emissions in southeast Asia from 1997 to 2006. Strong El Nino years are found to increase the incidence of fires, in addition to those caused by anthropogenic land use change, leading to an additional 200 days per year when the WHO atmospheric particle target is exceeded and increase adult mortality by 2%.