The health effects of combustion-generated aerosols

Abstract The link between exposure to fine particles in the atmosphere and adverse health effects has been well-established by epidemiological studies. Most of the fine and ultrafine material of concern derives from combustion sources and is largely a mixture of elemental and organic carbon, metals, and inorganic compounds such as sulfates. When inhaled by people, the particles can be taken-up by cells in the lung. The particles can also penetrate into the circulatory system and lodge in organs such as the liver and heart. The mechanism for their impact on health is not entirely understood although the generation of reactive oxygen species such as the OH radical is a major focus. The inflammation that can be caused by these reactive species can exacerbate pre-existing ailments. Combustion conditions in mobile and stationary sources can affect the reactivity of aerosols and their ability to generate reactive oxygen species. Combustion conditions can also affect the speciation of transition metals, the morphology of particles and their composition, and their size, all parameters that may lead to adverse health effects.