Air Pollution as a Climate Forcing: A Workshop
Day 4 Presentations
Understanding the Effects of Climate-relevant Components of the Air Pollution Mixture — The Carbon Particle Fraction
Daniel S. Greenbaum
Health Effects Institute, Charlestown Navy Yard, Boston, MA, U.S.A.
You may download a MS PowerPoint version (780 MB) of this presentation.
Air pollution is a complex mixture of gases and aerosol particles, with many of the components having been shown to cause or contribute to respiratory, cardiac, neurotoxic, and other health effects. Recent global climate change research (Hansen 2001) has found that these various components of air pollution also have varying effects on global climate. This paper introduces two sessions to (a) review the state of current knowledge of the health effects of different components of particulate matter, and of key gases, and (b) describe efforts to estimate the magnitude of public health impacts of these pollutants in developing countries, and on a global scale.
Among the air pollutants, public health attention has focussed in the last decade on the health effects of fine particles (PM2.5). A substantial body of short term epidemiology, and two major cohort studies, have found consistent relationships between exposure to PM and premature mortality. Within the particle mixture, carbon soot particles, which are emitted primarily from on- and off-road mobile sources of pollution and the burning of wood and other biomass, have been associated with increased morbidity (e.g. hospitalization) and premature mortality from cardiopulmonary disease and cancer. The mechanism by which these carbon particles might cause these effects include direct effects of the carbon particles themselves (for example in the form of ultrafine particles), as well as as carriers of other toxic components (for example metals and organic chemicals such as PAHs) into the deep lung. This paper reviews the data for these health effects to date, and identifies areas needing continuing research.