title: Development of an exposure system for the toxicological evaluation of particles derived from coal-fired power plants.
abstract: To investigate the toxicity of particles originating from coal-fired power plants it is necessary to consider the effects of both primary particles and secondary components formed in the air through atmospheric reactions. This report describes a new exposure system that can be used to expose animals to both directly emitted particles and to secondary particles. The system consists of three main components. The first is a sampling system to continuously collect and dilute power plant stack emissions. The second is a reaction laboratory that contains reaction chambers to simulate atmospheric reactions. The following atmospheric reactions were simulated: (1) the oxidation of sulfur dioxide to form sulfuric acid, (2) the neutralization of sulfuric acid by ammonia, and (3) the reaction of alpha-pinene with ozone to form secondary organic aerosol. Using these chambers with the diluted emissions, different typical atmospheric scenarios can be simulated. The final component is a mobile toxicology laboratory where animals are exposed to the resulting test aerosols. We report here the characteristics of the test aerosol exposures obtained at a coal-fired electric power plant. Particle exposures were characterized for concentrations of mass, elements, elemental carbon, organic species, inorganic ions, strong acidity, particle number, and size distributions. Mass concentrations ranged from a few micrograms per cubic meter for a scenario of primary emissions only, to about 250 microg m(-3) for the most complex scenario. We show that the different scenarios produced a large variation in the composition of the test aerosol, thus potentially changing the toxicity of the emissions.
authors.affiliation: Exposure, Epidemiology, and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02215, USA. pruiz@hsph.harvard.edu
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Ruiz
authors.forename: Tarun
authors.initials: T
authors.lastname: Gupta
authors.forename: Choong-Min
authors.initials: CM
authors.lastname: Kang
authors.forename: Joy E
authors.initials: JE
authors.lastname: Lawrence
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Ferguson
authors.forename: Jack M
authors.initials: JM
authors.lastname: Wolfson
authors.forename: Annette C
authors.initials: AC
authors.lastname: Rohr
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D000818:Animals; D001273:Atmosphere Exposure Chambers; D003031:Coal / Q000032:analysis* / Q000633:toxicity; D004781:Environmental Exposure / Q000032:analysis*; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000633:toxicity; D011210:Power Plants
chemical_list: D000393:Air Pollutants; D003031:Coal; D052638:Particulate Matter