Air Toxics Analysis — Particularly Metals

The objective of this paper is to provide an analysis of particulate metal emissions in the USA. The analysis will identify natural and industrial sources, environmental standards, emission trends, and controls of particulate emissions. Since the majority of airborne metal emissions originate from metal industries and electric utility facilities, environmental and worker assessments of exposures as well as air pollution control research will be presented. The toxicity of ten particulate metals are characterized by inhalation exposure limits, risk-based concentrations, drinking water standards, solid waste toxicity leaching characteristics, and overall environmental hazard ranking system. The most recent biomonitoring studies have provided urinary metal concentrations for assessing background metal exposures of thirteen metals for USA populations. The increasing urinary metal concentrations and potential bioaccumulation of metals such as cadmium, mercury and selenium are discussed. Metal emissions include selenium compounds which are not assessed by OSHA, are found in coal and recycled metal materials. Selenium emissions are now greater than mercury emissions by an order of magnitude in the electric utility industry. Airborne emissions monitoring and exposure assessments of indicator metal particulate compounds are recommended for regulatory compliance and to validate the effectiveness of air pollution control technologies.