Acrolein Monitor Using Quantum Cascade Laser Infrared Absorption

Acrolein has been identified by the U.S. Clean Air Act as a hazardous air pollutant because of its adverse health effect, particularly on respiratory systems. There are both anthropogenic and natural sources of acrolein in the environment. Acrolein is produced by combustion sources (e.g., vehicle exhaust, prescribed agricultural burning, cigarette smoke) and industrial sources, including manufacturing facilities of wood products. There is, however, limited data quantifying the emissions of acrolein from these sources. There also are few reports of ambient levels because of the measurement limitations. There is a need for air quality instrumentation for acrolein and other toxic air pollutants for routine air quality monitoring in urban areas for health effect assessment and at specific sites for source assessment studies. The U.S. Environmental Protection Agency Region 10 has identified as a priority issue the development of a measurement technique for monitoring acrolein. Aerodyne Research, Inc., proposes to develop a fast-response, novel, quantum-cascade laser system based on tunable infrared laser differential adsorption spectroscopy (TILDAS). The diversity of sources and the relatively high reactivity of acrolein require a highly sensitive, easily portable, and fast-response measurement technique. The proposed acrolein monitor will meet these requirements, achieving sensitivities both in the parts-per-billion range for source monitoring and parts-per-trillion range for ambient monitoring. The objective of this Phase I research and development effort is to determine the feasibility of a real-time, mid-infrared TILDAS instrument to monitor acrolein. Aerodyne will evaluate potential infrared spectral regions to determine the optimum region for acrolein monitoring. Aerodyne also will investigate background suppression techniques that are critical to achieving low detection limit. The Phase II instrument design will be identified in Phase I. The anticipated result of Aerodyne’s approach is a robust, sensitive, real-time monitor of acrolein. It will be capable of long-term operation in the field or laboratory with minimal maintenance. There is a need for commercially available air quality instrumentation for acrolein and other toxic air pollutants. The infrared laser detection technique to be developed in this proposal will have wide commercial applications both for routine air quality monitoring and for source assessment of hazardous air pollutants.