Current instruments for monitoring particulate matter (PM) are inadequate in their ability to determine aerosol size or size distributions. Operation of existing systems requires a good understanding of sensor design. For example, variations in ambient conditions may necessitate either new calibration or measurements to be computationally corrected to ensure accurate particle size determination. This required level of expertise limits wide deployment of existing systems. As a result, NAL Research Corporation proposes the development of a portable real-time aerosol-sizer based on a pair of miniature laser-Doppler velocimeters (LDVs) designed with diode lasers and avalanche photodiodes. Particle aerodynamic diameter can be directly obtained from the measured velocity gradient. The use of miniature LDVs enables the proposed instrument to be simple, compact and lightweight. Furthermore, the sensor will not need calibration contrary to the time-of-flight (TOF) aerodynamic particle sizer (APS). Minimal technical competence will be expected for operation in a wide variety of conditions for emissions characterization and monitoring. These factors combine to ensure the system is inexpensive.Potential Commercial ApplicationsNAL Research anticipates significant opportunities related to EPA mandated aerosol characterization and monitoring efforts. As directed by the National Research Council, characterization of emissions from stationary and mobile sources over the next decade will provide significant commercial markets for the inexpensive and accurate sensor herein proposed. According to the EPA monitoring regulations set forth in 40 CFR 58, particulate matter monitoring will be required in large metropolitan areas and many community-oriented sites across the United States. Furthermore, the EPA and OSHA organizations regulate air quality within and around closed and open pit mines. Mining operations exist throughout the United States and around the world. Mines tend to be large, complex sites wherein multitudes of sensors may be needed for adequate monitoring. This represents a potentially large commercialization opportunity worldwide. The medical community is another important market for the proposed particle sizer. Aerosol sizing is important component of toxicological studies of effects of aerosols on life, including humans. Monitoring of indoor air quality as part of study of sick building phenomenon requires improved understanding of PM, both natural and anthropogenic. These and other aspects of ongoing research in the medical community represent significant commercialization opportunities for the proposed particle sizer.
