Demonstration of a Continuous, Real-Time PM2.5 Chemical Speciation Monitor Based on an Aerosol Mas Spectrometer

This Small Business Innovation Research Phase II project addresses the need for improved monitoring technologies for continuous particulate mass and chemical speciation of ambient aerosols. Aerodyne Research, Inc. will develop a prototype Aerosol Chemical Speciation Monitor (ACMS) that measures ambient aerosol mass and chemical composition of non-refractory submicron aerosol particles in real-time, providing quantitative measurements of particulate ammonium, nitrate, sulfate, chloride, and organics. The ACSM will be designed to run autonomously for extended periods of time and will need no expensive post-processing analysis. The ACSM will be based on technology developed for Aerodyne¿s Aerosol Mass Spectrometer (AMS) instrument, including the inlet for efficient particle sampling and the mass spectrometric detection for quantitative mass measurements. The AMS has been successfully deployed in over twenty national and international field campaigns and has participated in several inter-comparisons with a variety of independent instruments which highlight the capability of the AMS to quantitatively measure and classify particulate inorganic (ammonium, nitrate, sulfate, chloride) and organics (primary combustion and oxidized secondary compounds) in real-time. The value of the AMS as a state-of-the-art aerosol research tool is underscored by its commercial success (thirty-four delivered to date). In The Phase I project, we 1) tested a proof of concept ACSM by inter-comparing with the AMS an with filter-based measurements of aerosol composition, 2) evaluated a prototype design for a smaller, lighter-weight vacuum chamber, and 3) quantified collection efficiencies for various particle types and sizes. Successful completion of the Phase I tasks showed that the proposed ACSM will have the sensitivity and time response to be of value to the aerosol monitoring community. In this Phase II project, we will construct a prototype ACSM and evaluate its performance for continuous monitoring applications. Specific tasks include; 1) further improvement to particle collection efficiency, 2) laboratory evaluation of the prototype ACSM, 3) development of data acquisition software, and 4) inter-comparison of the ACSM with and AMS with and AMS and with filter-based PM2.5 particulate mass and chemical speciation methods. A Phase II option will develop a dual chopper scheme for measuring particle size distributions. The ACSM will be a simple, robust, modestly-prices, aerosol chemical speciation instrument ideal for routine monitoring of local and regional air quality, for continuous emissions monitoring at hazardous waste incinerators, power plants and manufacturing facilities, and for process control monitoring. In addition, the ACSM will find applications in research studies of air pollution, health effects of particulate matter, engine design and other research areas requiring aerosol measurements.