Chemical Composition Measurement of Atmospheric Aerosols in Real-Time

This Phase I SBIR project addresses the need for an instrument to measure the chemical composition of size-classified ambient aerosols in real time. In particular, this instrument will require minimal user interaction and be adaptable to airborne measurements. The proposed measurements would help us understand how aerosol particles are processed in the atmosphere by chemical reactions and by clouds, and how hygroscopic particle properties change as the particles age. These results are critical for an understanding of the ongoing climate change. To this end, a novel technique is proposed that performs mass spectrometry on the ions of various chemical species released from the aerosol. It automates the process by electrostatically depositing the particles on a thin rod, washing them away with a solvent and electrospraying the solution to obtain ions of the soluble compounds. This process results in soft ionization of various molecules with minimal fragmentation. Besides being valuable for atmospheric research, our proposed instrument would be worthwhile in monitoring air quality as regulated by EPA. It would be superior to existing instruments due to analysis in near real-time, automation, portability, and ability to measure large and fragile molecules. The proposed instrumentation would also make it easier to monitor particulate matter in occupational environments like mines, powder processing, and semiconductor manufacturing, as well as areas affected by forest fires. Keywords: aerosol instrument, chemical composition, real-time measurement Summary for the Members of Congress: This project brings together a team of leading aerosol experts to develop a cutting-edge technology for investigating the chemistry of airborne particles, which is critical for the understanding of climate change. The resulting instrument will also be an advanced tool for monitoring and controlling air pollution.