RealTime, Ultrasensitive Measurement of Process Emissions for Pollution PreventionEPA Grant Number: R826730
Title: RealTime, Ultrasensitive Measurement of Process Emissions for Pollution Prevention
Investigators: Senkan, Selim M.
Institution: University of California - Los Angeles
EPA Project Officer: Karn, Barbara
Project Period: October 1, 1998 through September 30, 2001
Project Amount: $350,000
RFA: Technology for a Sustainable Environment (1998) RFA Text | Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
Description:Real time measurement of process emissions is important for undertaking rational pollution prevention and risk reduction strategies. The selective measurement of gaseous species, usually at trace levels, in a complex background mixture is of particular concern because many toxic pollutants are present at parts per trillion (ppt) to parts per million (ppm) levels in process effluents. Consequently there is a growing need for the development of highly sensitive and selective techniques to continuously monitor the concentrations of a broad range of compounds. In this proposal we would like to exploit recent advances made in resonance enhanced multiphoton ionization (REMPI) and time of flight (TOF) mass spectrometry (MS) for the development of real time and ultrasensitive detection techniques to monitor a wide range of molecules in the gas phase. An important and challenging chemical reaction process where the REMPI-TOF/MS should have a major impact is in combustion. This is because combustion of fossil fuels is a highly complex, exothermic and high temperature reaction process which is associated with the production of trace levels of aromatics, polycyclic aromatic hydrocarbons (PAH), dioxins and their derivatives, some of which are highly toxic. We believe the development of the REMPI-TOF/MS technology to monitor emissions in a harsh combustion environment should readily be adaptable to chemical manufacturing processes, such as catalytic cracking of petroleum, that generally operate under milder conditions. The proposed program has two specific objectives: 1. Molecular spectroscopy, excited state dynamics and REMPI-TOF/MS detection of large PAH and 2. REMPI-TOF/MS measurements of PAH concentration profiles in laboratory flames. Our program have already received significant industry interest and support as noted in the attached letter of endorsement from Chevron.
Expected Results:The proposed program, when completed, will provide information on two fronts: First, fundamental REMPI spectra for large PAH that are of significant health concern, such as benzo(a)pyrene and dibenz(a,h)anthracene, will be generated for use in the development of optimal REMPI strategies for the real time detection of these species. Second, the applicability and limitations of REMPI-TOF/MS for the real time measurements of large PAH in hot combustion gases will be established.
Improvement in Risk Assessment or Risk Management: The development of the REMPI- TOF/MS technology should accelerate the progress in pollution prevention on several fronts. First, because real time ultrasensitive measurements would be a useful risk screening tool, it should help in the development of new products and processes that are less polluting in the first place. Second, the development of this technology should enable the implementation of active control methods to minimize the formation and emission of trace pollutants from existing processes.