High Sensitivity SO2 Monitor using Quantum Cascade Laser IR Absorption

SO2 is an important ubiquitous aerosol precursor with anthropogenic, biogenic and geogenic sources. The sulfate aerosol produced from atmospheric oxidation of SO2 has a negative radiative forcing component that is highly uncertain due to its direct and indirect effects. Due to its potency as a remote clean atmosphere aerosol precursor and its capability to modify cloud properties, SO2 is a short lived greenhouse compound. Direct measurements of SO2 that are accurate, interference free, sensitive and rapid are needed to support particulate sulfate and aerosol instrumentation. The Phase I demonstration of the approach will lead to a Phase II instrument that will be further improved and field tested. The instrument is a major advancement over current commercial instrument capabilities, made possible by recent advances in technology using infrared quantum cascade lasers. In dedicated measurement campaigns and at remote clean air monitoring stations this technology will yield a sensitive, selective measurement of this important aerosol precursor. Commercial Applications and Other Benefits: The proposed instrument will provide the capability to measure atmospheric abundances of SO2 in real time in order to better asses H2SO4 production and subsequent aerosol or cloud modification. Improved understanding of aerosol and cloud properties will improve our understanding of global climate change and help evaluate the mitigation strategies. There is a worldwide market for such measurement systems in the environmental and aerosol research communities.