Ultra-Sensitive Detection of Air Toxics Using Incoherent Cavity Ringdown Spectroscopy

In this SBIR Phase I effort, Los Gatos Research (LGR) proposes to design, build and test a novel Incoherent Cavity Ring Dow Spectroscopy (iCRDS) gas analyzer operating I the mid-infrared (MIR) region for the continuous, real-time, on-site detection of multiple air toxics in ambient air. Specific applications include EPA priorities such as: air quality monitoring at remediation sites, vapor intrusion from contaminated ground water plumes, quantification and monitoring of sick building syndrome, in-stack stationary monitoring, and mobile platform monitoring of large sources. The analyzer will have sensitivity, precision and accuracy similar to portable Gas Chromatography/Mass Spectroscopy (GC/MS) for a 1.7– 10x lower cost of ownership in the first year alone. Sensitivity and accuracy will be 500 – 1000x better than long-path, open-path Fourier Transform Infrared (FTIR) spectroscopy. Additionally, the analyzer will operate without the substantial drawbacks of GC/MS, such as expensive and laborious sample collection, expensive consumables, frequent calibration by a skilled operator, and lengthy delays in data reporting. The analyzer will employ iCRDS, a technique that has been shown to be extraordinarily rugged through numerous field deployments and successful commercialization in the near-infrared. Recent advances in widely-tunable, external-cavity quantum cascade lasers (EC-QCL) allows the extension of iCRDS into the MIR region, where the simultaneous measurements of multiple, large organic compounds is possible, making the method very attractive for measuring ambient concentrations of EPA-relevant air toxic compounds, The combination of a widely tunable EC-QCL and iCRDS will allow the sensitive, precise and accurate measurement of indoor and/or outdoor ambient air without preconcentration of the sampled air stream. The proposed research will establish the feasibility of utilizing LGR’s iCRDS technology for the sensitive detection multiple air toxic compound in ambient air. A mid -infrared laser-based gas analyzer has significant commercial air quality monitoring applications. Through a series of strategic partnerships, LGR is developing a suite of analytical instrumentation to measure trace gases for ambient air quality monitoring, industrial process control, petrochemical applications and medical diagnostics. The proposed work is essential to demonstrating mid-infrared iCRDS and its application to air monitoring.