This research has demonstrated that an ethylene-oxide monitor with ultra-low limit of detection based on sensitive and selective optical measurement technology is feasible and will meet the needs for an ambient monitor. The exposure limits for ethylene oxide (EtO) in ambient air have been recently reduced to 11 parts per trillion (long-term, 1/10,000 risk level). Monitoring EtO at this low concentration will require advanced technology. Current techniques require sample trapping and preconcentration to achieve the specified limit of detection (LoD), however the method suffers from losses at low concentration and is susceptible to cross interference from other gaseous volatile organic carbon species. The optical technology demonstrated project is direct, sensitive, and specific for EtO. Our method does not collect, preconcentrate, or require any other sample preparation. The monitor achieved relative and absolute uncertainties better than the 11 ppt exposure limit in <2 minutes of measurement time. The speed of this measurement is another significant advancement over the approaches that use sample collection. Building on the Phase I results, we will develop a field ready EtO that can be utilized for ambient air monitoring to assess public health risk, and to industrial fenceline/facility detection to identify EtO emission sources. The research goals of the Phase II program are: improve the zeroing system to eliminate consumables, expand the number of species that are ruled out as interferences, develop a field-ready quantitative calibration system at relevant concentrations, and investigate an alternative spectral region. Finally, the Phase II improvements will be demonstrated in real-world field measurements. The end users of this technology will primarily be state and federal EPA offices and other local and regional environmental agencies, as well as industrial EtO producers and consumers aiming to comply with regulations. Our continuing discussions with researchers at state agencies (CA and TX) indicate intense interest in our technology from that sector, with initial sales on the 1-3 year timescale. We expect the industrial market to grow due to an evolving regulatory landscape, with sales occurring on the 5-10 year timescale. Upon completion of the Phase II work, we will have researched and demonstrated all elements needed for a state of the art commercial EtO monitor that is direct, online, accurate, sensitive and selective. It will operate without consumables and be applicable to multiple measurement contexts, including ambient air, facility fenceline and industrial emissions monitoring innovative about the technology, technical feasibility, results of Phase I, commercial application(s)/end users, size of the potential market, performance compared to current technologies, and environmental benefits
