ENV-06-142 Continuous Fence line Air Monitoring for Benzene Using an Automated-Gas Chromatograph

Description:

In 1997, a regulatory ambient air monitoring station was established in a neighborhood adjacent to several Gulf Coast refineries. Subsequent 24-hour time-integrated VOC canister sampling found that concentrations of benzene exceeded the State guidelines. While this type of sampling was able to determine guidelines were being exceeded, the frequency and time-resolution of sampling were not sufficient to identify the primary sources of benzene emissions. Surrounding industry joined together to conduct supplemental air monitoring in order to identify benzene emissions sources affecting concentrations measured at the State monitoring site. A two-phase monitoring approach was proposed and implemented. First, a benzene air monitoring survey was conducted within and along plant boundaries using passive dosimeters and portable handheld instruments. Next, a real-time automated gas chromatograph (auto-GC), capable of measuring sub-part-per-billion (ppb) levels of benzene, was installed adjacent to the State’s existing monitoring site. Monitoring conducted during the survey was able to discover previously unidentified benzene source areas, while the ongoing auto-GC monitoring effort has been instrumental in tracking the progress of benzene emission reduction efforts, identifying benzene source areas, and providing industry members with near real-time notification when unexpectedly high benzene concentrations occur. Members from the surrounding community, industry representatives, and URS personnel meet on a monthly basis in order to discuss monitoring results and progress being made in emission reductions. These meetings have provided industry representatives with a forum where information can be released to the public in a proactive and controlled manner. Additionally, these meetings have helped facilitate a constructive dialogue between local industry and the community, fostering improved public relations.