Recently a gas production station in New Zealand experienced regular issues: monthly average benzene concentrations at the boundary exceeded the national monthly guideline value of 1 ppbv. This issue was identified using traditional sampling with thermal desorption tubes, followed by thermal desorption-GC/MS analysis. However, the monthly averages could not provide the insight that production engineers required to design and implement a solution.
Better time resolution for benzene was required, so Syft Technologies was engaged. We deployed a Syft Voice200 instrument in a van for one month at the boundary of the industrial facility. The instrument provided direct analysis of benzene, toluene, ethylbenzene, and xylene emissions at sub-ppbv levels with one-minute time resolution.
The figure shows one week of monitoring at the eastern boundary as an example. Transient benzene concentrations exceed 70 ppbv when winds have a westerly component. These regular peaks correspond to release of pressure from a condensate tank, and account for the high average values at the boundary. Armed with this data, engineers were able to tackle the engineering issues and design a solution to prevent the exceedances.