Contaminants related to coal tar include total and semi volatile organic compounds (TVOC and SVOC). TVOC compounds of concern (CoC) often include benzene, and SVOCs include Naphthalene. Coal tar vapors have a very low odor threshold of around 10 ppb. Real-time air sampling for TVOCs can give some indication of the presence of coal tar contaminants but do not identify CoCs such as Benzene.
Emilcott has provided both fixed and mobile air monitoring stations at many MGP remediation sites. These air monitoring stations typically have particulate monitors that could measure dust at a variety of particle sizes, and Photoionization Detectors (PIDs) that measure TVOC concentrations in real-time. Attached to the PID is the Greenlight Benzene Monitor, which automatically screens the TVOC vapor for benzene when levels exceed a preset threshold often down to 10 ppb. As part of this monitoring system a TO-15 air sample can be automatically initiated to collect vapors for analysis of Benzene, other VOCs and Naphthalene. All of these monitoring stations were designed to operate automatically and to be monitored remotely. Data from all the monitoring stations were integrated as part of the Greenlight Environmental Monitoring System™ with one full weather station and usually one or two added wind speed and direction sensors to accurately measure the varying wind flows impacting the site. The results are streamed live to project personnel and other stakeholders, and the air sampling system sends out alerts and notifications. The data collected by the Greenlight™ system provided evidence these radiation projects are managed safely, without negatively impacting the surrounding community.
The Greenlight perimeter air monitoring systems typically operates 10-12 hours a day, six days a week for multiple months with a >98% uptime. It can run 24/7 if needed. The system can also be operated remotely while reducing the need for full-time onsite labor - saving up to $20,000 in labor costs/month. Finally, dust threshold levels of the fixed air monitoring system could be adjusted automatically to compensate for upwind background particulate levels coming from off-site.