This week Air Alliance Houston begins a new monitoring project in Galena Park. Together with our partners the Environmental Integrity Project, Texas Environmental Justice Advocacy Services, and Environmental Defense Fund, we will test the passive sorbent tube monitors that the Environmental Protection Agency has proposed for use in monitoring benzene at the fenceline of oil and gas refineries.
We are assisted by the EPA’s Office of Research and Development, which has guided us through the process of developing a monitoring plan. We have also been generously offered equipment and assistance from CAMSCO, a company that produces sorbent tubes for use in monitoring the oil and gas industry. Jason Robles, CAMSCO’s president, oversaw the first deployment of our monitors in Galena Park.
Air Alliance Houston has limited experience with passive tube sampling. We undertook a small project earlier this year with students from Milby High School. The samples we took in East Houston did not exceed the air monitoring comparison value (AMCV) for benzene.
We are critical of the EPA’s proposal in the Refinery Rule to use a passive sampling method because, in our opinion, such a method doesn’t satisfy the needs of fenceline communities. We believe that people deserve real-time information about what is in their air and whether it poses a threat to them.
Passive sampling has its limitations, but it appears to be the monitoring technology that will be required at oil refinery fencelines once the refinery rule is finalized. Over the next few weeks, we will be testing these passive samplers in six locations around Galena Park.
We have also proposed to add another sampling location at the Clinton Drive ambient air monitoring site. The Clinton Drive site has monitors maintained by both the Texas Commission on Environmental Quality (TCEQ) and the City of Houston. The City generously provides us with access to the site for our monitoring work (see our recent work testing our MiniVol particulate matter monitors).
At each of our sites, we place two passive tubes. One tube will be collected and analyzed after one week, the other after two weeks. The EPA has proposed two-week sampling periods in the Refinery Rule. One of our concerns with passive sampling over long time periods is that it will average out the effect of any large but brief emissions events.
At two of our sites, we also placed another type of passive sampler, called an Organic Vapor Monitor (OVM) badge.
A passive sampler is one that simply collects a sample over time for laboratory analysis later. Passive samplers do not require pumps or other equipment to circulate air. They also do not have the capacity for on-board analysis. This means that data from a passive sampler can only be reviewed days or weeks after collection, depending on the time between collection and analysis.
Dr. Tom Stock, a Professor at UT School of Public Health and Air Alliance Houston board member, has experience using OVM Badges for passive sampling. He will compare the results of his badge samples with the results from CAMSCO’s sorbent tubes.
We will also compare our results to the data collected by nearby ambient air monitoring stations with automatic gas chromatography (Auto GC) monitors. Auto GC monitoring data is some of the better data publicly available in Houston about ambient concentrations of toxic air pollutants.
We don’t know yet what this study will tell us about passive sampling or about community exposure to toxic air pollutants. If a nearby refinery experiences a large emissions event, will that be reflected in our samples? Will the ambient concentrations of benzene in Galena Park be below the level of concern EPA has proposed for fenceline community residents?
We don’t know yet, but with the help of our partners in the nonprofit world, government, and private industry, we hope to find out. Stay tuned for further updates on this project.