Mobile Air Monitoring Detects Hard-to-Find Air Pollution Problems
EPA scientists examine nanoparticle impacts on vehicle emissions and air pollution.
What would you do if you thought that methane might be leaking from an oil or gas well in your community?
If you were EPA researchers Dr. Eben Thoma or Dr. Gayle Hagler, you might go for a ride—in a specialized, high-tech vehicle.
Drs. Thoma and Hagler have worked with their colleagues to develop specially equipped vehicles that can detect local pockets of air pollutant emissions. These SUV-size mobile air measurement vehicles, which are now being tested, provide a way to measure air contaminants on a local scale, wherever problems are suspected.
“Mobile measurement approaches extend the spatial area you can cover,” Dr. Hagler explains. “while use of these advanced measurement techniques may be limited to short, intensive campaigns, you can learn a lot from them.” Mobile measurements of air pollution may be especially helpful in situations where there may be significant variability in local air pollution concentrations, such as nearby a large source, or where there are many small sources of air pollutants rather than one large one. One good application for mobile measurements, for example, is in the Western United States, where large numbers of oil and gas wells are spread over a wide geographic area, and where a particular well might leak methane only intermittently. EPA now has studies in progress to assess the value of using mobile measurements to detect methane emissions from oil and gas production.
Methane is not the only air pollutant that can be detected through mobile sampling, though, and oil and gas wells are not the only potential sources of pollution that can be monitored. Mobile measurements also can be used to detect near-roadway and near-rail yard pollution, for example, and to measure emissions from landfills. It also can detect a variety of other pollutants in addition to methane, including black carbon, carbon monoxide, sulfur dioxide, hydrogen sulfide, ammonia, and several classes of particulate matter.
In conducting the mobile measurements, EPA researchers ensure that the emissions from the mobile sampling vehicle do not interfere with accurate measurements. Thus, they utilize an electric vehicle when measuring pollutants that may come from a traditional vehicle's exhaust pipe, like particulate matter, but can use a standard gas-powered vehicle when measuring high levels of other pollutants, such as methane. These vehicles are equipped with a Global Positioning Systems (GPS) so that the location where the pollutants are detected can be accurately identified.
Mobile monitoring vehicles can be parked in an area for ongoing monitoring or used for occasional drive-by measurements. In communities where there are special concerns about industrial pollution, drive-by measurements could be scheduled on a regular basis. This research would serve to remind both community residents and potential polluters that EPA is addressing the community’s concerns.
Mobile monitoring does have some limitations. It focuses on a very local spatial scale (meters to kilometers) and the vehicles usually are deployed only for a relatively brief time (usually hours). Advanced applications of mobile monitoring can be labor intensive and involve complex data processing and analysis. On the other hand, some forms of mobile monitoring have great potential for wider use. Dr. Thoma explains “We are working with states, EPA Regional Offices, and industry collaborators to simplify and transfer mobile measurement technology to end users so that routine inspection uses can be realized.”
In the future, routine drive-by inspection of potential sources with automated data uplink to a public website is easily envisioned. Ultimately, technology may allow company-owned field service vehicles to be equipped with cost effective automated mobile measurement packages which look out for unexpected problems (like a leak from an underground pipe for example). Fast identification of issues leads to rapid repair, providing cost savings to the companies and improved safety and air quality.
Mobile measurements can help EPA learn more about localized emissions of air pollutants and how they affect nearby air quality. In this way, the special vehicles driven by Drs. Thoma and Hagler and their colleagues can help the Agency achieve its mission of protecting the quality of the air we breathe.