The Nickel Report

In recent years there has been an explosion in the availability of small, low cost, hand held (or drone mounted) air quality monitoring devices or air sensors. Although the most likely near term applications may be community groups seeking information on potential industrial impacts, even individual consumers may have use for such devices to monitor the quality of indoor air. The biggest hurdle to the effectiveness, and eventual integration into the realm of regulatory compliance, of these devices is the lack accepted standards for evaluating the quality of the data they produce. What role will EPA play in that?

At the September meeting of the Clean Air Act Advisory Committee (CAAAC), EPA staff discussed a number of initiatives on the use of indoor and outdoor air sensors and sought feedback from CAAAC members. To say there is a lot going on is quite an understatement. In June, EPA had over 700 attendees at its workshop and webinar soliciting input from stakeholders on non-regulatory performance targets for sensors measuring fine particulate matter (PM2.5) and ozone. And just two weeks before the CAAAC meeting, several dozen EPA staff attended UC Davis Air Quality Research Center’s first “Air Sensors International Conference” to discuss similar issues. The University of California is an obvious location for such research given that state’s legislation requiring additional refinery air monitoring under SCAQMD Rule 1180 and BAAQMD Rule 12-15, and the more comprehensive Community Air Protection Program (CAPP) now being implemented by CARB under Assembly Bill 617.

Of course, EPA’s work on these issues is not new. Back in 2014, EPA staff produced what they call the “Air Sensor Guidebook” to help individuals identify the best technology for a specific application, use the technology properly, and understand the data they collect. EPA/600/R-14/159 (June 2014). With little progress since then establishing uniform standards to address data quality, interpretation, and management, EPA may be on the verge of taking an even greater leadership role. According to the CAAAC presentation, EPA is working on a policy memorandum to address questions from state and local agencies on the use of air sensor data, including its use in NAAQS compliance. Hopefully this memorandum will allay fears that the data collected will be misunderstood and/or misused under regulatory programs. On the technical side, EPA is considering development of a voluntary certification program for air sensors. As a starting point, EPA has produced a report evaluating peer-reviewed literature and other sources of information on a variety of sensors to identify criteria needed to ensure that data collected are appropriate for the intended application. EPA/600/R-18/324 (September 2018). EPA staff also are monitoring (and likely participating in) work conducted by the American Society for Testing and Material International (ASTM), which has established a workgroup to draft a “Test Method for Performance Evaluation of Ambient Air Quality Sensors and Other Sensor-based Instruments” (ASTM WK64899). ASTM is a consensus-based standards development organization. If you are interested in the topic you can become a member (I am one) and contribute to the effort.

As EPA’s presentations made clear, the potential reach of these air sensors is huge. Most of us did not envision in the early 1990s that in this decade nearly every teenager and adult would carry their own phone with their own phone number. It is not unreasonable to think that one day we all may have air sensors in our homes and offices. By way of example, the University of Utah’s School of Computing recently conducted research to assess how people respond to information from PM sensors placed in their homes to measure the impacts of everyday influences like cooking, smoking, cleaning, and using candles. If you can believe the sensors, such activities can have a big impact on air quality and using the sensors could help us all better manage our health. Being a bit of a gadget addict myself, I suspect there is one of these in my future. I’d feel better about that if I knew the sensors were accurate.