Low-Cost Air Sensors: The Risks and the Rewards
By Joel Creswell, Ph.D.
Picture a future in which every device you interact with is connected to the internet and communicating in real time. Your thermostat notices that you’re not home and offers to turn down the heat. Your refrigerator tells you what food is going to go bad soon and pulls up recipes to help you cook it. Your kitchen faucet monitors the safety of your drinking water, and every street lamp can tell you how clean the air is.
Today, this future is part fantasy, but it’s not hard to imagine all of these ideas becoming reality based on current or rapidly-evolving technology.
Reliable information can help us make better decisions. But what if the information we get from sensors is unreliable? What if your kitchen faucet monitor tells you your water is unsafe, leading you to spend hundreds of dollars on a new filter, only to learn that the monitor was wrong? What if the air sensor on your street lamp says the air is dangerous to breathe, causing you to keep your kids inside, when actually, everything was fine? Unreliable sensors can cause unnecessary concern, wasted money, or unwarranted complacency.
The market for environmental sensors is exploding,1 and many sensor users have to determine for themselves which devices are reliable. If you have access to a laboratory, you can compare a new sensor to a proven method to make sure it works. But most consumers don’t have that kind of access and even many environmental professionals don’t have the time or resources to validate every new sensor they buy. This is why groups like EPA’s National Exposure Research Laboratory and California’s South Coast Air Quality Management District have started air sensor evaluation programs. These groups test new sensors and publish performance reports online to help guide sensor users.
Independent sensor testing fills a critical knowledge gap and has become so popular that existing testing labs are having trouble keeping up with demand. EPA is considering ways to scale up the availability of sensor testing, including a network of labs with standardized protocols and reporting.
In March, I presented an outline of an independent sensor evaluation network in a session on air sensors and citizen science at the National Association of Clean Air Agencies’ Communicating Air Quality conference. My presentation emphasized that sensor technologies have the potential to revolutionize environmental monitoring, but only once their reliability is demonstrated. Many of the state agencies at the conference were eager to see a sensor evaluation network established – several told me stories of phone calls from concerned citizens who had purchased untested or unreliable air sensors and were concerned about the dangerous air quality the sensors were (erroneously) indicating. EPA, State and local environmental agencies, and the public need good information on sensor performance to eliminate the confusion caused by unreliable data and harness these powerful new tools to usher in a new era of environmental protection and decision making.
I’m excited about the proliferation of sensors. I already use my phone to count my steps every day, I have a smart thermostat in my house, and I wish I had a fridge that told me when my food was going to go bad. I love new technology that works well. But when I try something that doesn’t work well, like my old smoke alarm that would go off every time I turned on the oven, I get frustrated and stop using it. My solution to the smoke alarm problem? I took the battery out, putting myself at risk if my house ever caught fire. EPA is working to make sure we don’t all put ourselves at risk, by ensuring that we have good data on how well air sensors perform.
(1) Gainer, K. Environmental Sensing and Monitoring Technologies: Global Markets; IAS030C; BCC Research: Wellesley, MA, 2014.
About the Author: Joel Creswell is an environmental chemist and a AAAS Fellow on the EPA Office of Research and Development’s Innovation Team. Prior to coming to EPA, he worked on developing environmental trace metals analyzers for a scientific instrument company.
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