From the U.S. Government Accountability Office, www.gao.gov Transcript for: Air Quality and the Technology Used to Monitor It Description: This year's wildfires on the West Coast--as well as those during previous years--have raised concerns about air quality, especially as these disasters grow in scale and number. Despite this, national data show that the U.S. has made significant progress in reducing air pollution levels since the 1970s. But how do we know that air quality is actually getting better? We talk with two GAO experts with new work out about measuring and monitoring air quality. Joining us are--Alfredo Gomez--an expert on air quality and environmental protection issues, and a director in our Natural Resources and Environment team and Karen Howard--an expert on technology assessment and science, and a director in our Science, Technology Assessment, and Analytics Team. Related GAO Work: GAO-21-38, Air Pollution: Opportunities to Better Sustain and Modernize the National Air Quality Monitoring System & GAO-21-189SP, Science & Tech Spotlight: Air Quality Sensors Released: December 2020 [Intro Music] [Karen Howard:] Improvements in sensor technology are enhancing and improving our ability to understand and manage air quality issues, and to improve public health. [Holly Hobbs:] Hi and welcome to GAO's Watchdog Report, your source for news and information from the U.S. Government Accountability Office--I'm Holly Hobbs. This year's wildfires on the West Coast--as well as those during previous years--have raised concerns about air quality, especially as these disasters grow in scale and number. Despite this, national data show that the U.S. has made significant progress in reducing air pollution levels since the 1970s. But how do we know that air quality is actually getting better? Today we talk with two GAO experts with new work out about measuring and monitoring air quality. Joining us are: Alfredo Gomez--an expert on air quality and environmental protection issues, and a director in our Natural Resources and Environment Team. He has a new report about how air quality has changed over the last 50 years, and what concerns there are moving forward. And Karen Howard--an expert on technology assessment and science, and a director in our Science, Technology Assessment, and Analytics Team. She has a new spotlight out on how air quality is monitored, and how this technology is changing. Thank you for joining me Karen and Alfredo. [Karen Howard:] Pleasure to be here, Holly. [Alfredo Gomez:] Thank you for inviting me. [Holly Hobbs:] So Alfredo, your new report looks at air pollution and it says that air quality has improved in the U.S., but for a lot of people especially those living out west that's going to seem untrue. How can that be explained? [Alfredo Gomez:] Yes, our report notes that air quality has improved since the 1970s for certain common are pollutants--such as ozone and sulfur dioxide. We also learned during the course of our work that smoke from increasingly intense wildfires out west has threatened to offset those gains. Believe it or not, smoke from these wildfires is generally not counted in the air quality monitoring data that's used to determine compliance with the Clean Air Act. So a community that may have experienced hazardous air quality for several weeks during the wildfires can still meet national standards for air quality. [Holly Hobbs:] And what does it mean that events like wildfires which impact air quality are not counted in the data? [Alfredo Gomez:] The reason is that compliance with the Clean Air Act is based on averages of air quality across a certain time period. So for example, in calculating the average pollution levels, local agencies can ask that certain data points be excluded because they're due to exceptional events. And in this case, exceptional events being wildfires. And this is allowed in recognition that state and local governments may be powerless to control the air pollution from wildfires. [Holly Hobbs:] There's this national system for monitoring air quality. How is that system managed and operated? [Alfredo Gomez:] Our air quality system includes thousands of monitoring sites across the country that measure specific air pollutants. These sites use a variety of methods to monitor the air such as canisters or filters to collect air samples. The Environmental Protection Agency is responsible for ensuring that the system produces information that's needed to manage air quality. EPA sets the requirements for the systems design including the minimum number of monitors that different areas need to have. Now, state and local governments are the ones that are actually operating the majority of the monitoring sites, they are the ones that purchase and maintain the monitoring equipment, they also ensure that data are accurate, and they collect and report the air quality data to EPA and to the public. [Holly Hobbs:] And Karen, your new work talks about the sensor technology behind monitoring air quality. How does that technology work? [Karen Howard:] There are many different kinds of sensors, which we divide into two main categories. The first category are localized sensors and they're designed to measure air quality in the immediate vicinity of the sensor. So, for example, there are some sensors that are designed to measure airborne particles such as from wildfire smoke. And they might use lasers to estimate how many particles of a certain size are in the air sample that they collect. Or other localized sensors might detect gases such as ozone. In this case that kind of a sensor may use a meter to estimate the amount of that substance passing through the sensor. And then the second main category of sensors are satellite based sensors or basically--just what they sound like--a sensor that's attached to a satellite, so that it can make measurements from a great distance. These work very differently. They generally measure the energy reflected from the earth through the atmosphere and that allows the sensor to identify what pollutants are in the air between the satellite and the ground. And those are most useful for larger scale measurements across a wide geographic area. And then beyond the measurement itself that the sensor is making, the sensor also will likely use an algorithm to convert the raw measurement into some kind of an air quality indicator by taking into account things like the air temperature, the humidity and other factors that can affect the sensor readings. [Holly Hobbs:] Alfredo, are there challenges in operating a system like the one you and Karen described across the 50 states and the territories? [Alfredo Gomez:] The air quality monitoring infrastructure is getting old, and state and local governments face challenges in replacing aging monitoring equipment. This is because funding for monitoring programs has been declining for the last 15 years. We heard stories from state and local officials about monitoring equipment that was so old that the officials had to purchase replacement parts on eBay because it was no longer available from the manufacturer. This aging infrastructure can affect the quality of pollution data from the monitor. There are also concerns that the monitoring systems cannot meet the information needs using monitors because they require a lot of investment and simply can't be installed everywhere. [Holly Hobbs:] Karen, are there any opportunities to address some of these challenges with the new air quality sensor technology? [Karen Howard:] Definitely yes. Some technologies like the new lower cost sensors and better satellite based sensors are generating a lot of interest as potential ways to fill in some of the gaps in the current air monitoring system. Some of the low cost sensors are small enough to be attached to bikes or to clothing and carried around to understand personal exposure to pollutants. They're also cost effective enough to be installed in many locations where we couldn't previously monitor, such as rural areas. And the opportunity to improve satellite based sensors is also exciting because these sensors cover such wide swaths of the country and that can help us better understand large scale air quality issues like wildfire smoke. [Holly Hobbs:] And how accurate are these sensors? [Karen Howard:] Sensors that are deployed by federal agencies like EPA and are intended to guide regulatory decisions naturally need to be very accurate and reliable. However it also increases the cost to purchase and to maintain those sensors. Low-cost sensors operate with fewer requirements, but that means they can vary in the quality of data they produce. It can also be tricky to interpret the data from low-cost and satellite-based sensors without specialized expertise. And in some cases researchers might want to monitor for new or emerging pollutants, things like airborne chemicals that are being studied to see whether they might be linked to cancer or other longer term health effects. But if there aren't established health standards or atmospheric limits for those newer emerging substances, it can be hard to figure out whether the levels being measure in the air are a problem. [Holly Hobbs:] Alfredo, did any of these issues come up at all during your review? [Alfredo Gomez:] Yes, these issues did come up in our review as well. We found that EPA and state and local government agencies are even starting to use them for limited purposes. To learn more about these sensors, we actually installed them on our building, and like many other users we found that the devil is in the details. In some cases our sensors' data track broader air quality trends pretty well. But in other cases, different sensors in the same location did not agree with each other. So, there's still more work to be done before they can be used effectively, but they do open up a lot of new possibilities for us. [Music:] [Holly Hobbs:] So it sounds like there is still a lot of concern about air quality in the U.S.--including the public health effects of air toxics. And that there is this national system for monitoring air quality, which faces various challenges. But that there are some new sensors that open up new possibilities for improving how we monitor air quality. Karen, what are the opportunities to improve the use of sensor technology? [Karen Howard:] In terms of opportunities to improve the technology itself, one issue is that companies making sensors often target those towards the established or more well-known pollutants because they have a known market for those sensors. But this means that sensors that are able to measure newer or emergent pollutants of interest can be hard to find. In terms of sensor use, one exciting new opportunity that is opening up through the development of these low-cost sensors is the potential to set up networks of many sensors to track the formation, the movement, and the variability of pollutants over time and distance. However, even with the newer, lower cost sensors that are becoming more available, there are still questions about whether low-income communities, for example, that might need them the most will be able to have sufficient access to them. [Holly Hobbs:] Alfredo, did we make any new recommendations to improve the air quality monitoring system? [Alfredo Gomez:] Yes, we made two recommendations to the Environmental Protection Agency. The first is for EPA to develop and implement an effective asset management framework so that limited resources are directed towards the highest priorities. The second recommendation is for EPA to develop a plan to modernize air quality monitoring. Such a plan can help the agency provide the information needed to understand and address changing air quality issues--such, as wildfire smoke that we've been talking about--and air toxics, and to make better use of new technologies. [Holly Hobbs:] And last question for you Alfredo, what's the bottom line of your report? [Alfredo Gomez:] The bottom line of the report is that the monitoring system that we have is a valuable national asset for protecting the health of the public from air pollution. By taking steps to better sustain and modernize the system, EPA can ensure that it retains this value for the American people and help ensure that we all have clean air to breathe. [Holly Hobbs:] And Karen, last question for you, what's the bottom line on your report? [Karen Howard:] The bottom line is that improvements in sensor technology are enhancing and improving our ability to understand and manage air quality issues and to improve public health. However, sensor data may vary in quality and might be difficult to interpret, and sensors may not be available to measure some newer substances of concern, and may not be widely available to disadvantaged communities. [Holly Hobbs:] That was Alfredo Gomez and Karen Howard talking about GAO's recent review and spotlight on air quality and the systems used to monitor it. Thank you for your time Karen and Alfredo. [Karen Howard:] Thank you. [Alfredo Gomez:] Thank you for having me. [Holly Hobbs:] And thank you for listening to the Watchdog Report. To hear more podcasts, subscribe to us on Apple Podcasts. And make sure you leave a rating and review to let others know about the work we're doing. For more from the congressional watchdog, the U.S. Government Accountability Office, visit us at GAO.gov.