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
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