Three Oxygens
There is good ozone and bad ozone. We are discussing the bad ozone today, the one we breathe and can be harmful to our health. Daniel Mendoza, a research associate professor at the University of Utah, discusses the chemistry behind ozone formation, primarily from nitrogen oxides and volatile organic compounds intensified by sunlight. Daniel has started a project to measure air quality and heat in rural Utah communities, using both indoor and outdoor sensors. The discussion includes the challenges of ozone measurement, the role of vegetation like sagebrush in VOC emissions, and the potential benefits of using public cooling centers as environmental refuges. The episode underscores the need for more awareness and education about ozone’s health impacts, especially for tourists in areas like Moab.
Meet the Scientist: Daniel Mendoza
Dr. Daniel Mendoza holds joint appointments as Research Associate Professor in the Department of Atmospheric Sciences and Adjunct Associate Professor in the Pulmonary Division in the School of Medicine, and the Department of City & Metropolitan Planning at the University of Utah. His research interests include quantifying and characterizing urban greenhouse gas, criteria pollutant emissions, and temperature for use in human exposure estimation and metropolitan planning. He also examines the health effects associated with acute and chronic pollutant exposure, particularly in vulnerable populations. He is the Director for the Dark Sky Studies Minor and instructor of the Capstone Class on Dark Sky Studies at the University of Utah.
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Interview Excerpt - Unveiling Ozone
OZONE is an invisible gas that is generally created by mixing nitrogen oxides, most commonly by burning fossil fuels, and can be intensified by heat. Science Moab speaks with Daniel Mendoza, a research associate professor in the Department of Atmospheric Sciences at the University of Utah, who recently started a program in rural Utah communities, including Moab, to monitor air quality and ozone levels.
Science Moab: Can you begin by describing the science behind ozone?
Mendoza: Ozone is not something that is created by us directly. Ozone generally is created by mixing nitrogen oxides, which are generally byproducts of combustion, mainly from vehicles and VOCs, which are volatile organic compounds. The reason why they’re called Volatile Organic is because you can smell them. So when those two are present, and then you have sunlight, then the chemistry ends up forming ozone, which is three oxygen molecules together.
Let’s go a little deeper here. We all live in what’s called a troposphere. That’s the lowest layer of the atmosphere. Right above us is the stratosphere. Ozone in the stratosphere…let’s call it the good ozone. That’s where we had those concerns about the hole in the ozone layer in Antarctica, because that actually absorbs the UV ray. Without them, we would have, we would be exposed to much more UV rays.
However, the ozone where we are, in the troposphere, that’s a harmful one. That’s the one that we actually do create generally ourselves.
Science Moab: Okay, because ozone has to have that component of sunlight, is it more harmful when the sun is high in the sky…either midday or summer months where it’s more intense than others?
Mendoza: Yes. And in addition to that, part of the reason why it’s much more of a problem during the summer is because we do have a lot of the VOCs from plants and they’re more active during the warmer season. So NOx, we have plenty of…whenever there’s a car…we have lots of it. But we do have those two limiters, which are the VOCs as well as the sunlight.
So I would say that in a way, ozone follows very similar patterns as temperature patterns. So when we’re seeing the hottest parts of the day, and it’s during the warmer months, that’s when you’re likely to also have the highest ozone levels.
Science Moab: You have projects all over the state, but recently you have begun a monitoring campaign here in Moab for both heat and air quality. what’s the main purpose of doing that here in Moab?
Mendoza: This is a project sponsored by the University of Utah that we recently started called the RAC, the Remote and Aster Communities.
Generally, air quality, heat, and environmental exposure studies are centered around population centers. We wanted to see if it was possible that ozone could be higher in rural communities.
One thing that has been noted in previous studies, is that sagebrush is one of the highest sources of VOCs. Now, there is a misconception that simply because there’s no large roads or factories, that rural communities could have excellent air quality.
When you have communities that are rural and largely vegetated with specifically sagebrush and similar VOC sources, then all of a sudden a road is built there and there’s traffic, now you have just enough traffic (NOx), and then all of a sudden, ozone becomes so much higher.
So that’s something that we really are trying to understand a little bit better through some better modeling and measurements.
Science Moab: What specifically are you using to collect data? you measure ozone levels and what else?
Mendoza: Yes we’re combining both outdoor and indoor data because this is part of the long term project.
Generally cooling centers are public buildings, whether they be libraries, senior centers, or rec centers. So that’s why we’ve cited the sensors at the library. We have sensors on the roof. One measures ozone and the other one measures a range of four particulate matters. So we set up a sensor inside and one outside, and we’re really seeing the differences there and how protective an environment such as the library is and its potential as a cooling center.
When pollution levels are at a certain level, we encourage schools to consider keeping students inside during recess. So that’s really primarily a function of the outdoor sensors, but we’re also interested in how protective an indoor environment can be, such as, in this case, the library.
Science Moab: With a lot of this data, you’re trying to educate people and then also offer some alternatives, like the cooling centers as refuges.
Mendoza: We are very interested in working with Moab, because it’s obviously a tourist destination, and there may be people who are not only not used to the environment (how hot, how dry it is) but also may be vulnerable because they’re jet lagged. And if you’ve come from halfway across the world, you are probably exposed to completely new viruses or bacteria on the plane, so upon your arrival, your immune system is already vulnerable and then you’re exposed to environmental conditions that are substantially harsher than you may be used to.
We also have to consider that while not necessarily very high in elevation, there’s still an elevation component. And then they decide that they want to hike Delicate Arch at noon. So now there are many factors that we need to consider.
Science Moab: Yeah, so the education and the awareness could go a long way and possibly prevent some of the casualties we always have here.
