Daniel Mendoza brings science (and change) to the people.

Daniel Mendoza

A research associate professor in the Department of Atmospheric Sciences at the University of Utah, Daniel Mendoza is not your typical academic scientist. With an impressive list of publications, averaging a new paper each month, academic scholarship is only one of his accomplishments. Mendoza has become an environmental social justice advocate, leveraging his research to get the attention of politicians and legislatures. The intersection between what’s happening in the atmosphere and what’s happening on the ground in people’s lives is where Mendoza readily enters.

This summer, Salt Lake has fallen victim to heat waves that mirror those throughout the United States. According to the CDC, extreme heat kills around a thousand people in the U.S. each year, more than any other natural-occurring factor. Effects from the heat are easily felt, but more insidious are the effects from increased concentrations of air pollutants, namely ozone. 

Mendoza explains in an interview with @theU’s Lisa Potter that “ozone is dangerous because it basically causes a sunburn in your lungs that impacts respiratory and cardiovascular health.”

In a recent study, Mendoza and his team asked the question, “can cool zones protect individuals from heat and poor air quality?” “Cool zones” are public buildings that serve as environmental refuges for vulnerable people during periods of extreme heat. Places like recreation centers or libraries are good examples of cool zones; Mendoza chose the Millcreek Library as the location for his case study. 

Obviously cool zones protect individuals from heat with the use of air conditioning, but the study found that the Millcreek Library also reduced exposure to atmospheric ozone by around 80%. 

Given their demonstrated efficacy, Mendoza is now critical of the current scope of cool zones. “We should be thinking about how to make these centers more accessible, for example, keeping them open for longer hours to protect people during the hottest parts of the day.” Many heat refuges close around 2-3 p.m. and aren’t open on weekends.

What people believe

Daniel Mendoza in the 2021 documentary "AWAiRE" that explores the impacts of air quality along the Wasatch Front. Credit: AWAIRE.

Mendoza understands that data alone is not convincing enough to enact change outside of the scientific community. “About 50% of people in the U.S. believe in climate change, but 100% believe in lung cancer, which is why I wanted to pivot from more climate drivers and greenhouse gas emissions and products towards more health criteria,” he says. Furthermore, he continues, “...150% of people believe in the dollar. I mean that’s ultimately what drives policy, what drives a lot of decision making.” 

It was during his Pulmonary and Critical Care Medicine Fellowship program at the U when Mendoza learned more about how to tie in the social and basic sciences with the health sciences. He finished the program in 2020 after completing a capstone project looking at the impact of air pollution on school absences. 

On “orange” or “red” air quality index (AQI) days, students are often still sent outside for recess, resulting in many children experiencing respiratory symptoms and needing to be sent home. Missing school every so often because the air quality is poor doesn’t sound like a huge issue, but it adds up to impact the student as well as the school, its district and the city where they live, he explains.

“When you have repeat absenteeism, then the potential to graduate is much lower, the potential to go to college is much lower, then your tax base is lower,” says Mendoza. Increased school absences cost the city around half a million dollars a year in terms of reduced workforce, education costs and healthcare costs. 

The solution to this pervasive issue of children being sent home because of the deleterious effects of bad air was surprisingly simple: emergency asthma inhalers in every classroom, right next to the Epinephrine Auto-Injectors branded “EpiPens” Says Mendoza, “I worked with Representative Mark Wheatley,” chair for the Utah Asthma Task Force, “and we passed a law…. Utah became the 14 (or 15th) state that has emergency asthma inhalers in every single school.” 

Now on bad air days, instead of sending a student home, students can use the rescue inhaler and remain at school, placing less of an economic burden on the city and giving themselves more time to learn. It’s a health-issue solution based on atmospheric data that changes policy and in turn saves taxpayer dollars. 

Empowering the Community 

Mendoza soon discovered what others had already discovered or at least suspected, that certain populations in the city were more endangered than others. What distinguished those populations was lower-income brackets and racial and ethnic inequities. When he first moved to Salt Lake City, Mendoza was excited about the buzz around air quality. “I thought, this is great. My research is going to be welcomed by the community,” he recalls. Instead, he discovered that these events were forgetting a key part of the problem: the people who are most impacted. 

Mendoza started attending community-based informational gatherings about climate change and the environment. “All of these events are held east of State Street. They were all in English. No one looked like me. Then at the end of the talk, the conclusion was ‘buy electric vehicles and solar panels and we’ll save the world together.’ Well that doesn’t work for everyone.” 

Not only is there a disparity in the communities affected by poor air quality, there is an inequality in accessible solutions to the problem. “For most of them, air quality is not a top priority… they don’t have the luxury of learning like we do,” says Mendoza of those who are most likely to be impacted by bad air quality. 

The first step in empowering the community and addressing this imbalance was to bring science to them. Mendoza began organizing outreach events, this time on the west side of State Street, held in both Spanish and English. 

“We provide them with actionable solutions. For example, we partnered with Utah Clean Energy, and we did an LED exchange where people bought in their normal light bulbs,” he says. Another switch he facilitated was to low-flow showerheads. 

And yet another initiative included furnace filter exchange with 100 homes in Salt Lake County. When indoor air was tested for 43 different potential problematic elements, researchers found elevated levels of uranium, lanthanides, arsenic and lead, “all the nasties.” 

Those “nasties” come from a variety of sources. “If you’re close to a highway, for example, you [breathe in] more of aluminum, associated with brake wear,” says Mendoza of the indoor air quality study, the first study of its kind. “When was the last time you sat outside for eight hours? You spend 90% of your time indoors and 60% of your time in your home, roughly speaking.” 

“The people that we really are very concerned about are, for example, the delivery drivers, who are constantly in that traffic, road construction workers as well. Those people are breathing [in] literally every single car’s tailpipe.” 

‘Run back inside’

Inequities in who breathes bad air requires that one looks closely at why and how bad air gets ingested. “Those with more and better resources can think about these issues involving bad air and what used to be only seasonal atmospheric inversions along the Wasatch Front, and then “just run back inside and we’re fine. But very few studies have been done on these concentrated pollution sources, again in conjunction with what they may be exposed to ‘naturally.’” 

From the 2021 documentary "AWAiRE." Credit: AWAIRE.

Those studies are being done by Mendoza and others and then made actionable on-the- ground initiatives involving switching out devices that are less effective and cost more money in populations who are most threatened by breathing bad air. 

These simple switches in affordable fixtures, for example, have tangible and meaningful impacts that inspire other actions, other policy decisions leading to better health outcomes. 

“Participants in these gatherings  soon became community leaders to help others improve their situation,” says Mendoza, another favorable result to his work. And then there is the financial incentive, that tongue-in-cheek statistic that 150% of people do in fact “believe in the dollar.” 

“These community members, they have to earn income to survive,” he reminds us. “They see their electric bills go down, they see their heating bills go down, they see their water bills go down, and they realize ‘Oh,okay, so it works. Let me tell all my friends about it.’”

“We’re starting to see a globally consistent system to track [carbon] emission changes take shape,” says atmospheric scientist John Lin.

Faculty in the University of Utah's Department of Atmospheric Sciences, Lin is co-author of a paper in the journal Environmental Research Letters about a new satellite-based system for measuring CO₂ emissions in support of global collective climate mitigation actions. As nations and cities continue to state their intentions to decarbonize for the purpose of becoming, in their activities, carbon-neutral, “we want to be able to see it happen from space.” 

Now we have a system to do so. 

That system is the culmination from standing on the shoulders of previous data scientists. It’s a story about how data is collected, interpreted and expanded through new technologies. It’s also about how this recursive process — now turbocharged with the advent of machine learning and AI — creates a space for potential application, innovation and policy that can change our world for the better, including mitigating carbon emissions that are warming our earth at a startling and deleterious rate.

But before any attempt can be made to save the planet, scientists have to secure a consistent measurement framework to better understand what’s happening as well as where it’s happening and how much.

The Backstory

John Lin

The backstory to this tale first begins in the Pacific Ocean. Tracking carbon emissions dates back decades to a single site in Hawai’i where, on a largely inactive volcano on the Big Island, instruments measured carbon dioxide in the atmosphere. At a high elevation, the site was very good at characterizing broad scale changes in carbon dioxide, globally, a “poster child for climate change because over time,” explains Lin who is also associate director of the Wilkes Center for Climate Science and Policy, “we know that from these Hawai’i  measurements, CO₂ has this distinct cycle, seasonally, but then this upward trend due to all of us burning fossil fuels.”

Human-caused carbon emissions are not only leading to CO₂ buildup everywhere in the atmosphere but the issue is widespread in public discourse. Whether it’s on the micro level of mitigating one’s personal “carbon footprint” by taking the bus, or on the meta level of international initiatives like the Kyoto Accords or the United Nations-brokered Paris Agreement, the effects of carbon emissions are on everyone’s mind. A cascade of cities and whole nations have established goals for mitigating emissions, but their estimates of carbon emissions have been relying on data that are inconsistent and sometimes missing altogether in parts of the world. 

That cities have singly established and even accelerated their carbon-neutral goals is a good thing, considering that over 70 percent of human-emitted CO₂ into the atmosphere stems from cities around the globe.

Tracking progress toward city-scale emissions reduction targets is essential by providing “actionable information for policy makers,” the paper states. This while the authors acknowledge that earlier measurements and claims from municipal entities are based on “self-reported emissions inventories,” whose methodology and input data often differ from one another. These practices hamper “understanding of changes in both city-scale emissions and the global summation of urban emissions mitigation actions.”

Orbiting Carbon Observatory

This is where outer space in general comes into play and, in particular, the Orbiting Carbon Observatory (OCO). The NASA mission is designed to make space-based observations of carbon dioxide in Earth’s atmosphere to better understand the characteristics of climate change. After a literal “failure to launch” in 2009, NASA successfully placed a satellite (OCO2) in 2014 with equipment measuring CO₂ emissions from space. Satellite-transmitted data promised to be an independent way to calculate, globally, emissions from cities. Not surprisingly, it has taken a while to learn how to use the data. In 2020 a graduate student in Lin’s research group, Dien Wu, developing early methods, did exactly that, looking comprehensively at a total of twenty cities around the world.

Based on essentially the same data set used by Lin and Wilmot in their current paper, but with fewer years, Wu was able to get estimates of the amounts of human emitted CO₂ from OCO2 satellite transmissions. Separating out what carbon human activity is emitting to the atmosphere versus those from urban vegetation has now been determined through an expansion of the analyses over the additional years by Lin’s team of researchers, including a later graduate student by the name of Kai Wilmot, co-author of the current study.

In this round, four times as many urban areas as Wu studied and distributed over six continents, have now been assessed. This plant/human conundrum is further complicated by vegetation outside the city which has very different characteristics from vegetation inside the city. The difference creates patterns of CO₂  that have to be taken out to distill the human component.

Strangely beautiful animations

Kai Wilmot

In short, Lin and company’s findings, published in Environmental Research Letters, represents a new capacity based on recent developments in modeling. And the animations of the assembled and interpreted satellite CO₂ data delivered by the team are startling, even strangely beautiful. In one chart the left side displays latitude vs CO₂. “This narrow swath,” explains Lin, indicates “each time … [the satellite] orbits. There's this narrow slice of data that becomes available.”

Using that data, he continues, “the NASA scientists can construct this nice animation of CO₂ change in each latitude band over time.” Lin points to what he calls “ridges and valleys” on the the chart that represent the seasonal cycle, and he personifies the entire Earth as if it is “breathing in the carbon dioxide through photosynthesis during the summer growing season and then releasing it in the winter. They have these very sharp ridges — high CO₂, low CO₂, higher CO₂ [the breaths] — but overall, the rug is going up, because we're emitting carbon dioxide into the atmosphere.”

Here, researchers are only looking at a small fraction of data points, the ones that intersect the targeted cities. They then do a more detailed look at whether they’re seeing a signal or not and whether they’re getting enough data.

“Personally,” says Wilmot, “I think the particularly neat aspect of this work is the capacity for global application. Leveraging satellite data and atmospheric modeling, we are able to gain some insight into urban emissions at cities around the world. We can see interactions between these emissions and socioeconomic factors, and we can identify large changes in emissions over time.”

The possibilities of creating more rigorous models, and more revealing data about how much cities emit carbon to the atmosphere are tantalizing. And so are the findings of the research. “This kind of information can be used by cities and the UN process,” Lin says. “But I’m pretty sure what they want is something more dynamic through time, how these emissions evolve. And also, probably more frequent updates.” As it was in this study, researchers had to aggregate multiple years of data to get enough points for each city. “So the challenge, I think, is to be able to track more dynamically these emissions over time.”