The frequency, severity and duration of heatwaves have increased across much of the world. In regions where high temperatures are already common, these heatwave events can be especially dangerous. In 2023, heat caused 365 deaths in Texas, rising to 562 when including deaths where heat was a contributing cause.
In August 2024, the south-west United States experienced another devastating heatwave. In Dallas and Houston, temperatures ranged between 100–110 °F (38–43 °C). The heat peaked in the Texan city of Abilene, where temperatures reached an all-time high of 113 °F (45 °C) – the city’s hottest day since records began in 1885.
But high temperatures might not be the only risk during a heatwave – according to new research, heatwaves may also increase the local level of airborne pollutants.
The research, presented at the fall meeting of the American Chemical Society (ACS Fall 2025), analyzed air samples that had been collected on the Texas A&M University (TAMU) campus between August 5 and September 3, 2024. During this time, local temperatures ranged between 90–106 °F (32–41 °C).
The analysis showed elevated levels of ozone, oxygenated volatile organic compounds (VOCs) and acid-rich nanoparticles when temperatures rose. The researchers also observed that during heatwaves, trees release more natural VOCs than usual – including isoprene, a precursor to ozone.
To learn more about the relationship between heat and air quality, Technology Networks spoke to Bianca Aridjis-Olivos, a PhD candidate in aerosol and atmospheric chemistry at TAMU, who presented the research at ACS Fall 2025.
Alexander Beadle (AB):
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
What prompted you and the team to investigate the link between heatwaves and air quality? And why might higher temperatures affect air pollutant levels?
PhD Candidate
Texas A&M University
Bianca Aridjis-Olivos is a PhD student in the Zhang Research Group at Texas A&M University, where she studies the intersection of atmospheric chemistry and climate. Her research focuses on the photochemical oxidation of biogenic aerosols, particularly secondary organic aerosol (SOA) formation from pinene, and their impacts on air quality and climate. She has conducted both chamber and field experiments, including a pilot campaign in College Station investigating how heatwaves influence atmospheric composition.
Her work integrates advanced mass spectrometry with mechanistic and modeling approaches to advance our understanding of multiphase aerosol chemistry and its role in climate forcing. Outside of the lab, Bianca is an educator and mentor, serving as a teaching assistant for undergraduate chemistry and as a mentor in STEM outreach programs for Bryan and College Station Independent School District.
Being a native Texan, I’ve always been aware of how extreme our summers can get, and that personal experience made me curious about how heat shapes the air we breathe. When I joined Dr. Renyi Zhang’s research group at TAMU, known for its work in atmospheric chemistry and aerosols, I became especially interested in how climate-driven heatwaves interact with air quality.
This project grew out of a TAMU interdisciplinary grant aimed at connecting climate, chemistry and public health. Higher temperatures speed up the reactions that form pollutants like ozone and secondary aerosols.
With rising summer temperatures and increasing health risks in Texas, we set out to directly measure how extreme heat events affect atmospheric chemistry and air quality in August of 2024.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
How were the air samples taken for this study analyzed? How do you isolate the effects of heat alone, without interference from wildfire smoke or other factors?
PhD Candidate
Texas A&M University
Bianca Aridjis-Olivos is a PhD student in the Zhang Research Group at Texas A&M University, where she studies the intersection of atmospheric chemistry and climate. Her research focuses on the photochemical oxidation of biogenic aerosols, particularly secondary organic aerosol (SOA) formation from pinene, and their impacts on air quality and climate. She has conducted both chamber and field experiments, including a pilot campaign in College Station investigating how heatwaves influence atmospheric composition.
Her work integrates advanced mass spectrometry with mechanistic and modeling approaches to advance our understanding of multiphase aerosol chemistry and its role in climate forcing. Outside of the lab, Bianca is an educator and mentor, serving as a teaching assistant for undergraduate chemistry and as a mentor in STEM outreach programs for Bryan and College Station Independent School District.
For this study, we deployed a suite of advanced instruments on the TAMU campus to capture both trace gases and aerosol properties alongside meteorological conditions.
For my portion of the field campaign, I worked with a high-resolution time-of-flight mass spectrometer designed for real-time analysis of VOCs at extremely low concentrations. Using its selective reagent ionization SRI capabilities, we alternated between proton transfer reaction (PTR) and NH₄⁺ modes every 30 minutes, which allowed us to detect and quantify a wide range of VOCs and oxygenated VOCs. To complement these measurements, we also operated two analyzers for ozone and nitrogen oxides, respectively. Together, these provide a comprehensive picture of the gases and particles present during the August 2024 heatwave event.
Fire smoke is easily distinguishable by chemical measurements, such as high NOx and CO. Our measurements showed low levels for those species. Also, the back trajectory analysis showed little influence from wildfires.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
What correlations did you see between airborne pollutants and low/high temperatures? What surprised you the most about these findings?
BAO:
PhD Candidate
Texas A&M University
Bianca Aridjis-Olivos is a PhD student in the Zhang Research Group at Texas A&M University, where she studies the intersection of atmospheric chemistry and climate. Her research focuses on the photochemical oxidation of biogenic aerosols, particularly secondary organic aerosol (SOA) formation from pinene, and their impacts on air quality and climate. She has conducted both chamber and field experiments, including a pilot campaign in College Station investigating how heatwaves influence atmospheric composition.
Her work integrates advanced mass spectrometry with mechanistic and modeling approaches to advance our understanding of multiphase aerosol chemistry and its role in climate forcing. Outside of the lab, Bianca is an educator and mentor, serving as a teaching assistant for undergraduate chemistry and as a mentor in STEM outreach programs for Bryan and College Station Independent School District.
Under persistent extreme heat, ozone concentrations rose and at times approached the National Ambient Air Quality Standard limit of 70 ppb. The combination of high biogenic emissions and strong solar radiation created an environment for enhanced photochemical production of secondary pollutants like ozone.
What surprised me most was how quickly pollutants accumulated during extreme heat. It showed that heatwaves trigger cascading health risks. Not just from high temperatures, but also from the chemical processes that worsen air quality and impact respiratory health.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
Your findings suggest that trees may release more natural VOCs during heatwave conditions. Why might this be, and are they a potential concern?
PhD Candidate
Texas A&M University
Bianca Aridjis-Olivos is a PhD student in the Zhang Research Group at Texas A&M University, where she studies the intersection of atmospheric chemistry and climate. Her research focuses on the photochemical oxidation of biogenic aerosols, particularly secondary organic aerosol (SOA) formation from pinene, and their impacts on air quality and climate. She has conducted both chamber and field experiments, including a pilot campaign in College Station investigating how heatwaves influence atmospheric composition.
Her work integrates advanced mass spectrometry with mechanistic and modeling approaches to advance our understanding of multiphase aerosol chemistry and its role in climate forcing. Outside of the lab, Bianca is an educator and mentor, serving as a teaching assistant for undergraduate chemistry and as a mentor in STEM outreach programs for Bryan and College Station Independent School District.
During our study we observed that trees released more biogenic volatile organic compounds, or BVOCs, under extreme heat. Plants emit these VOCs as part of their natural stress response and emissions tend to rise when temperatures are high and sunlight is intense.
On their own, these compounds aren’t necessarily harmful. But once they’re released into the atmosphere, they react rapidly with sunlight and other pollutants to form ground-level ozone and secondary organic aerosols. And that’s where the concern comes in: higher biogenic VOC emissions during heatwaves can fuel chemical reactions that worsen air quality, compounding the health risks people already face during extreme heat events.
Science Writer & Editor
Technology Networks
Alexander Beadle is a science writer and editor for Technology Networks. He holds a masters degree in Materials Chemistry from the University of St Andrews, Scotland.
What are the next steps for this research?
PhD Candidate
Texas A&M University
Bianca Aridjis-Olivos is a PhD student in the Zhang Research Group at Texas A&M University, where she studies the intersection of atmospheric chemistry and climate. Her research focuses on the photochemical oxidation of biogenic aerosols, particularly secondary organic aerosol (SOA) formation from pinene, and their impacts on air quality and climate. She has conducted both chamber and field experiments, including a pilot campaign in College Station investigating how heatwaves influence atmospheric composition.
Her work integrates advanced mass spectrometry with mechanistic and modeling approaches to advance our understanding of multiphase aerosol chemistry and its role in climate forcing. Outside of the lab, Bianca is an educator and mentor, serving as a teaching assistant for undergraduate chemistry and as a mentor in STEM outreach programs for Bryan and College Station Independent School District.
Our findings really highlight the cascading health risks that come with heatwaves – not just from the heat itself, but also from the way they impact air quality. The next step is to dig deeper into the data and share those insights through upcoming publications, so we can better understand how extreme heat events shape both atmospheric chemistry and public health.
