News Topics

Fire Research

2016 - 2024

NOAA and CIRES researchers have led efforts to better understand the atmospheric implications of biomass burning and forest fires. Our scientists conducted air quality studies and made observations during multiple prescribed and wildfire occurrences, and field campaigns during wildfire season in the western U.S. These efforts have resulted in scientific findings related to ozone pollution and other air quality challenges, as well as stratospheric aerosol resulting in climate change. CSL researchers have published or contributed to peer-reviewed science papers on these topics:

Field Campaigns

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• Ahern, A.T., C.A. Brock, M. Lyu, K. Slovacek, R.H. Moore, and D.M. Murphy, Direct measurements and implications of the aerosol asymmetry parameter in wildfire smoke during FIREX-AQ, Journal of Geophysical Research, doi:10.1029/2024JD042091, 2025. Smoke from wildfires affects how much sunlight is absorbed by the planet and its atmosphere by scattering some of that light into space. Usually, which direction the light scatters (into space vs. towards Earth) is based on models or inferred from indirect measurements of the smoke optical properties. We measured the direction of the light scattering directly, and show that more light is scattered into space than is typically thought.
• June, N.A., E.B. Wiggins, E.L. Winstead, C.E. Robinson, K.L. Thornhill, K.J. Sanchez, R.H. Moore, D. Pagonis, H. Guo, P. Campuzano-Jost, J.L. Jimenez, T. Shingler, M.M. Coggon, J. Peischl, A. Dayalu, M. Mountain, S.H. Jathar, M.J. Alvarado, and J.R. Pierce, Look within: Intraplume differences on smoke aerosol aging driven by concentration gradients, Journal of Geophysical Research, doi:10.1029/2024JD042359, 2025. Wildfires are an important source of aerosol particles to the atmosphere. These aerosol particles are important for climate and human health. A 2019 field campaign flew an aircraft through wildfire smoke plumes in the western United States to take measurements of gasses and aerosol particles in the plume. We use these measurements and a high-resolution model to study the fine scale details of the evolution of the aerosol particles in the plume. In our case study, we find that there are differences in the evolution within the plume as a function of height due to temperature and concentration effects in the plume. These fine scale details have implications for large-scale air quality and climate models, which cannot resolve these plumes explicitly.
• Tang, W., L.K. Emmons, C. Wiedinmyer, D.B. Partha, Y. Huang, C. He, J. Zhang, K.C. Barsanti, B. Gaubert, D. Jo, J. Zhang, R. Buchholz, S. Tilmes, F. Vitt, C. Granier, H.M. Worden, and P.F. Levelt, Disproportionately large impacts of wildland-urban interface fire emissions on global air quality and human health, Science Advances, doi:10.1126/sciadv.adr2616, 2025. Fires in the wildland-urban interface (WUI) are a global issue with growing importance. However, the impact of WUI fires on air quality and health is less understood compared to that of fires in wildland. We analyze WUI fire impacts on air quality and health at the global scale using a multi-scale atmospheric chemistry model—the Multi-Scale Infrastructure for Chemistry and Aerosols model (MUSICA). WUI fires have notable impacts on key air pollutants [e.g., carbon monoxide (CO), nitrogen dioxide (NO2), fine particulate matter (PM2.5), and ozone (O3)]. The health impact of WUI fire emission is disproportionately large compared to wildland fires primarily because WUI fires are closer to human settlement. Globally, the fraction of WUI fire–caused annual premature deaths (APDs) to all fire–caused APDs is about three times of the fraction of WUI fire emissions to all fire emissions. The developed model framework can be applied to address critical needs in understanding and mitigating WUI fires and their impacts.
• Wang, X., R.K. Chakrabarty, J.P. Schwarz, S.M. Murphy, E.J.T. Levin, S.G. Howell, H. Guo, P. Campuzano-Jost, and J.L. Jimenez, Dark brown carbon from biomass burning contributes to significant global-scale positive forcing, One Earth, doi:10.1016/j.oneear.2025.101205, 2025. Light-absorbing organic aerosol, known as brown carbon (BrC), is a warming agent affecting global climate. Recent evidence reveals that wildfires and agricultural burning emit a distinct class of material, dark BrC (d-BrC), with significant visible and near-infrared absorption not yet evaluated in climate models. Here, we present a global model simulation showing that d-BrC contributes a substantial radiative effect via its solar radiation absorption, comparable to black carbon and far exceeding traditional BrC estimates. Comparisons against aircraft measurements suggest that inclusion of d-BrC resolves some discrepancies between simulated and observed aerosol absorption unexplained by uncertainties in other aerosols. Findings identify d-BrC as a critical climate forcer and highlight the importance of incorporating d-BrC into models to accurately assess climate impacts of aerosols and fires.
• Carroll, B.J., W.A. Brewer, E. Strobach, N. Lareau, S.S. Brown, M.M. Valero, A. Kochanski, C.B. Clements, R. Kahn, K.T. Junghenn Noyes, A. Makowiecki, M.W. Holloway, M. Zucker, K. Clough, J. Drucker, K. Zuraski, J. Peischl, B. McCarty, R. Marchbanks, S. Sandberg, S. Baidar, Y.L. Pichugina, R.M. Banta, A. Klofas, B. Winters, and T. Salas, Measuring coupled fire-atmosphere dynamics: The California Fire Dynamics Experiment (CalFiDE), Bulletin of the American Meteorological Society, doi:10.1175/BAMS-D-23-0012.1, 2024. Wildfires are deeply impactful events with a broad range of social, economic, and environmental consequences. Fires pose major threats to health and property, and the emitted smoke often has harmful air quality impacts both locally and across continents. This creates a need for accurate fire forecast models that couple to standard weather forecasting models, but verifying the accuracy of these models with measurements is difficult due to the safety and logistics challenges of making measurements near active wildfires. CalFiDE was designed to make such challenging measurements. Scientists measured fire behavior and the related winds and smoke emissions at five wildfires in California and Oregon in 2022. Instruments were installed on a research airplane and multiple trucks to quickly deploy to wildfires. Infrared cameras on the airplane captured the fire shape and intensity at each pass of the airplane over the fire, alongside a Doppler lidar that measured winds from a distance to capture the strong updraft over the fire as well as mixing motions of smoke with cleaner air, and the ambient wind conditions. Monitoring the evolution of these coupled fire-atmosphere processes was a major goal of CalFiDE. Chemical measurements were also used to study the smoke emitted from the fires, helping understand the changes that occur between the fire and poor air quality downwind. Another Doppler lidar on a truck observed smoke trapped near the surface in valleys, which reached dangerous concentrations under stagnant conditions before being cleared out by stronger winds. CalFiDE provided an unprecedented dataset to improve our understanding and forecasting of wildfires and their interactions with the atmosphere. Read More
• Yu, P., R.W. Portmann, Y. Peng, C.-C. Liu, Y. Zhu, E. Asher, Z. Bai, Y. Lu, J. Bian, M. Mills, A. Schmidt, K.H. Rosenlof, and O.B. Toon, Radiative forcing from the 2014-2022 volcanic and wildfire injections, Geophysical Research Letters, doi:10.1029/2023GL103791, 2023. This study finds that stratospheric aerosols from volcanoes and wildfires slow down the rate of global warming. In the past decade, aerosols from volcanoes and wildfires have offset about 26% of the increase in radiative forcing and 20% of the increase in the planet's surface temperature - but these aerosols won't be able to cool down Earth for much longer as greenhouse gas concentrations increase. Read More
• Langford, A.O., C.J. Senff, R.J.A. II, K.C. Aikin, R. Ahmadov, W.M. Angevine, S. Baidar, W.A. Brewer, S.S. Brown, E.P. James, B.J. McCarty, S.P. Sandberg, and M.L. Zucker, Were wildfires responsible for the unusually high surface ozone in Colorado during 2021?, Journal of Geophysical Research, doi:10.1029/2022JD037700, 2023. The summer of 2021 was a smoky one for Denver and northeastern Colorado. Smoky haze from wildfires in Arizona, California, and the Pacific Northwest shrouded the Front Range mountains and cast a gray pallor over the sky on a near-daily basis. The typical pattern of monsoon-driven summer thunderstorms that normally flush out stagnant air in July and August largely failed to materialize, allowing smog cooked under the summer sun in 90-degree heat to pool along the base of the foothills to the west. All that added up to a record number of days when ground-level ozone exceeded the National Ambient Air Quality Standard (NAAQS). Read More
• Solomon, S., K. Stone, P. Yu, D.M. Murphy, D. Kinnisond, A.R. Ravishankarae, and P. Wang, Chlorine activation and enhanced ozone depletion induced by wildfire aerosol, Nature, doi:10.1038/s41586-022-05683-0, 2023. This study shows the Australian wildfires widened the ozone hole by ten percent in 2020. A wildfire can pump smoke up into the stratosphere, where the particles drift for over a year. While suspended there, these particles can trigger chemical reactions that erode the protective ozone layer shielding the Earth from the sun's damaging ultraviolet radiation. Read More
• Katich, J.M., E.C. Apel, I. Bourgeois, C. Brock, T.P. Bui, P. Campuzano-Jost, R. Commane, B. Daube, M. Dollner, M. Fromm, K.D. Froyd, A.J. Hills, R.S. Hornbrook, J. Jimenez, A. Kupc, K.D. Lamb, K. McKain, F. Moore, D.M. Murphy, B.A. Nault, J. Peischl, A.E. Perring, D.A. Peterson, E.A. Ray, K.H. Rosenlof, T. Ryerson, G.P. Schill, J.C. Schroder, B. Weinzierl, C. Thompson, C.J. Williamson, S.J. Wofsy, P. Yu, and J.P. Schwarz, Pyrocumulonimbus significantly impact the stratospheric aerosol budget, Science, doi:10.1126/science.add3101, 2023. Images of vast clouds of wildfire smoke towering into the sky have become all too familiar from recent active fire years across the western United States and Australia. A team of atmospheric scientists led by NOAA has demonstrated these big vertical plumes of wildfire smoke have a major long term impact on the stratosphere - and climate. Read More
• Shuman, J.K., J.K. Balch, R.T. Barnes, P.E. Higuera, C.I. Roos, D.W. Schwilk, E.N. Stavros, T. Banerjee, M.M. Bela, J. Bendix, S. Bertolino, S. Bililign, K.D. Bladon, P. Brando, R.E. Breidenthal, B. Buma, D. Calhoun, L.M.V. Carvalho, M.E. Cattau, K.M. Cawley, S. Chandra, M.L. Chipman, J. Cobian-Iñiguez, E. Conlisk, J.D. Coop, A. Cullen, K.T. Davis, A. Dayalu, F. De Sales, M. Dolman, L.M. Ellsworth, S. Franklin, C.H. Guiterman, M. Hamilton, E.J. Hanan, W.D. Hansen, S. Hantson, B.J. Harvey, A. Holz, T. Huang, M.D. Hurteau, N.T. Ilangakoon, M. Jennings, C. Jones, A. Klimaszewski-Patterson, L.N. Kobziar, J. Kominoski, B. Kosovic, M.A. Krawchuk, P. Laris, J. Leonard, S.M. Loria-Salazar, M. Lucash, H. Mahmoud, E. Margolis, T. Maxwell, J.L. McCarty, D.B. McWethy, R.S. Meyer, J.R. Miesel, W.K. Moser, R.C. Nagy, D. Niyogi, H.M. Palmer, A. Pellegrini, B. Poulter, K. Robertson, A.V. Rocha, M. Sadegh, F. Santos, F. Scordo, J.O. Sexton, A.S. Sharma, A.M.S. Smith, A.J. Soja, C. Still, T. Swetnam, A.D. Syphard, M.W. Tingley, A. Tohidi, A.T. Trugman, M. Turetsky, J.M. Varner, Y. Wang, T. Whitman, S. Yelenik, and X. Zhang, Reimagine fire science for the anthropocene, Proceedings of the National Academy of Sciences (PNAS) Nexus, doi:10.1093/pnasnexus/pgac115, 2022. As wildfires cause increasing devastation worldwide, dozens of fire experts across the nation are joining together in calling for a more strategic and interdisciplinary approach to pursuing wildfire research and protecting vulnerable communities. Read More
• Bourgeois, I., J. Peischl, J.A. Neuman, S.S. Brown, C.R. Thompson, K.C. Aikin, H.M. Allen, H. Angot, E.C. Apel, C.B. Baublitz, J.F. Brewer, P. Campuzano-Jost, R. Commane, J.D. Crounse, B.C. Daube, J.P. DiGangi, G.S. Diskin, L.K. Emmons, A.M. Fiore, G.I. Gkatzelis, A. Hills, R.S. Hornbrook, L.G. Huey, J.L. Jimenez, M. Kim, F. Lacey, K. McKain, L.T. Murray, B.A. Nault, D.D. Parrish, E. Ray, C. Sweeney, D. Tanner, S.C. Wofsy, and T.B. Ryerson, Large contribution of biomass burning emissions to ozone throughout the global remote troposphere, Proceedings of the National Academy of Sciences, doi:10.1073/pnas.2109628118, 2021. This research demonstrates that the effects of fire emissions on the atmosphere are even larger and far more widespread than previously believed, and substantially contribute to one of the most common and harmful constituents of urban pollution: ozone. Read More
• Xu, L., J.D. Crounse, K.T. Vasquez, H. Allen, P.O. Wennberg, I. Bourgeois, S.S. Brown, P. Campuzano-Jost, M.M. Coggon, J.H. Crawford, J.P. DiGangi, G.S. Diskin, A. Fried, E.M. Gargulinski, J.B. Gilman, G.I. Gkatzelis, H. Guo, J.W. Hair, S.R. Hall, H.A. Halliday, T.F. Hanisco, R.A. Hannun, C.D. Holmes, L.G. Huey, J.L. Jimenez, A. Lamplugh, Y.R. Lee, J. Liao, J. Lindaas, S.A. McKeen, J.A. Neuman, J.B. Nowak, J. Peischl, D.A. Peterson, F. Piel, D. Richter, P.S. Rickly, M.A. Robinson, A.W. Rollins, T.B. Ryerson, R.H. Schwantes, J.P. Schwarz, K. Sekimoto, V. Selimovic, T. Shingler, A.J. Soja, J.M.S. Clair, D.J. Tanner, K. Ullmann, P.R. Veres, J. Walega, C. Warneke, R.A. Washenfelder, P. Weibring, A. Wisthaler, G.M. Wolfe, C.C. Womack, and R.J. Yokelson, Ozone chemistry in western U.S. wildfire plumes, Science Advances, doi:10.1126/sciadv.abl3648, 2021. Using data gathered from a specially equipped jet that spent a month flying through and studying wildfire plumes, scientists have a better understanding now of how wildfire smoke impacts air quality. Crucially, they found a mechanism for predicting the production of the pollutant ozone. Read More

More FIREX-AQ Publications

• Gao, R.-S., K.H. Rosenlof, B. Kärcher, S. Tilmes, O.B. Toon, C. Maloney, and P. Yu, Toward practical stratospheric aerosol albedo modification: Solar-powered lofting, Science Advances, doi:10.1126/sciadv.abe3416, 2021. The dynamics that lift smoke from large wildfires into the upper atmosphere could potentially be employed one day to help temporarily cool the planet, based on the findings of this modeling study. Read More
• Yu, P., S.M. Davis, O.B. Toon, R.W. Portmann, C.G. Bardeen, J.E. Barnes, H. Telg, C. Maloney, X. Wang, and K.H. Rosenlof, Persistent stratospheric warming due to 2019-20 Australian wildfire smoke, Geophysical Research Letters, doi:10.1029/2021GL092609, 2021. Research on the massive Australian bushfires in 2019 and 2020 shows that almost 1 million metric tons of smoke rose into the stratosphere, causing it to warm by about 1 degree Celsius for six months, and likely contributed to the large and persistent ozone hole that formed over Antarctica during the Southern Hemisphere's spring. Read More
• Schill, G.P., K.D. Froyd, H. Bian, A. Kupc, C. Williamson, C.A. Brock, E. Ray, R.S. Hornbrook, A.J. Hills, E.C. Apel, M. Chin, P.R. Colarco, and D.M. Murphy, Widespread biomass burning smoke throughout the remote troposphere, Nature Geosciences, doi:10.1038/s41561-020-0586-1, 2020. Smoke emitted from wildfires and agricultural burning constitutes one of the largest sources of aerosol particles to Earth's atmosphere. However, little is known about the importance of smoke on the climate system after it dissipates into remote areas of the planet. This study takes a new look at this faint, old smoke and finds that it is just as important an influence on the climate as the thick plumes produced by active fires. Read More
• Yu, P., O.B. Toon, C.G. Bardeen, Y. Zhu, K.H. Rosenlof, R.W. Portmann, T.D. Thornberry, R.-S. Gao, S.M. Davis, E. Wolf, J. de Gouw, D.A. Peterson, M.D. Fromm, and A. Robock, Black carbon lofts wildfire smoke high into the stratosphere to form a persistent plume, Science, doi:10.1126/science.aax1748, 2019. Thunderstorms generated by a group of giant wildfires in 2017 injected a small volcano's worth of aerosol into the stratosphere, creating a smoke plume that lasted for almost nine months. Researchers studying the plume found that black carbon or soot in the smoke was key to the plume's rapid rise: the soot absorbed solar radiation, heating the surrounding air and allowing the plume to quickly rise. Read More
• Sekimoto, K., Koss, A. R., Gilman, J. B., Selimovic, V., Coggon, M. M., Zarzana, K. J., Yuan, B., Lerner, B. M., Brown, S. S., Warneke, C., Yokelson, R. J., Roberts, J. M., and de Gouw, J., High- and low-temperature pyrolysis profiles describe volatile organic compound emissions from western US wildfire fuels, Atmospheric Chemistry and Physics, doi:10.5194/acp-18-9263-2018, 2018. Wildfire emissions, which can be transported over long distances, can be toxic and contribute to the formation of secondary pollutants such as ozone and fine particles in the atmosphere. Those emissions affect human health and the environment, so scientists want to know what's in wildfire smoke. According to this research, what matters most is not what kind of fuel is burning, but the temperature at which it burns. Read More

More FIREX Firelab Publications