More simultaneous large fires in the next 60 years

Wildfire simultaneity, or numerous large wildfires burning at the same time, will become at least twice as frequent by 2085, researchers are warning. A steadily increasing number of large wildland fires — and the number of acres burned — has occurred over the past few decades in the American West, but new research has found that simultaneous large fires will burn even more often. 

Future regional increases in simultaneous large Western USA wildfires” was published in the International Journal of Wildland Fire by the University Corporation for Atmospheric Research; it focused on wildfires that burned 1,000 acres or more between 1984 and 2015. Researchers  used multiple fire indices to model how simultaneity will likely change over the next 60 years. The study also measured the fires by Geographic Area Coordination Centers to see whether some geographic areas might see greater increases compared with others.

changes in simultaneity

Simultaneous wildfires were projected to increase in every area of the West. Not only were “bad years” projected to increase, but increases in simultaneity also led to more intense wildfires. Peak season for simultaneous wildfires was projected to become several weeks longer by the end of the century.

“The trend was particularly pronounced for the most severe wildfire seasons — those that currently occur only every 10 years on average,” the National Center for Atmospheric Research said. “In the future, such seasons may be expected to occur at least twice as often, and up to nearly five times per decade in the northern Rocky Mountains, which was the most affected region.”

seasonality of simultaneity
Projected seasonality of simultaneity

The findings point toward a risk in an already understaffed and under-resourced wildland firefighting force. Because crews are transferred across the nation, or sometimes even across nations, to battle fires depending on when an area’s season peaks, an increase in peak season length could mean major challenges for firefighters and fire managers.

“Because firefighting decisions about resource distribution, pre-positioning, and suppression strategies consider simultaneity as a factor, these results underscore the importance of potential changes in simultaneity for fire management decision-making,” the study says.

Steps can reportedly be taken to lessen the future risk of simultaneous wildfires, including thinning forests, conducting prescribed burns, and increasing numbers of firefighting crews and equipment. But that will depend on how long it will take to make those changes.

“The strain on resources created by simultaneous fires can affect the ability to conduct prescribed burns and pursue other preventative action,” the center said.

 

Saving carbon hotspots from burning could prevent wildfires

Keeping wildland fires from spreading to human communities is the first and foremost priority of the U.S. Forest Service’s firefighters, according to the agency’s 2022 Wildfire Crisis Strategy Implementation Plan.

“Community exposure is a central factor in the strategy to confront the wildfire crisis,” the plan’s text reads. The plan goes on to identify what it called “high-risk firesheds” within National Forest Systems lands that it would focus on shifting land management towards increasing fuels and forest health treatments.

Recent research published in the Environmental Research Letters journal, however, found that the USFS hallmark decade-long plan misses the mark and doesn’t truly address what would stop more intense wildfires from igniting in the centuries to come: reducing carbon lost by wildland fire.

Conifer forests throughout the western U.S. play an integral role in sequestering and storing carbon in Earth’s atmosphere when these forests have a wildfire burning through them, carbon is not lost equally. Higher amounts of litter, duff and downed woody material consumed by fire, as well as post-fire decomposing trees, cause a greater risk of carbon loss. An increase in carbon output into Earth’s atmosphere will further increase the effects of climate change and, in turn, make wildfires more widespread and intense.

The study, a collaboration with the Forest Service, the Nature Conservancy, and University of Montana researchers, first evaluated where carbon was the most exposed and sensitive to wildfires. “Exposed” was defined as the largest concentrated areas of living and dead biomass’ burn probability, while “sensitive” compared areas for potential carbon loss and carbon recovery following wildland fire. They found that the most exposed carbon was not necessarily the most sensitive to wildfire.

“Relative to their total conifer forest area, states containing the greatest proportion of most exposed carbon … were California (63%), New Mexico (49%), and Arizona (44%),” researchers said. “In contrast, states with the greatest proportion of most sensitive carbon … were New Mexico (74%), Utah (67%), and Colorado (66%).”

Researchers then built upon the agency’s “high-risk firesheds” by combining high-risk areas for human communities and high-risk areas for wildfire-caused carbon loss.

Firesheds represented in gold to emphasize that improving reciprocal relationships between humans and forests can support multiple ecological, social, and cultural values concurrently.
Firesheds represented in gold to emphasize that improving reciprocal relationships between humans and forests can support multiple ecological, social, and cultural values concurrently.

“After overlaying our 308 opportunity hot spots on previously published maps of 140 high-risk all-lands firesheds for human communities, we observed that 64 firesheds overlapped,” the researchers said. “Here we represented those firesheds in gold to emphasize that improving reciprocal relationships between humans and forests can support multiple ecological, social, and cultural values concurrently.”

Read the full study [HERE].

University of Oregon launches new smoke research center

The University of Oregon in Eugene is launching a new research program to study effects of wildfire smoke and examine options for reducing risks. UO research professor Cass Moseley told KGW News that the center’s launch is due in part to efforts by Oregon’s U.S. Senators Ron Wyden and Jeff Merkley, who secured $800,000 in funding from the U.S. Environmental Protection Agency.

Research will focus in part on new ways to protect homes from smoke infiltration, along with more efficient communication with communities in emergencies and developing community action plans tailored to different regions in the Northwest.

The new Wildfire Smoke Research and Practice Center builds on research already completed through the Ecosystem Workforce Program (EWP), a joint venture between the UO and Oregon State University. KLCC reported that the EWP’s senior policy advisor Cass Moseley will head up the new center; she said recent incidents in the Pacific Northwest, particularly the 2020 Labor Day fires, highlighted the need for new smoke research. Much of Oregon, particularly the southern Willamette Valley, was choked with wildfire smoke for weeks during the 2020 fire season.

Those fires and the severe levels of smoke really emphasized the need for new research, according to Moseley. “And we saw this fall in Oakridge, several weeks of highly dense smoke as the fire there settled into that valley and really stayed; that community spent a lot of time and energy responding to that smoke event.”

Cedar Creek Fire, October 2022
Cedar Creek Fire Incident Command Post in Oakridge, Oct. 15, 2022 — Inciweb photo

The center’s launch was announced by Merkley and Wyden, who secured the funding to help communities prepare for wildfire smoke. One area of interest is the toxins released when manmade structures burn, as these risks became obvious during western Oregon fires in wildland/urban interface areas over the last few years. Most smoke research has focused on burning timber and wooden structures, and part of the new planned research will study effects of smoke from burning plastics, glass, fuels, and other synthetic materials. Moseley said the center has three co-investigators and a principal investigator leading the group, along with research assistants and graduate and undergraduate student assistants.

Joint Fire Science Program announces new funding for fuels treatment effectiveness

Funding for fuels research

Prescribed fire in Great Smoky Mountains NP
Prescribed fire in Great Smoky Mountains National Park, March 9, 2021. NPS photo.

The Joint Fire Science Program is offering grants for research into topics that can lead to more effective treatment of fuels. Examples include:

  • Longevity of fuel treatment effectiveness under climate change;
  • Fuels treatment effectiveness across landscapes;
  • Pre-fire management actions for reducing post-fire hazards; and
  • Social and political factors that influence fire suppression and rehabilitation costs.

The funding amounts for each of the four projects is expected to range from $300,000 to $500,000.

The new grant opportunities stem from the Bipartisan Infrastructure Law to advance research into wildfire prevention and post-fire restoration on federal lands.

The Joint Fire Science Program is accepting applications for grants to research innovative fuels treatments and post-fire rehabilitation efforts through Dec. 20, 2022, for fiscal year 2023.

Funding opportunities for wildland fire research priorities are posted on the Joint Fire Science Program’s website.

“With increasing wildfire activity due to climate change, it is imperative we fund research to better understand how to manage fire prone landscapes now and into the future,” said Grant Beebe, Bureau of Land Management assistant director of fire and aviation, based at the National Interagency Fire Center. “The Joint Fire Science Program brings the science and management community together in a unique, collaborative manner so that research can be used to make sound decisions on the ground.”

This funding is in addition to $3.4 billion in wildfire suppression and mitigation included in the Bipartisan Infrastructure Law.

This includes investments such as:

• $600 million to increase federal firefighter salaries by up to $20,000/year and convert at least 1,000 seasonal firefighters to year-round positions.
• $500 million for hazardous fuels mitigation.
• $500 million for prescribed fires.
• $500 million for communities to implement their community wildfire defense plan, a collaborative plan to address local hazards and risks from wildfire.
• $500 million for developing control locations and installing fuel breaks.
• $100 million for preplanning fire response workshops and workforce training.
• $40 million for radio frequency interoperability and to create Reverse-911 systems.
• $20 million for NOAA to create a satellite that rapidly detects fires in areas the federal government has financial responsibility.
• $10 million to procure real-time wildfire detection and monitoring equipment in high-risk or post-burn areas.

Researchers design model that they say predicts which buildings will survive wildfire

Wildfires may seem unpredictable, leaving random ruin in their wake. But it is based on science.

Coastal Fire, Orange County, CA
Coastal Fire, Orange County, CA, May 11, 2022. ABC7.

Six months ago we wrote about a project by the First Street Foundation which claimed to have developed a system for calculating the wildfire risk of 145 million properties in the United States.

We tested the system by entering property addresses for homes at two locations that were severely impacted by recent wildfires.

  • The Marshall Fire near Boulder, Colorado last year destroyed 1,091 homes and damaged 179. We looked up the Risk Factor for three properties in a community that had total destruction. The result was that they all had a 3 of 10 “moderate fire factor”, and individually a 1.84, 2.0, 1.84 percent chance of being in a wildfire over the next 30 years.
  • The Coastal Fire (see photo above) destroyed 20 homes in Laguna Niguel, California and damaged 11. The two we looked at in the zone with severe destruction received a 3 of 10 “moderate fire factor” with a 0.93 and 1.54 percent chance of being in a wildfire over the next 30 years. The homes were at the top of a steep brush-covered slope.

Another system

Colorado State University engineers have developed a model that they say can predict how wildfire will impact a community down to which buildings will burn. They say predicting damage to the built environment is essential to developing fire mitigation strategies and steps for recovery.

For years, Hussam Mahmoud, a Civil and Environmental Engineering professor, and postdoctoral fellow Akshat Chulahwat have been working on a model to measure the vulnerability of communities to wildfire. Most wildfire mitigation studies have focused on modeling fire behavior in the wildland; Mahmoud and Chulahwat’s model was the first to predict how a fire would progress through a community.

“We’re able to predict the most probable path the fire will take and how vulnerable each home is relative to the neighboring homes,” Mahmoud said. “We put a spin on the original model that allows us now to determine the level of damage in each building, whether the building will burn or survive.”

Using data from Technosylva, a wildfire science and technology company, Mahmoud and Chulahwat tested their model on the 2018 Camp Fire and 2020 Glass Fire in California. The model predicted which buildings burned and which survived with 58-64% accuracy. Since publishing their results in Scientific Reports, they have predicted which buildings burned with 86% accuracy for the Camp Fire by adjusting how the model weighs certain factors that contribute to damage.

Mahmoud says a holistic approach is needed to understand wildfire behavior and bolster resilience. Models that incorporate a community’s wildland and built environment features will give decision-makers the information needed to mitigate vulnerable areas.

Wildfire is like a disease

To develop their model, Mahmoud and Chulahwat employed graph theory, which is used to analyze networks. These methods also are used to study how diseases spread.

“Wildfire propagation in communities is similar to disease transmission in a social network,” Mahmoud said. Fire spreads from object to object in the same way contagions pass from one person to another.

Predicting survivability of structures in wildfire
Proposed relative vulnerability framework based on Degree ??? and Random walk ???? concepts implemented on (a) formulated graphs of the selected testbeds. (b) The modified degree formulation involves the following steps—(1) neighboring nodes identification, (2) Removal of low-impact connections from neighbors, and (3) Relative Vulnerability calculation. (c) The modified random walk formulation includes—(1) Generation of random walks of specific step length for each node, (2) Transmissibility calculation based on random walks generated, (3) neighboring nodes identification, (4) Removal of low transmissibility neighbors, and (5) Relative vulnerability calculation.

Wildfire mitigation strategies are like the tactics used to control the spread of COVID-19, he said. A community’s immune system can be boosted by mapping a structure’s surroundings (contact tracing), clearing defensible space around structures (social distancing), reinforcing structures to be more fire resistant (immunization), and creating a buffer zone at the wildland-urban interface (closing borders).

Some homes are like super-spreaders — they are more at risk of fire and more likely to transmit fire to other homes. By targeting certain homes or areas for reinforcement, policymakers could maximize a community’s mitigation efforts, Mahmoud said.

As wildfire risk is compounded by more people moving to wildland-adjacent areas and climate change drying out the landscape in arid regions, the researchers hope their model will help protect communities from the devastating losses wrought by wildfires.


“Fire science is not rocket science—it’s way more complicated.”
Robert Essenhigh, Professor Emeritus, Mechanical and Aerospace Engineering, Ohio State University.

Wildfire smoke alters immune cells, promoting inflammation

Smoke Beaver Fire
Smoke at the Beaver Fire in Northern California, August 12, 2014. Photo by Bill Gabbert.

Immune cells that normally protect against inflammation and infections can be altered by wildfire smoke to promote inflammation. A long list of diseases are associated with  inflammation. Studies have shown that healthy individuals and those with pre-existing conditions are affected by the very small PM2.5 particles produced by wildfire smoke.

forecast 4 a.m. PDT October 26 fire wildfire smoke
Forecast for the distribution of smoke at 4 a.m. PDT October 26, 2019 in the San Francisco area and south as far as Santa Maria.

Below are excerpts from an article written by Tori Rodriguez first published in Pulmonology Advisor. It covers the effects of smoke on humans and suggests what could be done to mitigate the potential damage. One idea is for fire and local officials when considering evacuation guidelines to plan for not only the dangers of flames, but also the effects of smoke.


[With wildfires increasing] and the health issues that result, there is a real and growing need for clinicians to educate at-risk patients, according to Jennifer Stowell, PhD, a postdoctoral researcher in the department of environmental health at the Boston University School of Public Health and co-author of a recent study on the health effects of wildfires.2 “For clinicians, education of patients is paramount, especially for those with already compromised health,” said Dr Stowell.

Healthy individuals may also experience health consequences from wildfires, according to Angela Haczku, MD, PhD, professor of medicine at the University of California, Davis, School of Medicine and director of the UC Davis Lung Center. “During the 2020 California wildfire season, my team conducted a study on healthy individuals and found alarmingly increased numbers of abnormal, activated immune cells in the peripheral blood.3 These cells are normally responsible for protecting against inflammation and infections, but when altered by inhalation of wildfire smoke, they become the ones promoting inflammation,” she explained.

Research exposes burning issues

The vast majority of recent US wildfires have been concentrated in western states, including Washington (218 fires), California (153 fires), Montana (141 fires), and Utah (130 fires).Estimates show that more than 70,000 wildfires have burned an average of 7 million acres in the US annually since the year 2000.4

In addition to this geographic damage, a sizeable body of research has detailed the negative human health effects resulting from exposure to wildfire smoke:

  • In a study published in June 2022, Heaney et al found that “smoke event” days —  those with the highest amounts of particulate matter 2.5 (PM2.5) from wildfires — were linked to increases in unscheduled hospital visits in California for all respiratory diseases (3.3%; 95% CI, 0.4%-6.3%) as well as asthma specifically (10.3%; 95% CI, 2.3%-19.0%), with the largest effect observed among children ages 0 to 5 years with asthma.2

Stratified analyses demonstrated increased visits for all cardiovascular diseases, ischemic heart disease, and heart failure among non‐Hispanic White patients and individuals older than 65 years. The findings further suggested that the interaction between wildfire PM2.5 concentrations and high temperatures may further increase the need for hospital visits among patients with cardiovascular disease.

  • A 2022 scoping review found evidence of increased population-level mortality, respiratory morbidity, and rates of various types of cancer in association with exposure to PM2.5 and chemicals from wildfire smoke.5
  • Findings from a 2021 study indicate that particulate matter from wildfire smoke has a greater effect on respiratory health than particulate matter from other sources of emission, based on a comparison of the increase in respiratory hospitalizations associated with increases in wildfire-specific PM2.5 (increase in hospitalizations ranging from 1.3% to 10%) and non-wildfire PM2.5 (increase in hospitalizations from 0.67% to 1.3%) in Southern California.6
  • Research published in 2021 showed that a 10 µg/m3 increase in wildfire PM2.5 was correlated with increased hospitalizations for all respiratory diseases, asthma, chronic obstructive pulmonary disease (COPD), and ischemic heart disease in Colorado. Wildfire PM2.5 was also associated with an increase in deaths due to asthma and myocardial infarction.7
  • Other results reported in 2021 linked wildfire PM.2.5 exposure in Alaska to elevated odds of asthma-related emergency department (ED) visits among various population, with odds ratios ranging from 1.10 (95% CI, 1.05-1.15) to 1.16 (95% CI, 1.09-1.23).8
  • A 2018 study analyzed data pertaining to 21,353 inpatient hospitalizations, 25,922 ED presentations, and 297,698 outpatient visits during periods of heightened smoke exposure from the 2007 San Diego wildfires. The results demonstrated a 34% increase in ED visits for respiratory diagnoses and a 112% increase in ED visits for asthma. Even greater increases in ED visits were observed among children aged 0 to 4 years with respiratory diagnoses  (73% increase) and in children aged 0 to 1 year with asthma (243% increase).9
  • Studies have also demonstrated increases in ED visits and hospitalization rates for asthma and other respiratory diseases in relation to wildfire PM2.5 in states such as Oregon and Nevada.10,11
  • Additionally, findings from multiple studies point to a potential connection between wildfire smoke exposure and higher rates of COVID-19 infection and associated mortality. In 1 study, researchers found that COVID-19 cases and related deaths increased by 56.9% and 148.2%, respectively, after the onset of the California wildfires that began in September 2020 compared with the period of time from the onset of the pandemic to just before the wildfires began.12
  • Results of another recent study suggest that “wildfire smoke inhalation sequesters activated, pro-inflammatory [natural killer] cells to the affected tissue compartments and may interfere with [COVID-19] vaccine effectiveness,” according to the authors.13

We interviewed Drs Stowell and Haczku to find out more about what clinicians need to know about the health effects of wildfires. Notably, Dr Haczku recently chaired the 2022 third annual NorCal Symposium on Climate, Health, and Equity.

“The size of the particulate matter is important….Particles larger than 10 micrometers in diameter are deposited in the nose, mouth, and upper airways, while PM2.5 is sucked directly down to the alveoli…causing disruption and inflammation.”
Dr Angela Haczku, Director of the University of California Davis Lung Center and chair of the 2022 NorCal Symposium on Climate, Health, and Equity.

What is known about the health effects of exposure to wildfire smoke?

Dr Stowell: Several studies have investigated the health effects of wildfire smoke and have linked smoke exposure to respiratory disease, cardiovascular disease, and birth outcomes such as preterm birth and low birth weight.14 Several gaps remain, including a better understanding of indoor air quality during wildfire events, the risk to outdoor workers, pregnancy complications, and mental health.

Dr Haczku: Wildfire smoke contains particulate matter of varying sizes, usually classified into PM10 and PM2.5 and ozone (O3) and nitrogen-containing toxic gases. All of these are combined with volatile organic chemicals that fuel the flames, the quality and quantity of which depend on whether what is burning comes from wild land, urban areas, or combined areas.

The size of the particulate matter is important because it determines where in the respiratory tract it will end. Particles larger than 10 micrometers in diameter (PM10) are deposited in the nose, mouth, and upper airways, while PM2.5 is sucked directly down to the alveoli, the tiny sacs responsible for our breathing, causing disruption and inflammation.

These particles are also carriers of inflammatory, allergenic, infectious, and toxic molecules causing both acute and chronic illnesses.

The most affected and best-studied organs susceptible to wildfire smoke are the respiratory tract and the cardiovascular system. Most ED visits are related to exacerbations of asthma and COPD and heart conditions such as coronary disease. Respiratory and cardiovascular mortality and hospitalization rates are well-known to be increased during wildfires. Affected adults and children also often suffer from anxiety and other mental health conditions. These conditions and the long-term health effects of wildfires are less studied and poorly understood.

What are the implications of these effects for health care systems?

Dr Stowell: Increasing wildfire activity due to climate change will continue to exacerbate these issues. Wildfire smoke exposure used to be thought of as an issue for the western US. However, as seen in the past several years, smoke from large fires and complex fires can reach across the continental US, exposing many individuals to harmful pollutants. Even with this wider spread of smoke, exposure will continue to have the greatest effect on the health of communities close in proximity to the fires, where smoke density is the heaviest.

Often the communities most affected are rural and face distance barriers to accessing proper health care. Thus, the health care systems in these already underserved areas could face capacity and response issues as wildfire smoke exposure continues to increase in western US states.

Dr Haczku: The effect of wildfire smoke on respiratory, cardiovascular, mental, and general health could be alleviated through specific interventions. As such, wildfire-related disasters provide health care systems with an opportunity to take a proactive role. Health care professionals should strategically and intentionally prepare for wildfire smoke events. Educational material should be prepared using professional society-approved guidelines and toolkits. These also need to be translated into the languages of and distributed to patients and potentially affected communities as well as the general public.

Having an efficient local system in place for timely warnings to reduce time spent outdoors during wildfire smoke events is crucial. Preventive measures in schools and indoor public places such as improved air filtration systems should be installed.

What are recommendations or considerations for clinicians to keep in mind when caring for patients in areas most affected by wildfires?

Dr Stowell: Education of patients is paramount. Some other steps could include considering temporary staff increases during wildfire seasons, ensuring the clinic staff are well-educated regarding wildfire smoke safety measures, and partnering with communities to provide clean air options for their patients.

Dr Haczku: In addition to intensive management of risk factors and chronic diseases, I believe implementing preventive measures are the most important. For example, professionals need to make sure that timely public warnings of smoke events are in place. Clinicians and health care workers should have a database that can be used to identify and reach out to vulnerable populations including pregnant women, children, the elderly, and farm and construction workers. Education of these communities and individuals can prevent emergency situations. Susceptible patients suffering from chronic illnesses and workers who cannot avoid outdoor activities may require help with fitting personal respirators and devices and specific consultation by health care workers.

What broader measures are needed to buffer the effects of wildfire smoke exposure and protect vulnerable populations, such as those with respiratory and cardiovascular diseases?

Dr Stowell: Much more needs to be done to plan for these large fire events. This planning includes focusing efforts in the areas most often affected by smoke through increasing health care system capacity, forming mobile health response teams, proper community education, better guidelines for evacuation (as most evacuations are intended to avoid the flames and not the smoke). Another need is access to clean air options, such as providing clean air centers and affordable access to air purification technology, including air conditioning and HEPA filtration.

Dr Haczku: As a health care educator, administrator, and climate change researcher, I see an urgent unmet need for the education of health care professionals about the effects of wildfires and, more generally, of climate change on human health. Vulnerable subjects, especially patients suffering from chronic health conditions, should be identified and educated. Improving advocacy toolkits and updating evidence-based professional guidelines for disease management and preventive interventions to reduce risk and protect health is imperative.

Research efforts to study and better understand wildfire smoke-induced pathologies as well as research to investigate the effectiveness of novel interventions should be better supported.

References

  1. Fire, Weather, and Avalanche Center. Current wildfires burning in the U.S. Accessed September 11, 2022.
  2. Heaney A, Stowell JD, Liu JC, Basu R, Marlier M, Kinney P. Impacts of fine particulate matter from wildfire smoke on respiratory and cardiovascular health in CaliforniaGeohealth. 2022;6(6):e2021GH000578. doi:10.1029/2021GH000578
  3. Teuber M, Flayer C, Linderholm A, et al. Wildfire smoke exposure activates circulating innate immune cellsJ Allergy Clin Immunol. 2021;147(2);Suppl_AB237. doi:10.1016/j.jaci.2020.12.012
  4. Congressional Research Service. Wildfire Statistics. Updated September 2, 2022. Accessed September 30, 2022.
  5. Grant E, Runkle JD. Long-term health effects of wildfire exposure: A scoping reviewJ Climate Change Health. 2022;6:100110. doi:10.1016/j.joclim.2021.100110.
  6. Aguilera R, Corringham T, Gershunov A, Benmarhnia T. Wildfire smoke impacts respiratory health more than fine particles from other sources: observational evidence from Southern California. Nat Commun. 2021;12(1):1493. doi:10.1038/s41467-021-21708-0
  7. Magzamen S, Gan RW, Liu J, et al. Differential cardiopulmonary health impacts of local and long-range transport of wildfire smokeGeohealth. 2021;5(3):e2020GH000330. doi:10.1029/2020GH000330
  8. Hahn MB, Kuiper G, O’Dell K, Fischer EV, Magzamen S. Wildfire smoke is associated with an increased risk of cardiorespiratory emergency department visits in AlaskaGeohealth. 2021;5(5):e2020GH000349. doi:10.1029/2020GH000349
  9. Hutchinson JA, Vargo J, Milet M, et al. The San Diego 2007 wildfires and Medi-Cal emergency department presentations, inpatient hospitalizations, and outpatient visits: An observational study of smoke exposure periods and a bidirectional case-crossover analysis. PLoS Med. 2018;15(7):e1002601. doi:10.1371/journal.pmed.1002601
  10. Gan RW, Liu J, Ford B, et al. The association between wildfire smoke exposure and asthma-specific medical care utilization in Oregon during the 2013 wildfire seasonJ Expo Sci Environ Epidemiol. 2020;30(4):618-628. doi:10.1038/s41370-020-0210-x
  11. Kiser D, Metcalf WJ, Elhanan G, et al. Particulate matter and emergency visits for asthma: a time-series study of their association in the presence and absence of wildfire smoke in Reno, Nevada, 2013-2018. Environ Health. 2020;19(1):92. doi:10.1186/s12940-020-00646-2
  12. Meo SA, Abukhalaf AA, Alomar AA, Alessa OM, Sami W, Klonoff DC. Effect of environmental pollutants PM-2.5, carbon monoxide, and ozone on the incidence and mortality of SARS-COV-2 infection in ten wildfire affected counties in CaliforniaSci Total Environ. 2021;757:143948. doi:10.1016/j.scitotenv.2020.143948
  13. Sanghar GK, Ravindran R, Teuber MJ, et al. Phenotypic evaluation of natural killer (NK) cells in response to BNT162b2 mRNA Covid-19 vaccine during wildfire smoke exposure. Presented at: the American Thoracic Society (ATS) 2022 International Conference; May 13-18, 2022; San Francisco, CA. Abstract A5407. doi:10.1164/ajrccm-conference.2022.205.1_MeetingAbstracts.A5047
  14. Evans J, Bansal A, Schoenaker DAJM, Cherbuin N, Peek MJ, Davis DL. Birth outcomes, health, and health care needs of childbearing women following wildfire disasters: An integrative, state-of-the-science reviewEnviron Health Perspect. 2022;130(8):86001. doi:10.1289/EHP10544