Examining the health impacts of short-term repeated exposure to wildfire smoke
Scope of Work
The objective of this project is to estimate the health effects (e.g., respiratory and cardiovascular diseases, hospitalization and emergency room visits) of short-term exposures repeated over days to weeks to wildfire-specific air pollution (e.g., hourly or daily variations, smoke wave) and to use this information to help educate communities and mitigate health risks in extreme events like wildfires. Updated estimates of health effects of short-term repeated exposure to wildfires will inform the California Air Resources Board’s (CARB’s) analysis of the health burdens from extreme events like wildfires. They will also help CARB estimate the impacts of policies meant to reduce the risk of wildfire and mitigate the impacts from smoke exposure.
CARB is mandated to protect the health of Californians, specifically disadvantaged communities that are most vulnerable to climate change impacts, which can include increased risk of wildfire. Extreme fires are a growing threat to public health and safety and degrade the quality of life in California with longer wildfire seasons and higher smoke exposures. Smoke from extreme fires can emit large amounts of air pollutants in a short time and travel long distances to affect the health of Californians. In the 2020 fire season, vast areas of the state experienced unhealthful air for days or weeks at a time. Wildfire smoke is a complex mixture of harmful air pollutants that is unhealthy to breathe and can be especially dangerous for sensitive groups (e.g., children, the elderly, pregnant women and people with pre-existing health conditions). Wildfires and the impacts of the smoke that they generate are particularly difficult for disadvantaged communities that have fewer resources and greater sensitivity to the health impacts from exposure to wildfire smoke. Particulate matter (PM) is the principal pollutant of concern from wildfire smoke for the relatively short-term exposures (hours to weeks) typically experienced by the public. Particles from smoke tend to be very small (with diameters of 2.5 micrometers and smaller, PM2.5) and can penetrate deeply into the lungs or can pass directly into the bloodstream.
While the associations between PM2.5 and heart and lung health effects are well documented in scientific studies, the direct health impacts of wildfire exposure are not as well established in scientific literature. Our current knowledge of wildfire smoke health effects is based largely on two different streams of research: 1) PM2.5 effects determined from epidemiological research on the short- and long-term health effects of chronic PM2.5 exposure; and 2) recent studies that have found increased respiratory and cardiac symptoms in people living near wildfire events. However, there has been insufficient attention to studying the effects of repeated exposures to short but intense levels of wildfire smoke as experienced in California in the 2020 fire season.
In 2017, Liu et al. published a study that investigated the direct health effects of exposure to wildfire-specific PM2.5 in the Western United States. Liu et al. proposed a new idea called a smoke wave to define exposure to an extreme event like wildfires using consecutive days with daily exposures over certain defined levels of wildfire-related pollution. This idea of a smoke wave can be used to detect the impacts of the extremely high exposures due to wildfires when most of the days without wildfires have lower exposure levels. The study found that an increased risk of respiratory hospital admissions was linked to severe smoke wave days, while there were no significant associations between cardiovascular effects and smoke wave days. While this research and previous studies have observed inconclusive results for wildfire smoke exposure and cardiovascular diseases, newer studies (including Wettstein et al.’s) are finding a significant impact of wildfire smoke on cardiovascular emergency department visits. Therefore, CARB would like investigators to build on the “smoke wave” characterization of exposure and to estimate its potential health effects, such as both respiratory and cardiovascular diseases.
California’s natural and working lands provide important and significant environmental and public health benefits to the State and are often the first to experience the impacts of climate change. CARB has been developing programs and policies to reduce and provide solutions to worsening climate change impacts, including those in natural and working lands. Given the hotter and drier weather in California and the impacts of climate change, longer-term and larger wildfires are expected to continue and a project that updates the estimates of health impacts of sub-chronic exposure to wildfires is needed. While there are recent studies of health effects linked to individual wildfire events, this study is envisioned to be a larger-scale (statewide or multiple regions of the state) and multi-year study that will evaluate respiratory and cardiac symptoms across different events and different durations of smoke exposure in the sub-chronic category. The results of this project will better inform CARB’s analysis of the health burdens from extreme events like wildfires which negatively impact public health and degrade the quality of life in California. This research would help inform messaging and outreach efforts designed to help the public better understand the impacts of smoke and how to protect themselves from it.
Scope of Work
The investigators will examine direct health impacts of wildfire exposure using a retrospective, large-scale (e.g., statewide or multiple regions of the state) and multi-year epidemiological study design. State-of-the-art techniques should be applied to model wildfire-specific air pollution concentrations with fine spatial resolution so that results can be estimated at the census tract level or smaller area. The expected health outcomes to be analyzed for participants include (but are not limited to) asthma exacerbations, medication use, hospitalizations, and physician/emergency department visits for respiratory and cardiovascular diseases. Other health effects such as total hospitalizations, emergency department visits, and adverse birth outcomes should be considered if possible. The study should specifically include impacts in disadvantaged communities and vulnerable groups (e.g., children, elderly populations, pregnant women, racial and ethnic groups and those living in poverty). It is preferable for the study to consider both urban and rural locations, and to also include tribal communities. Moreover, estimating effects of chemical compositions of wildfire-specific particulate matter and/or different types/species of wildfires (e.g., wildfire in forests, grasslands, and structural fires) is encouraged. The study should also estimate health-related economic impacts of exposures to wildfire-specific air pollutants.
At the end of this study, CARB will expect new information on as many of the following health outcomes as possible, including respiratory and/or cardiovascular disease symptom increase, medical facility use, medication use, increased incidence of morbidity and mortality, or possibly birth outcomes (including low birth weight and preterm birth). The study should demonstrate the link between the specific health outcomes and exposure periods that may be defined as hours, days or weeks of exposure. The researchers should also include information on mitigation measures available to reduce or avoid health impacts. The results of this project will be useful in quantifying the more complete health impacts of CARB policies and would help inform the full impact of policy decisions of CARB to protect public health.
Task 1. Conduct a literature review
The investigators will conduct a comprehensive literature review on recent research that examines direct health impacts of short-term exposures to wildfire-specific air pollution. The research may include epidemiological and animal studies and be conducted in California and Northern America. A gap in previous research should be identified.
Task 2. Model exposure to air pollution
The investigators will model wildfire-specific air pollution concentrations with fine spatial resolution using state-of-the-art techniques so that results can be estimated at the census tract level or smaller area. Short-term exposures should be estimated by hourly or daily variations and smoke wave. The estimation of exposure data in a large domain (e.g., statewide or multiple regions of the state) and across multiple years (e.g., 2017-2020) is envisioned. The targeted air pollutants should include PM2.5 and other pollutants (e.g., PM10, volatile organic compounds) are desired and encouraged. Investigators should include estimates of chemical compositions of wildfire-specific PM2.5 and/or different types/species of wildfire-specific PM2.5 (e.g., the First Order Fire Effects Model, FOFEM) if possible. Additionally, the investigators should consider the exposure profiles previously developed by other CARB funded projects to see if these are applicable.
Task 3. Obtain health data and covariates
The investigators will obtain population data from available datasets on health outcomes such as the following: asthma exacerbations, medication use, hospitalizations and physician/emergency department visits for respiratory and cardiovascular diseases. Additional adverse health effects (e.g., total hospitalizations and emergency department visits and adverse birth outcomes) can be considered. Covariates and/or confounding factors identified in previous research need to be included. Health and covariate datasets should have a resolution as high as possible to align with exposure data layers (i.e., similar spatial alignment).
Task 4. Link exposure to health impacts
The investigators will conduct advanced statistical analyses to estimate the health impacts of exposure to wildfire-specific air pollution (e.g., comparing prevalence/incidence of adverse health outcomes between exposed and non-exposed groups, estimating dose-response curves, developing relative risks). In addition to overall estimation, the investigators will specifically conduct analyses for subgroups, including disadvantaged communities and vulnerable populations; analyses for urban/rural locations and tribal communities are encouraged. Lastly, the investigators should control confounding factors, perform sensitivity analyses (e.g., lag time, cut-off points for exposure, length of smoke wave), and test statistical validity. If possible, investigators could include a follow-up period to estimate lagged health effects from the wildfires that persist after the direct wildfire exposures are ended.
Task 5. Address impacts in disadvantaged communities
The investigators will address specific concerns for disadvantaged communities, including AB 617 communities and vulnerable groups. The investigators will meet with members of multiple communities most affected by smoke impacts before the study begins to explain how the study will be conducted (such as the collection and analyses of data) and provide an opportunity for community members to express their ideas on the study, including the study goals and design, to see if modifications can be made to make the study more informative for the community. The investigators will also meet with community members in the same areas at the end of the study to communicate and interpret results and discuss possible next steps. Input and concerns from affected communities can also be collected through workshops and other communication avenues such as surveys. Community expertise and feedback will be incorporated into the analysis and final report. It is preferable for the study to consider both urban and rural locations, and to also include tribal communities.
Task 6. Reporting and data delivery
The investigators will submit quarterly progress reports, a draft final report and final report to CARB, participate in progress update meetings and a seminar at the conclusion of the project. The investigators will provide raw data, modeled data, and all data analyses results generated through the course of the project in electronic format. Additionally, the investigators will prepare peer-reviewed journal articles as appropriate and provide a preview of the manuscript to CARB for their comments prior to submission. Submitting articles to open-access journals is recommended. Lastly, CARB requires new research contracts to incorporate equity components in the deliverables (see details in IV. DELIVERABLES).
Beginning this fiscal year, 2021-2022, CARB’s Research Division (RD) will require its contracted research projects to embody racial equity components. The newly instituted initiative calls for all RD contracted projects to adopt racial equity components into their research. In light of this commitment to advance racial equity in research, RD will work closely with contractors to not only increase solicitation awareness, but also find opportunities to connect researchers with non-academic partners. Moving forward, RD staff will work with multiple interested stakeholders to develop additional racial equity components that reflect the policies, programs, and interests of CARB to achieve equitable and healthy sustainable community strategies that meet California’s climate goals. The following project deliverables include equity components:
- Quarterly progress reports and conference calls including public facing updates posted to CARB website;
- Meetings in smoke-affected communities to discuss study methodology and results;
- Consultation calls with CARB and key stakeholders;
- Data on as many of the following health outcomes as possible linked to wildfire smoke waves: respiratory and/or cardiovascular disease symptom increase, medical facility use, medication use, increased incidence of morbidity and mortality, or possibly birth outcomes (including low birth weight and preterm birth). Also, provide all data, analyses and analytical tools generated through the course of this project;
- Draft final report;
- Final report and in-person or virtual seminar (pending health requirements);
- Prepare peer-reviewed journal articles as appropriate and provide a preview of the manuscript to CARB for their comments prior to submission;
- Encourage non-academic partners, such as non-profits or community advocates; and/or encourage academic partners new to CARB contracting and/or from smaller universities;
- All researchers must undergo a cultural competency training (examples include implicit bias training, racial equity training, etc.) and provide a cultural competency statement in the proposal;
- Peer reviewed publications should be publicly available (please budget for this expense);
- Work with CARB to create plain-language outreach deliverables for the public (available in multiple languages and formats);
- Additional deliverables to be determined in consultation with CARB staff.
It is anticipated this project will be completed in 24 months from the start date. This allows 18 months for completion of all work through the delivery of a draft final report. The last 6 months are for review of the draft final report by CARB staff and the Research Screening Committee (RSC), modification of the report by the contractor in response to CARB staff and RSC comments, and delivery of a revised final report and data files to the CARB. The estimated budget for this project is $500,000.
In order to increase transparency of how winning pre-proposals are chosen, scoring criteria have been included for each project. Please note that scoring criteria is tailored to each project included in CARB's fiscal year 2021-2022 solicitation. If you are submitting pre-proposals for more than one project in the solicitation, please be sure to review the scoring criteria to get a better understanding of what components of the project are most valued for selection.
- Responsiveness to the Goals and Objectives Outlined in the Proposal Solicitation(15 points) Proposers should demonstrate a clear understanding of the policy objectives and research needs that CARB seeks to address with this project, and should convey their knowledge of the subject. The proposal should spell out, in adequate detail, exactly what the Proposer proposes to do to satisfy the requirements of the Solicitation. The draft proposal must propose work that would satisfy the objective(s) stated in the Research Solicitation: to estimate the health effects of short-term exposures repeated over days to weeks to wildfire-specific air pollution Click here to enter text.
- POLICY RELEVANCE/BENEFITS TO THE STATE(10 points) – Does the proposal describe how the project will provide data, information, and/or products to help CARB accomplish its mission? Results of this project should inform CARB’s analysis of the health burdens from wildfires and help CARB estimate the impacts of policies meant to reduce the risk of wildfire and mitigate the impacts from smoke exposure.
- PREVIOUS WORK (10 points)
- ACADEMIC EXPERTISE (5 points) - Do the researchers have relevant experience in this area? Do they discuss how they will build upon previous relevant work that was funded by CARB, other state agencies, and federal agencies such as US EPA, NSF, or NIH?
- EXPERIENCE AND PROVEN DEDICATION TO COMMUNITY BASED ENGAGEMENT APPROACHES (5 points) - Does the proposal discuss previous experience with community engagement? Do the researchers describe previous experience in community engagement and provide letters of support, references, or a community impact statement, describing how previous work impacted communities?
- EXPANDING EXPERTISE (10 points) – Does the team bring in new talent that has not worked with CARB previously? Is the team composed of a multidisciplinary team of experts? Researchers new to CARB are encouraged to apply and partner with multidisciplinary teams.
- TECHNICAL MERIT (25 points) - Describe the submission's technical strengths and/or weaknesses. Proposers should demonstrate the logic and feasibility of the methodology and technical approach to the project, spell out the sequence and relationships of major tasks, and explain methods for performing the actual work. Please factor in how well the draft proposal describes these areas:
- A large-scale and multi-year epidemiological study design
- State-of-the-art techniques for modeling wildfire-specific air pollution with fine spatial resolution
- Relevant health outcomes, sufficient covariates, and a large enough sample size for the health data to achieve adequate statistical power at the spatial resolution used in the study
- Advanced and appropriate statistical approaches, including sensitivity analyses and validity tests
- Specific analyses for disadvantaged communities and vulnerable groups
- The review team will be selecting only one draft proposal for development into a full proposal. If this draft proposal has potential, what areas or topics should be prioritized or better explained in the full proposal?
- LEVEL AND QUALITY OF EFFORT TO BE PROVIDED(15 points) – Does the proposal allocate time and resources in such a way that the objectives of the study will be met? Is supervision and oversight adequate for ensuring that the project will remain on schedule? Is the distribution of workload appropriate for activities such as research, evaluation and analysis, data reduction, computer simulation, report preparation, meetings, and travel? If pre-existing datasets are used are these available in a timely manner and at the spatial resolution needed?
- COST EFFECTIVENESS (15 points) - Does the cost seem appropriate for the proposed work? Does the proposed work seem feasible within the requested budget? Projects that provide co-funding should be evaluated more favorably.
 Liu JC, Wilson A, Mickley LJ, et al. Wildfire-specific Fine Particulate Matter and Risk of Hospital Admissions in Urban and Rural Counties. Epidemiology. 2017;28(1):77-85. doi:10.1097/EDE.0000000000000556
 Reid CE, Brauer M, Johnston FH, Jerrett M, Balmes JR, Elliott CT. 2016. Critical review of health impacts of wildfire smoke exposure. Environ Health Perspect 124(9):1334–1343, PMID: 27082891, https://doi.org/10.1289/ehp.1409277.
 Wettstein ZS, Hoshiko S, Fahimi J, Harrison RJ, Cascio WE, Rappold AG. Cardiovascular and Cerebrovascular Emergency Department Visits Associated With Wildfire Smoke Exposure in California in 2015. J Am Heart Assoc. 2018 Apr 11;7(8):e007492. doi: 10.1161/JAHA.117.007492. PMID: 29643111; PMCID: PMC6015400.