Living Under Smoky Skies—Understanding the Challenges Posed by Wildfire Smoke in California

Living Under Smoky Skies— Understanding the Challenges Posed by Wildfire Smoke in California GABRIEL PETEK | LEGISLATIVE ANALYST NOVEMBER 2022 AN LAO REPORT ii LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT Executive Summary In this report, we (1) summarize trends in wildfires and associated smoke; (2) review research on the health and other effects of wildfire smoke, including on vulnerable groups; (3) discuss local, state, and federal roles and responsibilities related to smoke, as well as actions that the state currently is undertaking to address it; and (4) provide some guidance to the Legislature as it formulates its approach to addressing smoke in the coming years. Wildfire Smoke Is a Significant and Growing Concern. Californians have been exposed to more large, high-severity wildfires in recent years. These wildfires have generated more smoke and greater emissions of various pollutants. Notably, the trend of growing wildfire smoke is anticipated to continue. Experts expect the state will experience more large and intense wildfires in coming years, fueled by a combination of climate change and decades of poor forest management. Additionally, some of the state’s efforts to reduce the likelihood of these large and often destructive wildfires—such as through planned, controlled fires known as prescribed fires— while critical, will also generate smoke. Accordingly, Californians likely will have to adjust to living with higher levels of smoke than they have experienced in recent decades. Wildfire Smoke Has a Wide Range of Negative Effects. The increase in wildfire smoke is of concern because it can have a wide range of negative health and other impacts. For example, wildfire smoke is associated with increases in emergency department visits for respiratory conditions such as asthma, as well as increases in mortality. Also, the adverse effects of wildfire smoke are not uniformly distributed across individuals, households, and communities. Instead, certain populations, such as those who are older or have underlying health conditions, tend to be more vulnerable to the negative effects of smoke. Individuals and Governments Can Take Actions to Mitigate the Impacts of Smoke. Various activities, such as remaining indoors and running a portable air purifier, can help mitigate the effects of wildfire smoke. However, people face barriers that may not always make it possible for them to take such actions. In practice, individuals may not always know when smoke levels are elevated or what steps they should take. Additionally, even if they do have this information, it is not always feasible for everyone, particularly those with limited resources, to undertake actions to protect themselves. Notably, government agencies—at the state level, as well as at the local and federal levels—currently are undertaking a variety of activities to help address the effects of wildfire smoke and mitigate barriers. For example, state agencies are expanding their efforts to disseminate information about smoke events and piloting the use of clean air centers to serve as locations for people to avoid wildfire smoke. Legislative Considerations for Building on Existing Efforts. Given the significant health and other impacts of wildfire smoke—particularly on those who are vulnerable due to their age, health status, or socioeconomic factors—the Legislature may want to consider what additional steps, if any, it would like to take to build on existing efforts. A few examples of the types of steps that the Legislature could consider taking include: supporting additional research and pilot projects to improve understanding of the best and most cost-effective approaches to address wildfire smoke; providing targeted funding for mitigations, such as purchasing portable air purifiers; or supporting efforts to improve information dissemination. Notably, another approach the state could take is to support expansions of prescribed burning. This is because, while prescribed www.lao.ca.gov 1 AN LAO REPORT burns generate some smoke, they reduce the risk of large, severe wildfires, which typically produce the most dangerous and impactful smoke. Some key criteria for the Legislature to consider as it chooses among these and other available options include: (1) whether the state is the appropriate entity to undertake the activity, (2) whether there is a demonstrated need for the activity, (3) the strength of the evidence of the activity’s cost-effectiveness, (4) the extent to which the activity targets vulnerable groups, and (5) the co-benefits that the activity provides beyond reducing the impacts of smoke. 2 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT INTRODUCTION Smoke Is a Growing Concern of Statewide fires to refer to all fires that affect wildlands, Importance. The state has made significant strides including both wildfires and prescribed fires.) in recent decades toward improving its air quality This report is intended to be a first step aimed by reducing emissions from both stationary and at assisting the Legislature as it considers what nonstationary sources (such as fossil-fuel power additional state actions might be warranted to plants and vehicles). However, these improvements mitigate the impacts of this smoke, particularly have been offset to some degree by a growing on the Californians who are most vulnerable to source of poor air quality: smoke from wildfires. its effects. In recent years, wildfire smoke emissions have This report has four main sections. First, we trended upward and become a major contributor to summarize trends in wildfires and associated air pollution in California. smoke, describing how Californians have been Notably, the trend of growing wildfire smoke is exposed to more smoke and associated pollutants anticipated to continue. Experts expect the state in recent years and why this trend is anticipated will experience more large and intense wildfires in to continue. Second, we review research on the coming years, fueled by a combination of climate health and other effects of wildfire smoke, including change and decades of poor forest management. on vulnerable groups. Third, we discuss local, Additionally, some of the state’s efforts to reduce state, and federal roles and responsibilities related the likelihood of these large and often destructive to smoke from wildland fires, as well as actions wildfires—such as through planned, controlled fires that the state currently is undertaking to address known as prescribed fires—while critical, will also this smoke. Notably, some types of actions to generate smoke. Accordingly, Californians likely will address smoke lend themselves to a state role, have to adjust to living with higher levels of smoke while others are more appropriately taken by other than they have experienced in recent decades. entities. Finally, in the fourth section of this report, This Report Describes Challenges Posed we provide some guidance to the Legislature as by Smoke From Wildland Fires. This report is it formulates its approach to addressing wildland intended to help the Legislature and the public fire smoke in the coming years. The report also deepen their understanding of the challenges that includes an Appendix, which lists the key studies smoke from wildland fires poses for the state. referenced throughout the text. (Throughout this report, we use the term wildland WILDFIRE SMOKE TRENDS AND COMPONENTS Below, we discuss how Californians have been Californians Have Been Exposed to exposed to more large, high-severity wildfires in More Smoke in Recent Years recent years, which have generated more smoke State Has Experienced Growing Number of and greater emissions of various pollutants. Large, High-Severity Wildfires. In recent years, We also discuss how Californians may need to California has experienced an increasing number adapt to higher levels of smoke because climate of large wildfires. Notably, 12 of the 20 largest change is likely to increase the threat of large and wildfires in the state’s recorded history—as intense wildfires and because the state will need measured by the number of acres burned—have to step up its efforts to reintroduce controlled, occurred within the last five years. As shown in typically low-severity fires into wildland areas, which will also generate some smoke. www.lao.ca.gov 3 AN LAO REPORT Figure 1, recent wildfires not only have affected discussed elsewhere in this report.) Second, climate large areas but also have burned significant change has contributed to hotter weather and acreage at high severity. (The severity of a fire is longer dry seasons in California than was previously determined based on various factors, including typical. These conditions have increasingly dried the share of various types of vegetation—such out vegetation and lengthened the wildfire season, as tree crowns—that are burned.) High-severity which has increased fire risks. Additionally, climate wildfires often denude landscapes, leaving large change has negatively affected forest health by areas with mostly charred remnants. In contrast, increasing the frequency and severity of droughts, lower-severity wildfires typically burn underbrush which put stress on trees and make them more and smaller trees, but leave intact many larger, susceptible to pest infestations. This, in turn, has well-established trees and species that have led to more diseased, dead, and dying trees, which adapted to withstand fire. also have exacerbated the severity of wildfires by Growth in Severe Wildfires Driven by Two providing more combustible fuels. Main Factors. Two key reasons explain the Wildfires Generating Growing Amounts of increase in large, high-severity wildfires in California Smoke. In part due to their size and severity, in recent years. First, many of the state’s forestlands recent wildfires have generated large amounts have become unhealthy, in part due to the focus on of smoke that have affected significant portions suppressing naturally occurring fires over the past of the state, sometimes for extended periods. As century. As shown in Figure 2, these forestlands shown in Figure 3 on page 6, major cities across are densely filled with relatively small trees and the state experienced significantly more days of brush, which serve as “ladder fuels” to carry smoky air—days on which smoke was observed wildfires into tree canopies, thereby increasing their via satellite imagery—between 2016 and 2020 spread and intensity. (The figure also shows how compared to between 2009 and 2013. (Smoke days these more severe wildfires generate additional may not always be obvious to residents, but can be smoke and often leave landscapes denuded, as observed by satellite and still have potential health Figure 1 California Wildfires Growing Increasingly Severe Acres Burned by Severitya (In Millions) 4.0 3.5 High Severity 3.0 Moderate Severity Low Severity 2.5 2.0 1.5 1.0 0.5 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 2015 2017 2019 a The severity of a fire is determined based on various factors, including the share of various types of vegetation—such as tree crowns—that are burned. Definitions of low-, moderate-, and high-severity wildfires can be found at https://burnseverity.cr.usgs.gov/glossary.(cid:31) Data Source: Monitoring Trends in Burn Severity data provided by U.S. Forest Service. 4 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT impacts, as discussed later in this report.) Notably, Pollutant of Greatest Concern Is Fine as we discuss further in the box on the next page, Particulate Matter. Of the various air pollutants in while smoke levels over the past few years have wildfire smoke, the one that is generally considered been higher than in the recent past, smoke from to be of greatest concern is fine particulate matter wildland fires likely was much more prevalent before of2.5 microns in diameter or less, known as PM . 2.5 European settlement and the advent of modern The small size of PM —roughly 1/30 or less of the 2.5 fire suppression. In particular, starting in the early width of a human hair—contributes to its ability to 1900s, government policy emphasized suppressing negatively affect people in a few notable ways. First, all fires (often referred to as “fire exclusion”). This PM can remain suspended in the air for extended 2.5 reduced the acreage burned and associated periods. This, in turn, enables PM to travel further 2.5 emissions, but also has contributed to the poor forest health that exists across the state today. Figure 2 Smoke Pollutants Have Forest Health Affects Severity of Wildfires and Smoke Contributed to Worsening Air Quality Unhealthy Forest Healthy Forest Wildfire Smoke Contains Various Pollutants. The increase in smoke from wildfires raises concerns due to the various pollutants such smoke can contain, such as particulate matter, ozone, volatile organic compounds, carbon monoxide, nitrogen oxide, Dense trees and brush, comparatively Sporadic trees and brush, comparatively and trace metals. Importantly, the more small and young trees. more large and old trees. composition of smoke can vary across wildfires. This is because the types and quantities of air pollutants depend on a variety of factors, such as the intensity of the wildfire, the type of fuels that burn, and the dryness of the fuels. For example, smoke from wildfires that burn structures can contain higher Larger, more intense wildfires generate Smaller, less intense wildfires generate more smoke. less smoke. levels of certain contaminants, such as lead, than would be typical when fires only burn vegetation. Notably, smoke from a single wildfire can also change over time depending on the type and condition of the vegetation and other materials that burn, as well as how the resulting smoke is dispersed geographically by weather and Little vegetation remains after wildfire. Some vegetation remains, including atmospheric conditions. larger trees and fire-adapted species. www.lao.ca.gov 5 AN LAO REPORT from wildfire activity than coarser Figure 3 matter would, sometimes leading it to affect communities hundreds of Wildfire Smoke Exposure in California Cities miles away from an active wildfire. Has Increased in Recent Years Second, PM ’s small size allows it 2.5 to infiltrate indoor spaces relatively 10 20 30 40 50 easily, particularly those spaces Sacramento that are not well-sealed (such as older, drafty houses). Third, PM ’s Fresno 2.5 size also facilitates its travel deep Oakland into the respiratory tract, as well as into the bloodstream, where it can San Jose trigger negative health impacts. (We discuss these health effects, San Francisco as well as other impacts of PM , 2.5 Los Angeles in further detail later in this report.) Average Number of Smoke Days Per Yeara Wildfire Smoke Having Long Beach 2009-2013 Growing Impacts on State’s 2016-2020 San Diego Air Quality. Recently, estimated emissions of PM 2.5 from California wildfires have a Days in which smoke was observed on satellite imagery. generally trended upward as Source: Romero, Farida Jhabvala, et al. (2021). the state has experienced more smoke from large wildfires. Wildland Fire Smoke Prevalent Before European Settlement Wildland Fires Burned Large Areas Before Modern Fire Exclusion Policies. Wildland fires are a natural part of California’s ecosystems. Historically, significant parts of the state would burn annually, especially during the warm, dry months of the year. In the 1700s, for example, an estimated 4.5 million acres burned each year, on average. This is more than four times the average annual amount of acreage that has burned in recent decades, due in large part to the state’s focus on suppressing wildfires. Some of the fires during the period before European settlement were intentionally set by Native American tribes for ecological, ceremonial, and other cultural purposes, while other fires were ignited without human intervention (such as by lightning strikes). These Wildland Fires Generated Large Amounts of Smoke. These large fires that were left to burn hundreds of years ago generated significant amounts of smoke. A 2007 study points out that before European settlement and the introduction of modern fire suppression, smoke likely filled the skies in California during much of the summer and fall. Significant uncertainty exists regarding the level of emissions generated by these fires. For example, this study suggests that wildfires in California generated between 474 and 1,281 gigagrams (Gg) of PM annually prior 2.5 to 1800. (PM refers to fine particulate matter of2.5 microns in diameter or less.) As a point of 2.5 comparison, the California Air Resources Board estimates that wildfires in the recent severe fire years of 2018 and 2020 emitted roughly 380 and 1,070 Gg of PM , respectively. Excepting those 2.5 two severe years, wildfires between 2011 and 2020 emitted an average of roughly 136 Gg of PM 2.5 annually. Thus, recent decades of relatively little smoke—driven by policies of fire exclusion—are likely well below the historical norm. 6 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT As shown in Figure 4,the average estimated recent years in California. This trend has also annual PM from wildfire smoke was significantly been documented in the larger western region. 2.5 higher across much of the state in the seven For example, one 2021 estimate found that years ending in 2020 than it was during the wildfires account for up to half of small particulate prior seven years (2007 through 2013). Over this matter in parts of the Western United States, period, emissions of PM from other sources compared to less than 20 percent a decade ago. 2.5 generally have declined, largely due to various Impact of Wildfire Smoke on Air Quality Is regulatory policies. Accordingly, wildfire smoke Episodic. While wildfire smoke has become a has contributed a growing share of PM in more significant contributor to overall air quality 2.5 Figure 4 Most of State Has Experienced Large Increases in Wildfire-Driven Air Pollution Percentage Increase in Estimated Average Annual PM From Wildfires Between 2007-2013 and 2014-2020 2.5 Less than 100 percent 101-200 percent 201-300 percent 301-400 percent Greater than 400 percent Prepared using data from Childs, Marissa L., et al. (2022). PM2.5 = fine particulate matter of 2.5 microns in diameter or less†. www.lao.ca.gov 7 AN LAO REPORT than it was a decade ago, annualized data do not and associated particulate matter emissions in the fully capture how such smoke affects air quality. future is subject to uncertainty. However, one 2016 This is because emissions from wildfires, unlike study estimates that average emissions of PM in the 2.5 many other sources of pollutants, are not spread Western United States from wildfires could increase out evenly throughout the year. Instead, since by more than 60 percent by mid-century (compared wildfires are episodic, they produce smoke and to 2004 through 2009) and maximum PM emissions 2.5 associated emissions intermittently. Accordingly, from wildfires could increase by close to 400 percent. during some periods of a given year, wildfires Greater Use of Prescribed and Other Beneficial contribute very little to emissions, while at Fire Also Will Generate Smoke. As discussed other times they might be very large factors. above, along with climate change, another contributor Importantly, when the air quality in the state to the growth of large, severe wildfires has been the is very poor, wildfires are often an important poor condition of many of the state’s forests and contributor. For example, a 2016 study estimated wildlands. In the coming years, the state will need to that wildfires contributed an average of over accelerate its efforts to better steward these lands— 70 percent of total daily PM in the Western such as by removing some of the excess vegetation 2.5 United States on days that exceeded federal that has accumulated—to improve their health and regulatory standards, compared to an average resilience to wildfires. A key component of the state’s of 12 percent of total daily PM over the course strategy to accomplish these improvements is to 2.5 of the entire study period from 2004 to 2009. reintroduce a greater level of ongoing, controlled This temporal characteristic of wildfire smoke is fire onto landscapes across the state. This includes important because the health impacts of relatively expanding the use of prescribed fire by the state and short-term, very high levels of pollutants such as its partners. The state also is seeking to facilitate more PM could potentially differ from the impacts of cultural burning by Native American tribes and greater 2.5 prolonged, lower levels of pollutants. This is the use of managed wildfires by the federal government. case even if average levels of exposure across a These types of fire, which together are sometimes given period of time are the same. referred to as beneficial fire, help remove surface fuels, thin forests, and burn lower branches to lift tree Californians Likely Will be Exposed to canopies. Notably, in total, California’s Strategic Plan More Smoke From Wildland Fires for Expanding the Use of Beneficial Fire calls for the in Future state and federal governments and their partners to Trend of Increasing Large and Severe Wildfires increase the use of beneficial fire to 400,000 acres Likely to Continue. As mentioned previously, per year by 2025. (For context, based on information climate change has already contributed to more in the Strategic Plan, we estimate that between 2017 frequent large, severe wildfires. This trend is generally and 2020, these entities used beneficial fire on over anticipated to continue as the state experiences 100,000 acres annually.) Beneficial fire is important more of the impacts of climate change, such as for returning landscapes to more natural, healthy increased average temperatures and more frequent conditions, but will inevitably result in some smoke and and prolonged droughts. Importantly, the degree to associated emissions. which climate change will increase wildfire activity EFFECTS OF WILDFIRE SMOKE In this section, we summarize the growing body communities. Instead, certain populations of people, of research on impacts to physical health and other such as those who are older or have underlying effects of wildfire smoke. We also summarize how the health conditions, tend to be more vulnerable to the adverse effects of wildfire smoke are not uniformly effects of this smoke. distributed across individuals, households, and 8 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT Wildfire Smoke Associated With Wildfire Smoke Also Linked to Economic and Numerous Negative Effects Other Impacts. The most widely studied effects of wildfire smoke have been related to physical Wildfire Smoke Associated With Various health conditions. However, emerging research Negative Physical Health Impacts. A growing links wildfire smoke to other negative outcomes. body of research links wildfire smoke to negative For example, one 2022 study found a relationship effects on human physical health and to increases between wildfire smoke levels and poorer cognitive in mortality. We highlight some key examples of this performance on a brain-training game, and another research in Figure 5. As shown in the figure, much 2022 study found a link between smoke exposure of this research explores the association between and lower test scores. A third 2022 study revealed exposure to wildfire smoke and associated emissions links between estimated exposure to smoke from of particulate matter, and measures of use of medical wildfires and various labor outcomes, including care (such as hospital admissions or emergency lower income, employment, and labor force department visits). The most well-documented, participation. Specifically, the study estimated that consistent relationship is between wildfire smoke and wildfire smoke reduced nationwide earnings from respiratory conditions, such as asthma. Evidence jobs by an average of close to 2 percent per year also exists—although generally is somewhat (the equivalent of $125 billion annually) between less consistent—connecting wildfire smoke to 2007 and 2019. These studies are not without cardiovascular effects, such as heart attacks. Some their limitations. For example, participants in the research also finds associations between exposure to wildfire smoke and birth outcomes, such as the likelihood of preterm Figure 5 birth. (Preterm births are associated Findings From Recent Research on with higher risks of various long-term health problems.) Additionally, Physical Health Effects of Wildfire Smoke evidence not only links wildfire smoke to health conditions, but also Respiratory Effects • Several studies have found associations between wildfire smoke and increases in to a greater risk of death. emergency department visits for respiratory diseases, such as asthma (Malig, et al., Notably, the overall health 2021; Wettstein, et al., 2018; Alman, et al., 2016; and Rappold, et al., 2011). • Recent research has also linked smoke to increased asthma diagnoses at emergency effects of wildfire smoke still are departments, office visits, and outpatient visits, as well as an increase in inhaler medication refills (Gan, et al., 2020). being studied and some key gaps in research still exist. For example, Cardiovascular Effects most existing research focuses • Several studies have found links between wildfire smoke and increases in emergency on linking specific, short-term department visits for cardiovascular reasons, such as heart attacks (Malig, et al., 2021; Wettstein, et al., 2018; and Rappold, et al., 2011). wildfire events to health outcomes • A recent study has linked wildfire smoke to an increase in out-of-hospital cardiac arrests (Jones, et al., 2020) experienced thereafter. The • Other studies have failed to find associations between smoke and cardiovascular-related effects of repeated or prolonged emergency department visits (Alman, et al., 2016), physician visits, and hospital admissions (Henderson, et al., 2011). exposure to wildfire smoke still are not widely understood. (As we Poor Pregnancy and Birth Outcomes discuss in the box on the next • A couple of recent papers have found associations between smoke and pre-term births (Heft-Neal, et al., 2022 and Abdo, et al., 2019). page, relatively little research on • Recent studies have also found links between smoke and a greater risk of gestational the health effects of prescribed diabetes in pregnant people (Abdo, et al., 2019), as well as slightly reduced birth weight among infants exposed to smoke in utero (Holstius, et al., 2012). fire has been conducted, but existing research suggests it likely Increased Mortality has substantially fewer negative • Various studies have found a positive relationship between smoke and-all-cause and impacts than wildfires.) respiratory-related mortality (Chen, et al., 2021 and Doubleday et al., 2020). • Research is more mixed regarding the relationship between smoke and cardiovascular-related mortality, with some research finding positive associations (Chen, et al., 2021) and others not (Doubleday et al., 2020). www.lao.ca.gov 9 AN LAO REPORT Health Impacts From Prescribed Fires Available Evidence Suggests Prescribed Fires Likely Have Fewer Impacts. The health effects of prescribed fires are not fully understood, since associated research is limited. However, available evidence suggests that smoke from prescribed fires likely has substantially fewer negative effects than from wildfires. For example, a 2019 study comparing children in Fresno who were exposed to similar-sized fires found that those exposed to prescribed burns showed lower levels of pollutants in their blood (such as fine particulate matter of2.5 microns in diameter or less, known as PM ) compared to those exposed to wildfires. Additionally, in 2021, the United 2.5 States Environmental Protection Agency published a report analyzing case studies of two wildfires, which concluded that scenarios in which prescribed fire was used would have resulted in significantly lower emissions of PM . 2.5 A main reason why prescribed fires are considered to be less impactful is that they are planned and managed to specifically avoid major negative effects. For example, prescribed fires are typically limited in size and intensity. Additionally, they generally are conducted when atmospheric and weather conditions are favorable, such as when winds are expected to move smoke away from population centers. Finally, because prescribed fires are planned, nearby communities can be notified in advance of prescribed fires, which makes it easier for their impacts to be mitigated. Nevertheless, continuing to research the effects of prescribed fires will be important to better understand how to most effectively mitigate their effects. As we discuss in the next section of this report, the California Air Resources Board has been supporting some such research. brain-training game were not randomly selected sensitivity, and lower adaptive capacity can cause and their exposure to smoke was not measured varying levels of vulnerability to wildfire smoke. with precision. Nonetheless, when taken together, • Health Status. Some health conditions these studies suggest that exposure to smoke has make people more sensitive to the effects of important effects beyond those that are captured wildfire smoke. For example, conditions such in readily observable health measures such as as asthma or chronic obstructive pulmonary emergency room admissions. disease can be exacerbated by wildfires. Pregnancy can make people more sensitive Certain Groups are More Vulnerable to to the effects of wildfire smoke by increasing Negative Effects of Wildfire Smoke breathing rates and blood volumes. Also, Exposure, Sensitivity, and Adaptive Capacity wildfire smoke can affect fetuses. For example, Affect Vulnerability to Wildfire Smoke. Three as mentioned above, some research links key factors make some individuals and households exposure to wildfire smoke with elevated risks more vulnerable to smoke than others. First, some of preterm birth. populations are more likely to be exposed to smoke • Age. Babies and children are considered to due to their occupation and other characteristics. be more vulnerable to wildfire smoke. This is Second, some individuals might be comparatively primarily because (1) their lungs and immune more susceptible to being harmed when they are systems are still developing, which makes exposed to a given amount of smoke (often referred them more sensitive to smoke; (2) they inhale to as sensitivity). Third, individuals and households more air per pound than adults, so they get a can be more vulnerable if they do not have the greater dose of pollutants; and (3) children tend capacity or resources to adapt to smoke exposure to spend more time outside, which increases (often referred to as adaptive capacity). As we show their potential exposure. Older adults, generally in Figure 6 and discuss below, characteristics those over 65, also are considered to be more associated with increased exposure, higher 10 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT vulnerable, in part because they have higher Figure 6 rates of underlying health issues—such as conditions affecting the lungs and heart—and People With Greater Vulnerability to the because people typically experience a gradual Effects of Wildfire Smoke decline in physiological processes as they age. • Occupation. Certain occupations are Health Status associated with greater levels of smoke exposure. Most notably, compared to the general population, firefighters are typically exposed to wildfires at closer proximities and more frequently. Thus, while firefighters Pregnant People Those With Heart and generally are a relatively healthy population, Lung Conditions some evidence suggests that they may face some elevated effects from smoke exposure, Age such as declining lung function. Other outdoor workers, such as those in the agricultural and construction sectors, also experience greater exposure to wildfire smoke, raising their vulnerability. Babies and Young Children Elderly • Socioeconomic Status. Lower-income households also are more vulnerable to wildfire smoke for a few reasons. First, populations Occupation earning lower incomes are more likely to lack housing or live in structures that are not as protective against smoke, such as older housing that is draftier. This can result in more exposure to wildfire smoke. Second, Firefighters Outdoor Workers in general, lower-income households also have fewer resources to adapt, such as by implementing the mitigation measures we Socio-Economic Status discuss further below (like running an air conditioner with a high-efficiency filter). Additionally, populations earning lower incomes also are more likely to have some of the other characteristics described above, such as older People Who Are Unhoused Low-Income Earners age and outdoor jobs, which can contribute to greater vulnerability. • Location. Some individuals and households Location are more vulnerable to smoke as a result of the community in which they live or work. Some conditions that can increase exposure of certain locations to wildfire smoke are their proximity to fire-prone wildlands and their topography. For example, wildfire smoke can get trapped People Who Live Close to Wildlands People Who Live In Areas with in valleys, sometimes exposing residents to Higher Baseline Pollution pollutants for extended periods. Additionally, certain communities—such as those in the San Joaquin Valley air basin—are burdened by higher www.lao.ca.gov 11 AN LAO REPORT levels of baseline pollution from other sources, of Californians earning lower incomes which such as agricultural production and other large therefore may have fewer resources to devote to industries. When wildfire smoke affects people mitigating smoke impacts at the community level. in these communities, it adds an additional load For example, certain communities may have less of particulate matter on top of that significant ability to support extended hours at libraries and existing level. Additionally, some communities community centers to serve as locations where are home to disproportionately large populations residents can go to avoid smoke. RESPONDING TO THE IMPACTS OF WILDLAND FIRE SMOKE While wildland fire smoke can have negative • Improving Window and Door Sealing. effects, particularly on certain populations, various Improved sealing of buildings—such as by approaches can help mitigate these effects. In this replacing old, leaky, single-paned windows section, we summarize these approaches. We also with well-sealed double-paned versions—can discuss some activities government agencies currently reduce the infiltration of smoke and other are undertaking to address the issue of smoke from outdoor pollution. Pairing improved sealing wildland fires in California. with filtering of indoor air is important, as Approaches to Reduce Effects of Wildland Fire Smoke Figure 7 Generally, efforts to mitigate the effects of Examples of Approaches to wildland fire smoke focus on actions to reduce the Reducing Impacts of Wildfire Smoke concentration of exposure to pollutants, the duration of exposure to pollutants, and the rate of inhalation of the pollutants in smoke. We summarize these approaches Replace HVAC below, some of which are shown in Figure 7. filter with MERV 13 or higher and Decreasing Proximity to Smoke. One approach run continuously. to reducing smoke exposure is to leave the affected area and travel to an area with lower concentrations Keep doors and windows shut. of pollutants. Improve seals on doors and windows. Creating Clean Air Spaces. Another way to reduce smoke exposure is to make indoor spaces—such as individual homes, workplaces, schools, or community centers—cleaner. This can be accomplished by taking a variety of actions aimed at reducing the amount of smoke that travels into buildings and filtering the indoor air. Such actions include: Wear well-fitted masks when outdoors. • Closing Windows and Doors. If windows are open, the level of particulate matter indoors Avoid strenuous activities. is likely to be similar to outdoors. If windows are closed, pollutant levels can be maintained at lower levels, particularly if the indoor air HVAC = heating, ventilation, and air conditioning and is filtered. After a wildland fire event, it is MERV = Minimum Efficiency Reporting Value. important to open windows and doors again, so any pollutants that may have accumulated inside can be released. 12 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT discussed below. Otherwise, indoor air quality in each breath. Notably, over a longer period, can gradually decline, since some smoke reduced activity levels can lead to other negative from the outdoors still is likely to enter even effects, so this approach may have some trade-offs. well-sealed buildings over time. Also, absent Using Respiratory Protective Equipment filtration, a well-sealed building can be prone When Outdoors. Particularly when outside, to accumulating higher concentrations of wearing a respirator or a high-quality mask, such indoor pollutants (such as from gas stoves), as an N95 mask or equivalent, can help reduce which can also have some offsetting negative smoke effects. N95 masks are certified to filter health effects. out at least 95 percent of airborne particulates of • Using High-Efficiency Filters. One way to at least 0.3 microns in size, and studies show that maintain cleaner indoor air is to place air filters they can filter pollutants from smoke. However, with a Minimum Efficiency Reporting Value the real-world effectiveness of these masks varies (MERV) rating of at least 13 in a building’s greatly depending on their quality and fit. heating, ventilation, and air conditioning Barriers Exist for Implementing Smoke (HVAC) system. (Air filters are assigned a Mitigations. The approaches discussed above MERV rating from 1-16. Typically, the higher rely on people taking individual steps to protect the number, the higher the filter’s efficiency at themselves from smoke, but such actions may not removing pollutants, such as PM .) Recent always be possible. In practice, individuals may 2.5 research has found that HVAC systems with not always know when smoke levels are elevated high-efficiency filters can be effective at or what steps they should take. Additionally, even improving indoor air quality, but the level of if they do have this information, it is not always effectiveness varies. For example, a 2020 feasible for people, particularly those with limited study found that MERV 14E filters were about resources, to undertake the approaches discussed 40 percent effective on average at reducing above. For example, some people have job PM , with a range of between 15 percent and responsibilities that make leaving areas affected by 2.5 90 percent depending on the characteristics smoke or remaining indoors impossible. Those who of the homes and HVAC systems. can remain indoors still may face barriers to • Operating Portable Air Purifiers. Another keeping their indoor air clean. For example, people effective way to filter indoor air is to use a do not always have control over the quality of the air portable, stand-alone air purifier. A 2021 in the indoor spaces they occupy for large portions literature review by the United States of the day, such as their workplaces or schools. Environmental Protection Agency concluded Also, the cost of electricity and high-efficiency that portable air purifiers reduce indoor PM filters for HVAC systems can be cost-prohibitive 2.5 concentrations by 40 percent to 90 percent, for low-income households. Additionally, some depending on the characteristics of the homes lack HVAC systems, and low-income buildings and the study design. Notably, households may find purchasing and operating a 2017 study modeled various options portable air purifiers unaffordable. Also, for those for improving air filtration in homes during without HVAC systems, indoor temperatures can Southern California wildfire events and sometimes become intolerably warm if windows found that the long-term benefits of these air are shut. An additional complication is that wildfires purifiers (as measured by the value of reduced can be accompanied by power shutoffs, which mortality) generally outweigh the costs. prevent the use of HVAC and portable air purifier systems. In concept, providing clean indoor spaces Reducing Outdoor Exposure and Activity in community centers—which can be outfitted Level. One approach to reducing wildfire smoke with high-quality air filters and powered by backup exposure is to go inside where air can be filtered. power sources—can help households that are not When remaining outside, exposure can be able to maintain good air quality in their homes. reduced by evading strenuous activities to avoid However, for these centers to be effective, making taking in higher volumes of air—and pollutants— www.lao.ca.gov 13 AN LAO REPORT them sufficiently accessible and comfortable for State Agencies Are Undertaking Steps people to stay long enough to effectively reduce to Address Wildland Fire Smoke. State their smoke exposure is essential. As noted in agencies currently are undertaking a number a 2020 report by the National Academies of of smoke-related actions, consistent with their Sciences, Engineering, and Medicine, evidence respective roles and responsibilities. For example, is still lacking on how effective these centers based on information provided by CARB and of Sciences, Engineering, and Medicine are at CDPH, we estimate that these two departments improving respiratory health in practice. are spending roughly $20 million annually on these and other efforts to related to wildfire fire smoke. Existing Government Activities to Some of the recent or expanded efforts that state Address Effects of Wildfire Smoke agencies are undertaking include: Many Entities Have Roles and • Disseminating Information. Recently, state Responsibilities for Addressing Wildland Fire agencies have been taking additional steps Smoke. As shown in Figure 8, several agencies at to share information about wildfire smoke. various levels of government have responsibilities For example, in 2021, CARB launched a related to wildland fire smoke, including those mobile application known as California related to providing people with information Smoke Spotter, which allows the public to and overcoming other barriers to implementing track prescribed fires and wildfires, access the mitigation measures discussed above. For information on air quality from air quality example, at the local level, air quality management monitors and smoke forecasts, and set up districts (AQMDs) play a key role in collecting and alerts. Also, CDPH, along with CARB, updated tracking local air quality data and issuing air quality a document in 2022 that is intended to serve advisories to help inform the public regarding as a guide for local public health officials. This smoke events. AQMDs also run some programs document summarizes information on sources to help people take individual actions to mitigate of air quality information, populations at smoke impacts. For example, the Bay Area AQMD elevated risks from the effects of smoke, and launched a home air filtration program in 2021. strategies to reduce exposure. It also identifies This program provides portable air purifiers to some considerations for planning public health low-income individuals with poorly controlled responses to smoke events. asthma. Additionally, AQMDs perform regional • Supporting Research to Fill Knowledge air quality planning activities and have certain Gaps. State agencies are funding new air quality permitting responsibilities, such as for research to fill some of the gaps in the existing prescribed burns. understanding of wildland fire smoke. For At the state level, two of the key entities involved example, CARB is funding studies to better in addressing wildland fire smoke include the understand topics such as (1) the impacts California Air Resources Board (CARB) and the of short-term exposure to particulate matter California Department of Public Health (CDPH). on lost work days; (2) the components of These departments have a variety of smoke-related the smoke released when structures burn; roles in addition to their many other responsibilities. and (3) the impacts of short-term, repeated For example, CARB is responsible for coordinating, exposure to wildfire smoke. Results from encouraging, and reviewing the efforts of all levels these studies are expected over the next of government as they affect air quality. CARB also few years. Additionally, CARB funded some plays an important role in monitoring air quality, research on prescribed fires in 2019-20 and including during smoke events, by operating a has identified additional research on this network of permanent and portable air quality topic as a continuing priority in its 2021-24 monitors in collaboration with local and federal research plan. partners. Additionally, CARB provides the public with information on smoke events and funds smoke-related research, among other activities. 14 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT Figure 8 Key Local, State, and Federal Agencies With Roles Related to Wildland Fire Smoke Agency Key Roles and Responsibilities Local Air quality management districts (AQMDs) • Collect and track local air quality data. • Issue public air quality advisories. • Run programs to help mitigate smoke impacts. • Conduct regional air quality planning activities. • Issue prescribed burn permits. Local cities and counties, including health • Issue public health advisories, including those related to wildfire smoke. departments • Operate community centers and other facilities where people can avoid smoke. School districts • Decide whether to cancel events or close schools in response to smoke events. State California Air Resources Board • Coordinates, encourages, and reviews the efforts of all levels of government as they affect air quality. • Operates air quality monitors in collaboration with local and state partners. • Provides public information, such as through the Smoke Spotter mobile application. • Funds research on wildfire smoke. • Provides grants to local AQMDs for Wildfire Smoke Clean Air Center program. • Regulates portable air purifiers. California Department of Public Health • Assesses public health effects of wildfire smoke and recommends protective measures. • Prepares guidance materials and disseminates information to the public. • Funds research on wildfire smoke. California Department of Industrial Relations’ • Issues regulations related to protecting employees from wildfire smoke. Division of Occupational Safety and Health California Office of Health Hazard Assessment • Provides technical assistance assessing health risks. California Department of Forestry and Fire • Suppresses and prevents wildfires on over 31 million acres of mostly Protection privately owned land known as the State Responsibility Area (SRA). • Administers programs, such as the Forest Health grant program, that fund prescribed fire and other forest health activities. • Issues prescribed burn permits in the SRA. Federal U.S. Environmental Protection Agency (U.S. EPA) • Conducts Clean Air Act regulatory processes. Various agencies participating in the Interagency • Monitors and forecasts wildfire smoke levels. Wildland Fire Air Quality Response Program • Maintains AirNow website showing smoke and air quality information, in collaboration with U.S. EPA and other partners. U.S. Forest Service • Owns and manages about 15.5 million acres of federally owned forestland in California. • Developing Guidelines. CDPH is in the • Launching Clean Air Center Pilot Program. process of implementing Chapter 412 of As required by Chapter 393 of 2019 (AB 836, 2021 (AB 619, Calderon), which requires Wicks), CARB is undertaking a $5 million pilot the department to develop a plan with program to establish a network of wildfire recommendations and guidelines for counties smoke clean air centers focused on vulnerable to use in case of a significant air quality event communities, in partnership with three local caused by wildfires or other causes. AQMDs. As of the preparation of this report, the AQMDs were in the process of awarding www.lao.ca.gov 15 AN LAO REPORT grants to specific projects. Notably, the state serve as centralized locations where people also provided a total of $185 million to the can go to avoid smoke events, as well as Strategic Growth Council (SGC) in the 2021-22 other types of events such as heat waves. and 2022-23 budgets to establish community Along with this funding, the Legislature resilience centers, with another $85 million required SGC to provide annual reports planned for 2023-24. These centers, though identifying measurable outcomes achieved by not specifically focused on smoke, may help the centers. FORMULATING THE STATE’S FUTURE RESPONSE TO SMOKE Given the significant health and other impacts Criteria the State Should Consider from smoke—particularly for those who are When Choosing Among Options vulnerable due to their age, health status, or While the state could consider taking various socioeconomic factors—the Legislature may actions to address the issue of smoke from wildland want to consider what additional steps, if any, fires, not all of them may be feasible. In part, this it would like to take beyond those it is already is because the state does not have sole control supporting. In this section, we provide some over the issue. Rather, as mentioned previously, initial guidance to the Legislature as it formulates various non-state entities have important roles its approach to addressing smoke from wildland and responsibilities related to wildland fire smoke. fires in the coming years. We begin by identifying Also, the state has limited funding and resources some types of additional actions that the state and faces a range of other important challenges and other governmental agencies could take to to confront beyond just addressing smoke. address smoke. Next, we identify some criteria the Thus, targeting its funding and policy efforts will Legislature could consider as it prioritizes across be critical for the state, so its limited resources options for addressing wildland fire smoke. can effectively achieve the greatest benefits. As it Types of Actions State does so, we suggest that the Legislature focus on supporting the activities that meet certain criteria Could Consider Taking discussed below. State Has Various Options for Expanding Activities That Lend Themselves to State Efforts. As shown in Figure 9, government Role. Some types of activities make sense for entities, including the state, could consider taking the state to undertake, rather than relying on several types of activities to build off of existing individuals or local communities or local agencies. efforts to help address the issue of wildland fire These include activities that are accomplished smoke. For example, given that multiple agencies much more efficiently at a large scale (such as currently are involved, the state could undertake the development of educational materials and additional actions to facilitate greater coordination public information systems) and those that require of California’s response to wildland fire smoke. It statewide coordination (such as conducting could also undertake additional strategic planning statewide planning). Similarly, the state is activities, continue to work towards filling gaps well-positioned to support research and pilot in existing research, or provide more targeted projects that provide broad benefits by filling key assistance to vulnerable individuals to undertake gaps in knowledge. Finally, the state could take mitigation measures (such as supporting a home air steps to mitigate the impacts of the smoke from filtration program similar to that operated by the Bay prescribed fires it undertakes, such as by providing Area AQMD). N95 masks. This is because, while prescribed 16 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT Figure 9 Potential Activities for Addressing Wildfire Smoke Activity Description Coordination and planning Undertaking planning activities and coordinating the efforts of the various entities with a range of roles and responsibilities. Research and pilots Supporting and conducting additional research and pilot projects to continue to improve understanding of the best and most cost-effective ways to address wildfire smoke. Facilitating the collection of additional information, such as by making it easier to identify smoke-related health effects in medical data. Air quality monitoring Maintaining and expanding networks of air quality monitoring equipment to improve the quality of information on smoke exposure. Guidance Providing greater guidance to local agencies and the public, such as what conditions should lead to cancellation of outdoor activities. Regulatory requirements Establishing additional regulatory requirements to help mitigate the impacts of smoke, such as activities employers should undertake to protect employees. Education, information, and Providing more information to the public, such as regarding smoke levels and forecasted air outreach quality. Targeted individual and community Funding additional in-kind or financial assistance to offset the costs of undertaking assistance mitigations, such as purchasing portable air purifiers. Prescribed fire and other forest Supporting and conducting more prescribed fires to reduce the risk of high-severity wildfires, management activities which tend to generate more harmful smoke. fires likely are significantly less harmful than the Cost-Effective Activities. To the extent large, severe wildfires that they help prevent, they possible, focusing on supporting areas where still can create localized smoke impacts on nearby good evidence of cost-effectiveness exists is communities. If the state mitigates these impacts, important. By funding activities that are the most it could make prescribed fires more acceptable cost-effective, particularly compared to other to some communities, and thus help support the alternatives, the state can achieve the greatest state’s strategy to increase the use of beneficial fire benefits from a given level of expenditure. When on landscapes. considering cost-effectiveness, the state will want Activities That Fill Demonstrated Need. to ensure that analyses reflect measured efficacy The state and other governmental agencies in real-world settings (rather than, for example, already are undertaking some efforts to address a laboratory setting). This is because certain wildland fire smoke, as discussed above. As such, approaches, such as providing portable air purifiers ensuring that new or expanded activities focus and masks, rely heavily on individuals taking on documented gaps in these activities will be personal actions. Accordingly, given the various important to avoid duplication and address unmet barriers that individuals may face to implementing needs. (In some cases, gaps could occur because them, the effectiveness of these approaches can activities are not being funded currently, while in depend heavily on whether and how they are others current funding might be insufficient due to used in practice. Notably, in some cases, while rising costs, such as from inflation.) For example, approaches may seem promising, evidence on state, local, and federal agencies currently support cost-effectiveness may be lacking. In these cases, various education and outreach activities related the state can play an important role in improving to wildland fire smoke. When deciding whether understanding by funding pilot projects that are to expand these activities, the state will want designed to allow for robust program evaluation to consider whether the current activities have prior to implementing the project statewide. significant deficiencies and, if so, how the proposed Activities Targeting Vulnerable Populations. expansion would address them. As it considers the potential merits of specific activities to reduce the impacts of smoke, the www.lao.ca.gov 17 AN LAO REPORT Legislature also will want to target resources to Activities With Co-Benefits. The Legislature individuals and communities who most need the may seek to not only consider the direct benefits of assistance. As discussed above, some individuals interventions, but also the potential co-benefits. For are more vulnerable due to their health status, instance, some of the activities that mitigate smoke socioeconomic status, or other factors. In such impacts—such as improving access to portable cases, a strong argument exists for the state to air purifiers that improve indoor air quality—have provide in-kind or financial assistance to those who been found to have other benefits, such as reducing could not otherwise afford to undertake mitigation exposure to and transmission of COVID-19 and efforts. Additionally, given the disparities among other airborne viruses. Additionally, undertaking communities, the Legislature could focus efforts projects to improve forest health, such as through on specific areas that are more vulnerable, such as the introduction of prescribed fire, can have those with higher baseline pollution levels, those ecological and public safety benefits in addition to located in greater proximity to fire-prone wildlands, reducing the likelihood of large, intense wildfires or those that have fewer community resources to that create the largest smoke impacts. support local mitigation efforts. CONCLUSION Expecting that the state will eliminate all smoke vulnerable due to their age, health status, or from wildland fires is not realistic. In part, this socioeconomic factors—the Legislature may want is because fire is a natural part of California’s to consider what additional steps, if any, it would landscape. As the state has learned, policies that like to take to mitigate its negative effects. As we attempt to exclude fire can contribute to poor forest discuss, some key criteria for the Legislature to health and ultimately lead to more severe wildfires consider as it chooses among its options include: than would otherwise be the case. Thus, smoke (1) whether the state is the appropriate entity is likely to be an inevitable part of life for many to undertake the activity, (2) whether there is a Californians in the coming years, as wildland fires— demonstrated need for the activity, (3) the strength both intentional prescribed fires and unintentional of the evidence of the activity’s cost-effectiveness, wildfires—cover more of the state’s landscapes. (4) the extent to which activity targets vulnerable Given the significant health and other impacts groups, and (5) the co-benefits the activity provides from this smoke—particularly on those who are beyond reducing the impacts of smoke. 18 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT APPENDIX: SELECTED REFERENCES Abdo, Mona, et al. “Impact of wildfire smoke “California wildfire and forest resilience task on adverse pregnancy outcomes in Colorado, force.” California’s Strategic Plan for Expanding the 2007-2015.” International Journal of Environmental Use of Beneficial Fire (2022). Research and Public Health 16.19 (2019): 3720. Chen, Gongbo, et al. “Mortality risk attributable Adetona, Olorunfemi, et al. “Review of to wildfire-related PM pollution: a global time 2.5 the health effects of wildland fire smoke on series study in 749 locations.” The Lancet Planetary wildland firefighters and the public.” Inhalation Health 5.9 (2021): e579-e587. Toxicology 28.3 (2016): 95-139. Childs, Marissa L., et al. “Daily Local-Level Aguilar-Gomez, Sandra, et al. “This is air: the Estimates of Ambient Wildfire Smoke PM for 2.5 non-health effects of air pollution.” National Bureau the Contiguous US.” Environmental Science & of Economic Research (2022). Technology (2022). Alavy, Masih, and Jeffrey A. Siegel. “In-situ Cleland, Stephanie E., et al. “Short-term effectiveness of residential HVAC filters.” Indoor exposure to wildfire smoke and PM and cognitive 2.5 Air 30.1 (2020): 156-166. performance in a brain-training game: a longitudinal Allen, Ryan W., and Prabjit Barn. “Individual-and study of US adults.” Environmental Health household-level interventions to reduce air Perspectives 130.6 (2022): 067005. pollution exposures and health risks: a review of Doubleday, Annie, et al. “Mortality associated the recent literature.” Current Environmental Health with wildfire smoke exposure in Washington state, Reports 7.4 (2020): 424-440. 2006-2017: a case-crossover study.” Environmental Alman, Breanna L., et al. “The association of Health 19.1 (2020): 1-10. wildfire smoke with respiratory and cardiovascular Eisenman, David P., et al. “Review of the mental emergency department visits in Colorado in 2012: health effects of wildfire smoke, solastalgia, and a case crossover study.” Environmental Health 15.1 non-traditional firefighters.” UCLA Center for (2016): 1-9. Healthy Climate Solutions, David Geffen School of Barn, Prabjit, et al. “Infiltration of forest fire and Medicine at UCLA, & Climate Resolve. Los Angeles, residential wood smoke: an evaluation of air cleaner CA (2021). effectiveness.” Journal of Exposure Science & Fisk, W. J., and W. R. Chan. “Health benefits and Environmental Epidemiology 18.5 (2008): 503-511. costs of filtration interventions that reduce indoor Borgschulte, Mark, David Molitor, and Eric exposure to PM during wildfires.” Indoor Air 27.1 2.5 Zou. “Air pollution and the labor market: Evidence (2017): 191-204. from wildfire smoke.” No. w29952. National Bureau Gan, Ryan W., et al. “The association between of Economic Research (2022). wildfire smoke exposure and asthma-specific Burke, Marshall, et al. “The changing medical care utilization in Oregon during the 2013 risk and burden of wildfire in the United wildfire season.” Journal of Exposure Science & States.” Proceedings of the National Academy of Environmental Epidemiology 30.4 (2020): 618-628. Sciences 118.2 (2021): e2011048118. Heft-Neal, Sam, et al. “Associations between Burke, Marshall, et al. “Exposures and wildfire smoke exposure during pregnancy and behavioural responses to wildfire smoke.” Nature risk of preterm birth in California.” Environmental Human Behaviour (2022): 1-11. Research 203 (2022): 111872. California Department of Public Health. Henderson, David E., Jana B. Milford, and “Wildfire smoke: considerations for public health Shelly L. Miller. “Prescribed burns and wildfires in officials” (2022). Colorado: impacts of mitigation measures on indoor air particulate matter.” Journal of the Air & Waste Management Association 55.10 (2005): 1516-1526. www.lao.ca.gov 19 AN LAO REPORT Henderson, Sarah B., et al. “Three measures Prunicki, Mary, et al. “The impact of of forest fire smoke exposure and their prescribed fire versus wildfire on the immune and associations with respiratory and cardiovascular cardiovascular systems of children.” Allergy 74.10 health outcomes in a population-based (2019): 1989. cohort.” Environmental Health Perspectives 119.9 Rappold, Ana G., et al. “Peat bog wildfire (2011): 1266-1271. smoke exposure in rural North Carolina is Hill, L. L., et al. “The public health dimensions of associated with cardiopulmonary emergency California wildfire and wildfire prevention, mitigation, department visits assessed through and suppression.” (2021). syndromic surveillance.” Environmental Health Hill, L. L., et al. “Can prescribed fires mitigate Perspectives 119.10 (2011): 1415-1420. health harm? A review of air quality and public Reid, Colleen E., et al. “Critical review of health health.” (2022). impacts of wildfire smoke exposure.” Environmental Holstius, David M., et al. “Birth weight following Health Perspectives 124.9 (2016): 1334-1343. pregnancy during the 2003 Southern California Romero, Farida Jhabvala, et al. “Dangerous wildfires.” Environmental Health Perspectives 120.9 air: as California burns, America breathes toxic (2012): 1340-1345. smoke.” KQED, 28 September 2021, https://www. Hurteau, Matthew D., et al. “Projected effects kqed.org/news/11890211/dangerous-air-as-californ of climate and development on California wildfire ia-burns-america-breathes-toxic-smoke. emissions through 2100.” Environmental Science & Stephens, Scott L., Robert E. Martin, and Technology 48.4 (2014): 2298-2304. Nicholas E. Clinton. “Prehistoric fire area and Jones, Caitlin G., et al. “Out-of-hospital cardiac emissions from California’s forests, woodlands, arrests and wildfire-related particulate matter shrublands, and grasslands.” Forest Ecology and during 2015-2017 California wildfires.” Journal Management 251.3 (2007): 205-216. of the American Heart Association 9.8 (2020): U.S. Environmental Protection Agency. “Wildfire e014125. smoke: a guide for public health officials.” (2019). Liu, Jia Coco, et al. “Particulate air pollution U.S. Environmental Protection Agency, Office from wildfires in the Western US under climate of Research and Development. “Comparative change.” Climatic Change 138.3 (2016): 655-666. assessment of prescribed versus wildfire western Malig, Brian J., et al. “Examining fine particulate United States.” (2021). matter and cause-specific morbidity during the Wen, Jeff, and Marshall Burke. “Lower test 2017 North San Francisco Bay wildfires.” Science of scores from wildfire smoke exposure.” Nature the Total Environment 787 (2021): 147507. Sustainability (2022): 1-9. McClure, Crystal D., and Daniel A. Jaffe. “US Wettstein, Zachary S., et al. “Cardiovascular particulate matter air quality improves except in and cerebrovascular emergency department wildfire-prone areas.” Proceedings of the National visits associated with wildfire smoke exposure in Academy of Sciences 115.31 (2018): 7901-7906. California in 2015.” Journal of the American Heart National Academies of Sciences, Engineering, Association 7.8 (2018): e007492. and Medicine. “Implications of the California Zu, Ke, et al. “Long-range fine particulate wildfires for health, communities, and matter from the 2002 Quebec forest fires and daily preparedness: proceedings of a workshop.” mortality in Greater Boston and New York City.” Air National Academies Press, 2020. Quality, Atmosphere & Health 9.3 (2016): 213-221. Pistochini, Theresa, et al. “Improving ventilation and indoor environmental quality in California K-12 schools.” Prepared for the California Energy Commission, 2020. 20 LEGISLATIVE ANALYST’S OFFICE AN LAO REPORT www.lao.ca.gov 21 AN LAO REPORT LAO PUBLICATIONS This report was prepared by Helen Kerstein, and reviewed by Rachel Ehlers and Anthony Simbol. The Legislative Analyst’s Office (LAO) is a nonpartisan office that provides fiscal and policy information and advice to the Legislature. To request publications call (916) 445-4656. This report and others, as well as an e-mail subscription service, are available on the LAO’s website at www.lao.ca.gov. The LAO is located at 925 L Street, Suite 1000, Sacramento, California 95814. 22 LEGISLATIVE ANALYST’S OFFICE