Research Database
Displaying 41 - 60 of 117
Long-term mortality burden trends attributed to black carbon and PM2·5 from wildfire emissions across the continental USA from 2000 to 2020: a deep learning modelling study
Year: 2023
Background
Long-term improvements in air quality and public health in the continental USA were disrupted over the past decade by increased fire emissions that potentially offset the decrease in anthropogenic emissions. This study aims to estimate trends in black carbon and PM2·5 concentrations and their attributable mortality burden across the USA.
Methods
In this study, we derived daily concentrations of PM2·5 and its highly toxic black carbon component at a 1-km resolution in the USA from 2000 to 2020 via deep learning that integrated big data from satellites, models, and surface…
Publication Type: Journal Article
Harnessing Natural Disturbances: A Nature-Based Solution for Restoring and Adapting Dry Forests in the Western USA to Climate Change
Year: 2023
Natural disturbances (wildfires, droughts, beetle outbreaks) shaped temperate forests for millennia, including dry forests of the western USA. Could they now best restore and adapt dry forests to climate change while protecting nearby communities? Mechanical fuel-reduction treatments (e.g., thinning) reduce landscape heterogeneity and appear ineffective since <1% of the treated area encounters fire each year and fires are still increasing. We propose and analyze a nature-based solution (NbS), using natural disturbances, to see whether it is feasible, how long it might take, and whether it…
Publication Type: Journal Article
Evaluating the potential role of federal air quality standards in constraining applications of prescribed fire in the western United States
Year: 2023
Prescribed fire is a useful tool for building resilient landscapes in fire-prone areas across the globe. In the western U.S., prescribed fire is employed by federal, state, and Tribal land managers and planned during particular meteorological and air quality conditions to manage air quality impacts. As agencies prepare to plan and permit more prescribed fire, an ongoing question will be whether existing air quality conditions constrain the potential for more prescribed fire. We performed a set of spatial and statistical analyses to evaluate how prescribed burns are potentially constrained by…
Publication Type: Journal Article
Recent Douglas-fir Mortality in the Klamath Mountains Ecoregion of Oregon: Evidence for a Decline Spiral
Year: 2023
Recent increases in Douglas-fir (Psuedotsuga menziesii var. menziesii) mortality in the Klamath Mountains ecoregion raise concerns about the long-term resilience of Douglas-fir in the ecoregion and increased potential for uncharacteristic wildfire. We used data from the USDA Forest Service Aerial Detection Survey and ninety-six field plots to explore the relationships between physiographic and climate variables and Douglas-fir mortality. Our results provide strong evidence for a decline spiral in which Douglas-fir growing on hot, dry sites (predisposing factor) are further stressed by drought…
Publication Type: Journal Article
Metal toxin threat in wildland fires determined by geology and fire severity
Year: 2023
Accentuated by climate change, catastrophic wildfires are a growing, distributed global public health risk from inhalation of smoke and dust. Underrecognized, however, are the health threats arising from fire-altered toxic metals natural to soils and plants. Here, we demonstrate that high temperatures during California wildfires catalyzed widespread transformation of chromium to its carcinogenic form in soil and ash, as hexavalent chromium, particularly in areas with metal-rich geologies (e.g., serpentinite). In wildfire ash, we observed dangerous levels (327-13,100 µg kg−1) of reactive…
Publication Type: Journal Article
Environmental justice analysis of wildfire-related PM2.5 exposure using low-cost sensors in California
Year: 2023
Highlights • Wildfire may exacerbate health disparities & environmental justice concerns. • Low-cost PM2.5 sensors improve wildfire impact assessment. • Increases in PM2.5 correlate with wildfire activity (within 30 km). • Indoor increases in PM2.5 concentrations mimic outdoor PM2.5 increase patterns. The increasing number and severity of wildfires is negatively impacting air quality for millions of California residents each year. Community exposure to PM2.5 in two main population centers (San Francisco Bay area and Los Angeles County area) was assessed using the low-cost PurpleAir sensor…
Publication Type: Journal Article
Hydrological and Meteorological Controls on Large Wildfire Ignition and Burned Area in Northern California during 2017–2020
Year: 2023
This study examined the hydrological/meteorological controls on large wildfires > 10,000 acres (40.5 km2) during 2017–2020 in Northern California at spatial and temporal scales of the target wildfires’ occurrence or growth. This study used the following simple indices for analysis: Moisture Deficit Index (MDI) computed by dividing vapor pressure deficit by soil moisture, MDIWIND computed by multiplying MDI by horizontal wind speed, and MDIGUST computed by multiplying MDI by wind gust speed. The ignition location MDIWIND and MDIGUST showed larger values on the ignition date in fire-years…
Publication Type: Journal Article
Prescribed Burns as a Tool to Mitigate Future Wildfire Smoke Exposure: Lessons for States and Rural Environmental Justice Communities
Year: 2023
Smoke from wildfires presents one of the greatest threats to air quality, public health, and ecosystems in the United States, especially in the West. Here we quantify the efficacy of prescribed burning as an intervention for mitigating smoke exposure downwind of wildfires across the West during the 2018 and 2020 fire seasons. Using the adjoint of the GEOS-Chem chemical transport model, we calculate the sensitivities of population-weighted smoke concentrations in receptor regions, including states and rural environmental justice communities, to fire emissions upwind of the receptors. We find…
Publication Type: Journal Article
Social Vulnerability in USCommunities Affected by WildfireSmoke, 2011 to 2021
Year: 2023
Objectives. To describe demographic and social characteristics of US communities exposed to wildfire smoke.
Methods. Using satellite-collected data on wildfire smoke with the locations of population centers in the coterminous United States, we identified communities potentially exposed to light-, medium-, and heavy-density smoke plumes for each day from 2011 to 2021. We linked days of exposure to smoke in each category of smoke plume density with 2010 US Census data and community characteristics from the Centers for Disease Control and Prevention’s Social Vulnerability Index to describe…
Publication Type: Journal Article
Human and climatic influences on wildfires ignited by recreational activities in national forests in Washington, Oregon, and California
Year: 2023
In Washington, Oregon, and California, ignitions from recreational activities accounted for 12% of human-caused wildfires, and 8% of the area burned, from 1992–2020. Wildfires ignited by recreational activities not only increase fire suppression expenditures but have the potential to limit recreational activities traditionally associated with use of fire, such as camping. From 1992–2020, 50% of recreation-caused ignitions in these three states occurred on lands managed by the U.S. Forest Service. The mean annual number of recreation-caused ignitions on national forests in the three states…
Publication Type: Journal Article
A comparison of smoke modelling tools used to mitigate air quality impacts from prescribed burning
Year: 2023
Background. Prescribed fire is a land management tool used extensively across the United States. Owing to health and safety risks, smoke emitted by burns requires appropriate manage- ment. Smoke modelling tools are often used to mitigate air pollution impacts. However, direct comparisons of tools’ predictions are lacking. Aims. We compared three tools commonly used to plan prescribed burning projects: the Simple Smoke Screening Tool, VSmoke and HYSPLIT. Methods. We used each tool to model smoke dispersion from prescribed burns conducted by the North Carolina Division of Parks and Recreation…
Publication Type: Journal Article
Exposure to wildfires and health outcomes of vulnerable people: Evidence from US data
Year: 2023
This paper investigates the causal effect of wildfire exposure on birth outcomes and older people’s health outcomes in United States (US). The study focuses on three sub-questions for each health outcome: (1) the causal effect of each of the five largest wildfires on individual health, (2) the causal impact of multiple large wildfires on individual health outcomes, and (3) the causal influence of wildfires larger than different sizes within different distances of counties on health outcomes at the county level. The analysis exploits data from National Vital Statistics System, Behavioural Risk…
Publication Type: Journal Article
Social vulnerability of the people exposed to wildfires in U.S. West Coast states
Year: 2023
Understanding of the vulnerability of populations exposed to wildfires is limited. We used an index from the U.S. Centers for Disease Control and Prevention to assess the social vulnerability of populations exposed to wildfire from 2000–2021 in California, Oregon, and Washington, which accounted for 90% of exposures in the western United States. The number of people exposed to fire from 2000–2010 to 2011–2021 increased substantially, with the largest increase, nearly 250%, for people with high social vulnerability. In Oregon and Washington, a higher percentage of exposed people were highly…
Publication Type: Journal Article
Quantifying the contribution of major carbon producers to increases in vapor pressure deficit and burned area in western US and southwestern Canadian forests
Year: 2023
Increases in burned forest area across the western United States and southwestern Canada over the last several decades have been partially driven by a rise in vapor pressure deficit (VPD), a measure of the atmosphere’s drying power that is significantly influenced by human-caused climate change. Previous research has quantified the contribution of carbon emissions traced back to a set of 88 major fossil fuel producers and cement manufacturers to historical global mean temperature rise. In this study, we extend that research into the domain of forest fires. We use a global energy balance…
Publication Type: Journal Article
Quantifying the smoke-related public health trade-offs of forest management
Year: 2023
Prescribed burning can mitigate extreme wildfire risk and reduce total smoke emissions. Yet prescribed burns’ emissions may also contribute to smoke exposures in nearby communities. Incorporating public health considerations into forest management planning efforts may help reduce prescribed burn-related exposure impacts. We present a methodological framework linking landscape ecology, air-quality modelling and health impact assessment to quantify the air-quality and health impacts of specific management strategies. We apply this framework to six forest management scenarios proposed for a…
Publication Type: Journal Article
More smoke today for less smoke tomorrow? We need to better understand the public health benefits and costs of prescribed fire
Year: 2022
Rapidly scaling up the use of prescribed fire is being promoted as an important pathway for reducing the growing damages of wildfire events in the United States, including limiting the health impacts from smoke emissions. However, we do not currently have the science needed to understand how the health impacts associated with prescribed fire smoke in the present compare to wildfire smoke exposure in the future. In particular, we lack an understanding of how the potential long-term public health benefits of prescribed fire on future wildfire smoke and health impacts compare to prescribed fire’…
Publication Type: Journal Article
Rapid Growth of Large Forest Fires Drives the Exponential Response of Annual Forest-Fire Area to Aridity in the Western United States
Year: 2022
Annual forest area burned (AFAB) in the western United States (US) has increased as a positive exponential function of rising aridity in recent decades. This non-linear response has important implications for AFAB in a changing climate, yet the cause of the exponential AFAB-aridity relationship has not been given rigorous attention. We investigated the exponential AFAB-aridity relationship in western US forests using a new 1984–2019 database of fire events and 2001–2020 satellite-based records of daily fire growth. While forest-fire frequency and duration grow linearly with aridity, the…
Publication Type: Journal Article
Future climate risks from stress, insects and fire across US forests
Year: 2022
Forests are currently a substantial carbon sink globally. Many climate change mitigation strategies leverage forest preservation and expansion, but rely on forests storing carbon for decades to centuries. Yet climate-driven disturbances pose critical risks to the long-term stability of forest carbon. We quantify the climate drivers that influence wildfire and climate stress-driven tree mortality, including a separate insect-driven tree mortality, for the contiguous United States for current (1984–2018) and project these future disturbance risks over the 21st century. We find that current…
Publication Type: Journal Article
Oregon Wildfire Smoke Communications and Impacts: An Evaluation of the 2020 Wildfire Season
Year: 2022
Oregon Health Authority and the University of Oregon partnered to conduct a survey-based evaluation of wildfire smoke communications and impacts experienced by Oregon residents during the 2020 wildfire season. The purpose of this survey was to (1) understand how Oregonians respond to wildfire smoke and (2) provide an open-source evaluation tool and data to support wildfire smoke communication practitioners in Oregon.
Publication Type: Journal Article
Increasing co-occurrence of fine particulate matter and ground-level ozone extremes in the western United States
Year: 2022
Wildfires and meteorological conditions influence the co-occurrence of multiple harmful air pollutants including fine particulate matter (PM2.5) and ground-level ozone. We examine the spatiotemporal characteristics of PM2.5/ ozone co-occurrences and associated population exposure in the western United States (US). The frequency, spatial extent, and temporal persistence of extreme PM2.5/ozone co-occurrences have increased significantly between 2001 and 2020, increasing annual population exposure to multiple harmful air pollutants by ~25 million person-days/year. Using a clustering methodology…
Publication Type: Journal Article