AbstractSmoke from wildland fire is a significant concern to resource managers who need tools, knowledge, and training to analyze, address, and minimize potential impacts; follow relevant rules and regulations; and inform the public of possible effects. Successful navigation of competing pressures to appropriately use fire on the landscape to manage fire-adapted and fire-dependent ecosystems, while protecting public health and other air quality values, depends on credible science and tools conceived of and developed in partnership between managers and the research community. Fire and smoke management are made even more complex by the current condition of ecosystems as a result of fire exclusion and the future implications of a changing climate. This chapter describes the scope of smoke management, social and regulatory contexts, and pathways through which scientific information and tools can improve the accuracy and timeliness of management and communication with the public.

AbstractSmoke plume dynamic science focuses on understanding the various smoke processes that control the movement and mixing of smoke. A current challenge facing this research is providing timely and accurate smoke information for the increasing area burned by wildfires in the western USA. This chapter synthesizes smoke plume research from the past decade to evaluate the current state of science and identify future research needs. Major advances have been achieved in measurements and modeling of smoke plume rise, dispersion, transport, and superfog; interactions with fire, atmosphere, and canopy; and applications to smoke management. The biggest remaining gaps are the lack of high-resolution coupled fire, smoke, and atmospheric modeling systems, and simultaneous measurements of these components. The science of smoke plume dynamics is likely to improve through development and implementation of: improved observational capabilities and computational power; new approaches and tools for data integration; varied levels of observations, partnerships, and projects focused on field campaigns and operational management; and new efforts to implement fire and stewardship strategies and transition research on smoke dynamics into operational tools. Recent research on a number of key smoke plume dynamics has improved our understanding of coupled smoke modeling systems, modeling tools that use field campaign data, real-time smoke modeling and prediction, and smoke from duff burning. This new research will lead to better predictions of smoke production and transport, including the influence of a warmer climate on smoke.

Throughout the United States, wildland firefighters respond to wildfires, performing arduous work in remote locations. Wildfire incidents can be an ideal environment for the transmission of infectious diseases, particularly for wildland firefighters who congregate in work and living settings. In this review, we examine how exposure to wildfire smoke can contribute to an increased likelihood of SARS-CoV-2 infection and severity of coronavirus disease (COVID-19). Human exposure to particulate matter (PM), a component of wildfire smoke, has been associated with oxidative stress and inflammatory responses; increasing the likelihood for adverse respiratory symptomology and pathology. In multiple epidemiological studies, wildfire smoke exposure has been associated with acute lower respiratory infections, such as bronchitis and pneumonia. Co-occurrence of SARS-CoV-2 infection and wildfire smoke inhalation may present an increased risk for COVID-19 illness in wildland firefighters due to PM based transport of SARS CoV-2 virus and up-regulation of angiotensin-converting enzyme II (ACE-2) (i.e. ACE-2 functions as a trans-membrane receptor, allowing the SARS-CoV-2 virus to gain entry into the epithelial cell). Wildfire smoke exposure may also increase risk for more severe COVID-19 illness such as cytokine release syndrome, hypotension, and acute respiratory distress syndrome (ARDS). Current infection control measures, including social distancing, wearing cloth masks, frequent cleaning and disinfecting of surfaces, frequent hand washing, and daily screening for COVID-19 symptoms are very important measures to reduce infections and severe health outcomes. Exposure to wildfire smoke may introduce additive or even multiplicative risk for SARS-CoV-2 infection and severity of disease in wildland firefighters. Thus, additional mitigative measures may be needed to prevent the co-occurrence of wildfire smoke exposure and SARS-CoV-2 infection.

Wildland fire emissions from both wildfires and prescribed fires represent a major component of overall U.S. emissions. Obtaining an accurate, time-resolved inventory of these emissions is important for many purposes, including to account for emissions of greenhouse gases and short-lived climate forcers, as well as to model air quality for health, regulatory, and planning purposes. For the U.S. Environmental Protection Agency's 2011 and 2014 National Emissions Inventories, a new methodology was developed to reconcile the wide range of available fire information sources into a single coherent inventory. The Comprehensive Fire Information Reconciled Emissions (CFIRE) inventory effort utilized satellite fire detections as well as a large number of national, state, tribal, and local databases. The methodology and results for CONUS and Alaska were documented and compared against other fire emissions databases, and the efficacy of the overall effort was evaluated. Results show the overall spatial pattern differences and relative seasonality of wildfires and prescribed fires across the country. Prescribed burn emissions occurred primarily in non-summer months were concentrated in the Southeast, Northwest, and lower Midwest, and were relatively consistent year to year. Wildfire emissions were much more variable but occurred primarily in the summer and fall. Overall, CFIRE represents a third of total emitted PM2.5 across all sources in the National Emissions Inventory, with prescribed fires accounting for nearly half of all CFIRE emissions. Compared with other wildland fire emissions inventories derived solely from satellite detections, the CFIRE inventory shows markedly increased emissions, reflecting the importance of the multiple national and regional databases included in CFIRE in capturing small fires and prescribed fires in particular. Implications: Wildland fire emissions inventories need to incorporate multiple sources of fire information in order to better represent the full range of fire activity, including prescribed burns and smaller fires. For the 2011 and 2014 U.S. National Emissions Inventory, a methodology was developed to collect, associate, and reconcile fire information from satellite data as well as a large number of national, regional, state, local, and tribal fire information databases across the country. The resulting emissions inventory shows the importance of this type of integration and reconciliation when compared against other emissions inventories for the same period.

Where there is fire, there is smoke. Air quality impacts from wildfires have become significant health events in the United States and Canada. These incidents are commonly the highest air pollution exposures that face the American The same situation is occurring in Canada. The movement of smoke crossing boundaries is also a common challenge. These impacts are not only high, they are also becoming longer in duration with communities frequently facing multiple weeks of exposure. In 2018, over 3,700 instances of 24 hours above health thresholds for fine particulate occurred in the Western U.S.  These impacts pose a significant cost to society through health effects and disruption of normal activities for both vulnerable and healthy populations. The USDA Forest Service has been leading the development of the Interagency Wildland Fire Air Quality Response Program to address the air quality impacts of wildland fires on the American The Program utilizes emergency deployable air quality monitoring equipment, state of the art wildland fire smoke dispersion models, and development of specialized Air Resource Advisors (ARAs) for dispatch to ongoing wildfires to develop y available and disseminated smoke impact forecasts. In Canada, efforts are underway at federal, provincial and First Nation levels to address smoke impacts. Approaches in both countries mutually support pre-fire preparation for smoke and direct response to incidents. The lessons learned and tools to support wildfire smoke planning and response have broader applicability for Integrated Fire Management. As the learns of the health impacts of wildland fire smoke and how to protect themselves from such air pollution, they are building preparation and readiness for smoke from less smoke-filled prescribed fires. A prepared especially those who are vulnerable and frequently vocally opposed to use of fire due to smoke concerns, will facilitate more use of fire in controlled settings and prescribed fires which will aid overall Integrated Fire Management objectives. Â

Wildland fire emissions degrade air quality and visibility, having adverse economic, health and visibility impacts at large spatial scales globally. Air quality regulations can constrain the goals of landscape resilience and management of fire-dependent ecosystems. Here, we review the air quality regulatory framework in the United States, comparing this framework with that of Australia. In the United States, wildland fire management and air quality policies have evolved independently, yet interact to meet diverse public needs. Australian policy development is more recent and decentralised. We find that (1) for maxiumum effectiveness, smoke and fire regulatory frameworks must keep pace with scientific evidence, environmental and social change, and be accompanied by clear regulatory guidance; (2) episodic, non-stationary qualities of fire, and its role in ecosystems, pose specific challenges to regulators and policy-makers; and (3) the complexity of industry-focused air quality policies often leads to unintended consequences for fire management. More research is needed to create and implement more effective fire and air policies and better prepare social-ecological systems to address the challenges of climate change mitigation. These insights may be helpful for countries initially developing complementary fire and air policies, especially as the role of fire becomes more important geopolitically and globally.

This strategic plan is a technical discussion of the implementation and development of models and data systems used to manage the air quality impacts of wildland and prescribed fires. Strategies and priorities in the plan were generated by the Express Team (chartered by the National Wildfire Coordinating Group) and a diverse group of 86 subject matter experts who attended a national planning workshop. Air pollution from fires used to manage ecosystems is an issue in many parts of the country. Land managers are rapidly expanding the use of fire for managing ecosystems, while air resource managers are accelerating efforts to reduce the impacts of fires on air quality. This plan provides a conceptual design as a first step toward balancing these goals, identifies information needs to support management and policy development, and identifies strategies for developing and implementing models and data systems. The conceptual design was based around a three-dimensional array of air resource components and fire management components at various project scales. This array was reduced to nine program elements, each with a description of their scope, current situation, desired state, and strategies to reach that state. The Express Team recommends nine summary strategies as a synthesis of internal discussions, review comments, and proceedings of the national workshop. The strategies recommended relate to: Fuel and fire characterization Emission modeling systems Transport, dispersion, and secondary pollutant formation Air quality impact assessment Emissions tradeoffs and determination of natural visibility Impact and risk assessment of emissions from fires Monitoring guidelines and protocols National fire and air quality information database Public information and protection.