Researchers compare smoke emissions from prescribed and wild fires

DC-10 drop North Park Fire
A DC-10 comes out of the smoke dropping retardant on the North Park Fire in Southern California, October 12, 2018. Screen grab from @ABC7Leticia video.

Four researchers, in a study funded by the U.S. Forest Service, evaluated data collected in 25 previous studies to compare exposure to particulate matter (PM2.5) created by prescribed fires and wildfires. The authors were Kathleen Navarro, Don Schweizer, John Balmes, and Ricardo Cisneros. Titled, A Review of Community Smoke Exposure from Wildfire Compared to Prescribed Fire in the United States, it is published under Open Access guidelines.

Below are excerpts from the study — the abstract and conclusions. And, information about a March 21 webinar featuring Ms. Navarro about the health effects of vegetation smoke.


Prescribed fire, intentionally ignited low-intensity fires, and managed wildfires-wildfires that are allowed to burn for land management benefit-could be used as a land management tool to create forests that are resilient to wildland fire. This could lead to fewer large catastrophic wildfires in the future. However, we must consider the public health impacts of the smoke that is emitted from wildland and prescribed fire.

The objective of this synthesis is to examine the differences in ambient community-level exposures to particulate matter (PM2.5) from smoke in the United States in relation to two smoke exposure scenarios-wildfire fire and prescribed fire. A systematic search was conducted to identify scientific papers to be included in this review. TheWeb of Science Core Collection and PubMed, for scientific papers, and Google Scholar were used to identify any grey literature or reports to be included in this review. Sixteen studies that examined particulate matter exposure from smoke were identified for this synthesis-nine wildland fire studies and seven prescribed fire studies. PM2.5 concentrations from wildfire smoke were found to be significantly lower than reported PM2.5 concentrations from prescribed fire smoke.

Wildfire studies focused on assessing air quality impacts to communities that were nearby fires and urban centers that were far from wildfires. However, the prescribed fire studies used air monitoring methods that focused on characterizing exposures and emissions directly from, and next to, the burns.

This review highlights a need for a better understanding of wildfire smoke impact over the landscape. It is essential for properly assessing population exposure to smoke from different fire types.


Destructive wildfires have higher rates of biomass consumption and have greater potential to expose more people to smoke than prescribed fires. Naturally ignited fires that are allowed to self-regulate can provide the best scenario for ecosystem health and long-term air quality. Generally, prescribed fire smoke is much more localized, and the smoke plumes tend to stay within the canopy, which absorbs some of the pollutants, reducing smoke exposure. Land managers want to utilize prescribed fire as a land management tool to restore fire-adapted landscapes. Thus, additional work is needed to understand the differences in exposures and public health impacts of smoke of prescribedfire compared to wildfire. One way to do this would be for managers to collaborate with air quality departments (internal to agency or external) to monitor PM2.5concentrations in communities near a prescribed fire.

Consistent monitoring strategies for all wildland fires, whether prescribed or naturally occurring, are needed to allow the most robust comparative analysis. Currently, prescribed fire monitoring is often focused on capturing the area of highest impact or characterizing fire emissions, while wildfire monitoring often relies on urban monitors supplemented by temporary monitoring of communities of concern. A better understanding of smoke impact over the landscape and related impacts is essential for properly assessing population exposure to smoke from different fire types.

(end of excerpt)

In a webinar March 21 at 11 a.m. CDT, Ms. Navarro will describe information from a different smoke study. She will present on a recent Joint Fire Science Program study estimating the lifetime risk of lung cancer and cardiovascular disease from exposure to particulate matter (PM) from smoke. This analysis combined measured PM exposures on wildfires, estimated wildland firefighter breathing rates, and an exposure disease relationship for PM to estimate mortality of lung cancer and cardiovascular disease mortality from lifetime exposure to PM.

Breathing wildfire smoke can be similar to smoking up to two packs of cigarettes a day

Research shows its worse than we thought

bird dog airplane fire smoke wildfire
A Canadian bird dog airplane disappears into smoke over the Highland Fire in South Dakota, July 1, 2012. Photo by Bill Gabbert.

According to a researcher with the University of Alberta, breathing smoke from a wildfire can be equivalent to smoking up to two packs of cigarettes a day, depending on the density.

Accumulating over time, smoke particles trapped in the lungs can cause “all kinds of problems,” Mike Flannigan of the university’s Department of Renewable Resources told the Associated Press. “The more we learn about smoke and health, the more we are finding out it is bad for us, which isn’t a surprise but it’s worse than we thought.”

The AP reported that Mr. Flannagin was scheduled to make a presentation at the British Columbia Lung Association’s annual workshop on air quality and health on February 6, 2019.

FEMA to fund a study of health effects on wildland firefighters

The research will be supported by a $1.5 million award.

University of Maryland (UMD) Associate Professor Michael Gollner will co-lead a first-of-its-kind research effort to quantify the pulmonary and cardiovascular health consequences to firefighters exposed to wildland fire smoke. The research is supported  by a $1.5 million award from the Assistance to Firefighters Grant Program administered through the Federal Emergency Management Agency (FEMA), a Department of Homeland Security agency.

The smoke of wildland fires—such as California’s Mendocino Complex of Fires, which burned 459,123 acres, destroyed 280 structures (including 157 residences), and killed a firefighter during the 2018 wildfire season—contains particulate matter, carbon monoxide, volatile organic carbon compounds, and other toxic hazards that could put firefighters at risk for chronic illnesses such as ischemic heart disease, cardiovascular disease, and chronic obstructive pulmonary disease (such as emphysema and chronic bronchitis).

firefighters smoke cancer cold brook prescribed fire
Members of a hotshot crew work in smoke on the Cold Brook Prescribed Fire, October 23, 2014. Photo by Bill Gabbert.

But unlike structural firefighters who have relatively well-defined respiratory personal protective equipment standards for fighting fires in and near buildings, wildland firefighters have no standards or requirements for prescriptive respiratory protection. And because wildland firefighters are often deployed to a fire for weeks at a time with sometimes repeated deployments for several months over a summer, they experience an exposure pattern with unknown health risks.

“We put wildland firefighters in harm’s way to protect the natural environment, homes and property, and lives. The focus on firefighter safety has largely been about physical injuries such as burns—but as you can imagine, these firefighters are also exposed to a great deal of smoke,” explains Gollner, a fire protection engineer in UMD’s A. James Clark School of Engineering. “We know there can be health consequences to this, but we have no data on the long-term effect of wildland fire emissions on the heart, blood vessels, and lungs of front-line wildfire responders, because it’s incredibly difficult to study.”

The FEMA-funded research will look at different smoke exposures that mimic both smaller prescribed fires (i.e., planned fires that are used to meet management objectives and that consider the safety of the public, weather, and probability of meeting burn objectives) and larger wildfires—as well as the benefit provided by different types of simple respiratory personal protective equipment.

The research team, led by principal investigators and bioengineers Jessica Oakes and Chiara Bellini of Northeastern University, hopes the three-year project will inform which fire scenarios are the most dangerous with greatest risk to firefighters’ pulmonary and cardiovascular health. Perhaps most importantly, it could lead to recommendations for respiratory personal protective equipment that is easily implemented in the field and/or possible changes in tactics to mitigate exposure, with the goal of preserving firefighters’ long-term health.

“Unlike structural firefighters, who will put on an air-purifying respirator or a self-contained breathing apparatus when they enter a building, wildland firefighters typically cover their face with only a simple bandana,” says Gollner. “Bandanas are a common tactic because they don’t add an additional burden of weight to firefighters’ already strenuous activity. However, it is unknown if, or to what extent, this provides health benefits.”

The research team will combine their expertise to solve this challenging problem: Gollner will contribute novel expertise in firefighting practices and fire generation, while Oakes and Bellini will offer interdisciplinary bioengineering expertise that’s critical to understanding this complex health problem. They will also work with the International Association of Fire Fighters and National Fire Protection Association to facilitate input from stakeholder partners including firefighters from several departments across the country, fire organization representatives, health researchers, governmental agencies, and members of technical committees overseeing personal protective equipment standards.

To learn more about Gollner’s research:

National Science Foundation studied 21 wildfire plumes this year

Their instrument-laden C-130 conducted 16 research flights out of Boise

NSF smoke wildfire study 2018
National Science Foundation C-130 used for studying wildfire smoke in 2018. NSF photo.

A C-130 outfitted with research equipment was based at Boise last summer in order to study smoke produced by wildfires. The missions were conducted by the National Center for Atmospheric Research which is a unit within the National Science Foundation. The name of the project is a mouthful: Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption and Nitrogen (WE-CAN) Field Campaign.

The organization provided this overview of the work they did over fires this year:

Western wildfire smoke has a significant impact on air quality, nutrient cycles, weather and climate. The chemistry inside a smoke plume during the first 24 hours after emission affects reactive nitrogen partitioning, cloud chemistry and nucleation, and aerosol scattering and absorption, all of which can impact air quality and climate.

The NSF-funded WE-CAN ground-based and airborne field campaign aimed to systematically characterize the emissions and first 24 hours of smoke plume evolution from western U.S. wildfires. The project, led by Dr. Emily Fischer at Colorado State University, focused on three science questions related to better quantifying processes associated with fixed nitrogen, absorbing aerosols, and cloud activation and chemistry in wildfire plumes. WE-CAN deployed a large suite of measurement instruments run by both university and NCAR teams on the NSF/NCAR C-130 and also involved a ground-based mobile component.

The C-130 was based in Boise, Idaho from 20 July – 31 August 2018 to maximize the opportunities to sample smoke plumes from northwestern wildfires in California, Oregon, Washington, Idaho, Montana, Utah, Nevada, and Colorado during the peak of the 2018 fire season. All three sampling goals of WE-CAN were achieved. In all, during the 16 research flights based out of Boise, 21 different wildfire plumes were sampled, each with a detailed fuel assessment provided by the local regional Fire Service. Following the research science portion of the field campaign, a subset of the instruments were run during an educational component, involving three flights based out of Broomfield, Colorado over a two-week period in early September 2018. During these flights, the C-130 sampled smoke plumes from two more fires, including a prescribed fire in Colorado.

Several ACOM teams deployed measurement instruments on the C-130 for WE-CAN, including the Trace Organic Gas Analyzer (TOGA; PI Eric Apel, Rebecca Hornbrook, Alan Hills), the HIAPER Airborne Radiation Package (HARP) actinic flux measurement (PI Sam Hall, Kirk Ullmann), the PAN Chemical Ionization Mass Spectrometer (PAN-CIMS; PI Frank Flocke), a Picarro CO-CO2-CH4 instrument and an Aerodyne Research Inc. CO-N2O-H2O instrument (PI Teresa Campos), and the NO-NO2-O3 (PI Andy Weinheimer, Denise Montzka, Geoff Tyndall). Preliminary data submissions for most data sets are due by 15 November 2018, and final quality controlled data are due 15 March 2019. Preliminary analyses will be presented by many teams at a targeted session at the 21st Conference on Atmospheric Chemistry at the AMS Annual Meeting in Phoenix, Arizona in January 2019.

NSF smoke wildfire study
Aerial view of the Rabbit Foot Fire in Idaho on 13 Aug 2018. Smoke from the Rabbit Foot Fire was sampled by the NSF/NCAR C-130 during three separate WE-CAN research flights and several times for longer durations by ground-based mobile labs. (Photo credit: Rebecca Hornbrook)

Smoke creates record high pollution levels in California cities

The Camp Fire continues to affect air quality

smoke pollution particulates record California cities
Records show a large increase in particulates in some California cities after the Camp and Woolsey Fires started on November 8, 2018. Via @RARohde. Click to enlarge.

Areas in Northern California have been suffering through unprecedented air pollution since the Camp Fire started November 8 east of Chico. Sacramento, San Francisco, and Stockton have all recorded record high levels.

The animation below shows the predicted wind direction for Northern California at 9 a.m. PST November 19, 2018. If accurate, the wind could bring smoke from the Camp Fire, which is just east of Chico, down into the Sacramento Valley, the Bay Area, and the Central Valley on Monday. This condition should reverse Tuesday through Friday with the smoke being pushed to the north away from San Francisco, but Saturday could again bring wind and smoke from the north if the Camp Fire is still active.

On Sunday and Sunday night the Camp Fire was active on the east side and will likely produce a significant amount of smoke Monday. But Wednesday through Friday should bring copious amounts of rain to the fire area, perhaps more than two inches, which will definitely inhibit the production of smoke and slow the spread of the fire — at least.

The fatality count on the Camp Fire rose again Sunday as search teams found another set of human remains to bring the total loss of life to 77, with 993 unaccounted for. The current tally for the number of homes destroyed is 11,990, and acres burned, 151,000. The number of commercial structures burned rose from 367 to 472.

wildfire smoke forecast map
The forecast for the distribution of wildfire smoke at 2 p.m. PST November 19, 2018. NOAA.

Wildfire smoke and air quality maps, November 13, 2018

wildfire smoke forecast November 13 2018

Above is NOAA’s forecast for the distribution of wildfire smoke at 6 p.m. PST November 13, 2018. Much of Central and Northern California has severely compromised air quality and is in the “unhealthy” category.

Below is air quality data from for Tuesday November 13, 2018:

Air quality for November 13, 2018
Air quality for November 13, 2018.