What’s in the plume? Researchers compare health impacts of smoke from wildfires versus prescribed burns

What’s in the plume? Researchers compare health impacts of smoke from wildfires versus prescribed burns

What’s in the plume?

Scientists compare health impacts of smoke from wildfires versus prescribed burns.
Reno, Nev.
October 26, 2020

Human health
Wildfire smoke

Featured research by DRI’s Andrey Khlystov, Dante Staten, Jim Metcalf, Adam Watts, Vera Samburova, Siying Lu, and Hans Moosmuller.

When the air over Reno and other western communities turns hazy-brown with wildfire smoke, many can’t help but wonder – what is in the smoke, and can it make us sick? Desert Research Institute (DRI) scientists Andrey Khlystov, Ph.D., Dante Staten, M.S., and a team of colleagues from DRI and the University of Nevada, Reno (UNR) are currently working to find out, as part of a five-year project funded by the National Institutes of Health.

The project, which began in 2019, will compare the impacts on human health of two different types of fire smoke – smoke from wildfires versus that from prescribed burns. Although each can generate large plumes of smoke, wildfires often burn hotter and their plumes may include chemicals released by burning houses or other structures.

“Prescribed fires do still generate smoke, but they are usually lower intensity fires, so they generate different amounts of pollutants and different kinds of particles to some extent,” Khlystov said. “So, our study is asking, what is the relative benefit to health of managing land with prescribed fires? Or, is prescribed fire and wildfire smoke about the same?”

DRI researchers collect data from air quality monitoring station on DRI rooftop

DRI scientists Dante Staten (left) and Andrey Khlystov (right) collect air quality data from sensors located on the roof of the Desert Research Institute in Reno. October 19, 2020.

Credit: DRI.

In 2019, Khlystov, Staten and their colleagues began collecting and analyzing air samples at Environmental Protection Agency (EPA) monitoring sites in Reno and Sparks, as well as on the DRI rooftop. They have continued to collect air quality samples during summer and fall of 2020.

“Last year our air was pretty clean – unlucky for the project, but lucky for everyone else,” Khlystov said. “But this year, from about mid-August to mid-September, we had almost non-stop smoky days.”

Staten, a graduate research assistant and Ph.D. student with UNR’s environmental science program, has been heavily involved in sample collection during his time at DRI. With more than 150 air quality samples now in hand, he is beginning to process and analyze them in DRI’s Organic Analytical Lab.

air quality monitoring equipment
researchers at air quality monitoring station on DRI roof

Above: Using air quality monitoring equipment located at sites in Reno and Sparks, DRI researchers have collected more than 150 air quality samples during the 2020 season. The photos above were taken from the DRI rooftop in 2019 and 2020.

Credit: DRI.
Next, Khlystov and his team plan to conduct laboratory experiments in DRI’s combustion chamber in order to learn more about the specific air quality impacts of burning different fuel types collected from around Reno and other parts of the Sierra Nevada and California, and to learn about how the chemical composition of smoke changes over time. They will use this data and information to create a model of the pollutants present in smoke plumes.  

Working in collaboration with epidemiologist Matt Strickland, Ph.D., of UNR, the researchers will then compare information from the air quality model with a database of health records provided by Renown Health. This will allow the team to investigate impacts of smoke on human health in terms of number of hospital visits that occurred during wildfire or prescribed fire smoke events.  

“Renown has millions of health records, all anonymized so that there are no privacy issues, but we can use them to see how many people have health complaints after an episode of wildfire or prescribed fire smoke,” Khlystov explained. “This will allow epidemiologists to figure out how bad an impact was – for example, if we have an increase in smoke particle concentration by a factor of two, does that mean 100 more people coming to the hospital, or 1,000, or 10,000?” 

Researchers analyze air quality samples in DRI's organic analytical laboratory.

Researchers Dante Staten (left) and Andrey Khlystov (right) analyze air quality samples in DRI’s Organic Analytical Laboratory. October 19, 2020.

Credit: DRI.

As climate change continues to alter natural fire regimes, Khlystov, Staten and their colleagues hope that their study findings will provide needed information to help everyone from land managers to the medical community and individual citizens better manage risk during the fire season.

“The incidence of wildfires here in the west and around the world is increasing, it’s very difficult not to notice,” Khlystov said. “People know that the particles are not good for you and are causing all sorts of health effects, but there are still a lot of unknowns.”

Additional information

For more information on this study, read the project summary: Associations of smoke from wildfires and prescribed burns with cardiorespiratory health outcomes in Reno, NV 

To view realtime air quality data from the rooftop of Desert Research Institute’s Reno campus, visit the Purple Air Network’s air quality map: https://www.purpleair.com/map?opt=1/mAQI/a10/cC0#10.94/39.5768/-119.8067

DRI Video – Wildfire Smoke, Air Quality, & Public Health  

Tiffany Pereira works at Tule Springs
During August and September of 2020, smoke drifted into Nevada from numerous California wildfires. This satellite image shows extremely smoky conditions on September 14, 2020
Credit: NASA Worldview.

Sushi Time! Lab outing to welcome a new postdoc Ting Zhang

Sushi Time! Lab outing to welcome a new postdoc Ting Zhang

We had lunch at the OAL’s favorite sushi place today to welcome Dr. Ting Zhang to the lab. Ting will be working with Dr. Andrey Khlystov at DRI and Dr. Sergey Varganov at UNR to study thermal decomposition of e-cigarette flavorants. Her project has both laboratory and modeling components. Welcome, Ting!

Hazardous chemicals discovered in flavored e-cigarette vapor

Hazardous chemicals discovered in flavored e-cigarette vapor

Scientists stress need for thorough research into flavored e-liquids

RENO – Building on more than 30 years of air quality research in some of the most polluted urban environments on Earth, a team of atmospheric scientists at the Desert Research Institute (DRI) has turned their attention toward the growing e-cigarette industry and the unidentified effects of vaping on human health.New research published today in Environmental Science & Technology (ES&T), a journal of the American Chemical Society, reports that the aerosols (commonly called vapors) produced by flavored e-cigarettes liquids contain dangerous levels of hazardous chemicals known to cause cancer in humans.

The study “Flavoring compounds dominate toxic aldehyde production during e-cigarette vaping” confirms that these toxic aldehydes, such as formaldehyde, are formed not by evaporation, but rather during the chemical breakdown of the

“How these flavoring compounds in e-cigarette liquids affect the chemical composition and toxicity of the vapor that e-cigarettes produce is practically unknown,” explained Andrey Khlystov, Ph.D., an associate research professor of atmospheric sciences at DRI. “Our results show that production of toxic aldehydes is exponentially dependent on the concentration of flavoring compounds.”

E-cigarette liquids have been marketed in nearly 8,000 different flavors, according to a 2014 report from the World Health Organization. Recent reports have shown that many flavors, such as Gummy Bear, Tutti Fruitty, Bubble Gum, etc., were found to be especially appealing to adolescents and young adults.

The U.S. Food and Drug Administration (FDA) reports that 16-percent of high school and 5.3-percent of middle school students were current users of e-cigarettes in 2015, making e-cigarettes the most commonly used tobacco product among youth for the second consecutive year. In 2014, 12.6-percent of U.S. adults had ever tried an e-cigarette and about 3.7-percent of adults used e-cigarettes daily or some days.

Khlystov and his colleagues measured concentrations of 12 aldehydes in aerosols produced by three common e-cigarette devices.

To determine whether the flavoring additives affected aldehyde production during vaping, five flavored e-liquids were tested in each device. In addition, two unflavored e-liquids were also tested.

“To determine the specific role of the flavoring compounds we fixed all important parameters that could affect aldehyde production and varied only the type and concentration of flavors,” explained Vera Samburova, Ph.D., an assistant research professor of chemistry at DRI.

Samburova added that the devices used in the study represented three of the most common types of e-cigarettes – bottom and top coil clearomizers, and a cartomizer.

The study avoided any variation in puff topography (e.g., puff volume, puff velocity, interval between puffs) by utilizing a controlled sampling system that simulated the most common vaping conditions. E-cigarette vapor was produced from each device by a four-second, 40-ml controlled puff, with 30-second resting periods between puffs. The e-cigarette devices were manually operated to replicate real-life conditions and all samples were collected in triplicate to verify and confirm results. Specific care was taken to avoid “dry puff” conditions.

e-cigarettes provide further proof that the flavoring compounds, not the carrier e-liquid solvents (most commonly propylene glycol and/or vegetable glycerin) dominated production of aldehydes during vaping, the authors performed a series of experiments in which a test flavored e-liquid was diluted with different amounts of the unflavored e-liquid. Liquids with higher flavor content produced larger amounts of aldehydes due to pyrolysis of the flavoring compounds.

In all experiments, the amount of aldehydes produced by the flavored e-cigarette liquids exceeded the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs) for hazardous chemical exposure.

“One puff of any of the flavored e-liquids that we tested exposes the smoker to unacceptably dangerous levels of these aldehydes, most of which originates from thermal decomposition of the flavoring compounds,” said Khlystov. “These results demonstrate the need for further, thorough investigations of the effects of flavoring additives on the formation of aldehydes and other toxic compounds in e-cigarette vapors.”

This research was independantly funded by the Desert Research Institute and conducted in DRI’s Organic Analytical Laboratory located in Reno, Nevada.

“Flavoring Compounds Dominate Toxic Aldehyde Production During E-cigarette Vaping”

DOI # – 10.1021/acs.est.6b05145 – http://pubs.acs.org/doi/abs/10.1021/acs.est.6b05145


E-cigarette sampler

DRI scientists used a controlled sampling system to simulate the most common vaping conditions. E-cigarette vapor was produced from each device by a four-second, 40-ml controlled puff, with 30-second resting periods between puffs. Credit DRI.

E-cigarette vape devices and juice

DRI scientists measured concentrations of 12 aldehydes in aerosols produced by three common e-cigarette devices shown here. Credit DRI


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