You know that nail salon smell? That sharp hit of chemicals, the strangely sweet scent of polish, the faint tingle in your nose? That’s air pollution, and it’s been linked to a variety of experienced by the workers who breathe it. Nail salon workers commonly experience irritated skin and eyes, headaches, loss of smell and respiratory problems.����

Officials in some cities and states, including Washington, have introduced new regulations designed to better protect nail salon workers — .��

But the mysteries around what, exactly, causes those potent smells make protecting these workers more difficult. Cosmetics manufacturers are rarely required to disclose what specific chemicals they use to scent their products, which has hindered efforts to better understand the air that salon workers breathe. ��

, a UW assistant professor of environmental and occupational health sciences, set out to solve the mystery. In a study published , Ceballos and her co-authors analyzed the air in a group of nail salons around Boston — where Ceballos previously worked at Harvard University — and identified 18 distinct fragrance chemicals. It’s the most comprehensive study to date of the specific fragrance chemical mixtures found in nail salon air, and will allow researchers to further study the potential health risks.

UW News sat down with Ceballos to discuss the findings of the study, the mysteries around fragrance chemicals and how to better protect nail salon workers’ health.����

Nail salons are a bit of a research specialty of yours. You’ve published papers on , workers’ exposure to “old” and as well as “” harmful chemicals, and the . How did you come to focus on nail salons and their workers? ��

Diana Ceballos: I started working on nail salons soon after I read a back in 2015. It won all sorts of awards. When that story came out, it created havoc. I was working at the Centers for Disease Control and Prevention at the time, and the New York Health Department asked for technical assistance because they were horrified by the conditions in nail salons. I was put on the team partly because I’m an industrial hygienist, but also because I speak Spanish, and there are a lot of Spanish-speaking workers in these salons.����

Then my life changed, and I went back to academia. I just knew there was more we could be doing. There was just so little research in this area, it was incredible. So, I decided I wanted to focus on nail salons. In the meantime, a lot of other people had the same idea, so lots of different groups around the country and internationally have started working on this.����

What are fragrance chemicals, and what do we know about them? ��

DC: Fragrances are added to nail salon products to create a desired smell — lotion that you want to smell like lavender, for example — but many fragrances are used to mask undesired smells. A lot of nail products have very strong, not-so-good smells, so companies add fragrances to mask those smells. But then you have even more scented chemicals in the air!��

A good number of fragrances are known sensitizers. That doesn’t only cause irritation on the skin, but, for example, some fragrances could trigger an asthma attack if inhaled. Or, if they’re a sensitizer, they could even help cause asthma and other respiratory complications. It’s not just the skin, it’s the entire immune system. And that’s just the effects that we know of.��

There are also some positive effects from fragrances. It’s well-known that some fragrances can be relaxing or affect the ambiance of an environment. But that hasn’t been well-studied. Some of these chemicals are very little-known. They could be toxic, but we don’t know. They’re just used in small amounts to produce fragrance, and for the most part, chemical regulations have been focused on bigger culprits. It’s just in the last decade or so that officials have paid attention to chemicals that show up in smaller quantities, like fragrances.��

For a very long time, fragrances were trade secrets, and specific chemicals weren’t listed as ingredients. Labels just said ‘fragrance.’ In the last 10 years, chemical regulations in Europe and in some states have introduced more discrimination of toxic chemicals that could include fragrances, but there’s a lot of work still to disclose the ingredients. For example, in the new cosmetics bill in Washington, there’s more information required on ingredients lists. That was already the case in California, for example, but it’s just starting. We aren’t the first ones to ever measure them, but to our knowledge we’ve measured the biggest number of fragrances. Also, our analysis suggests that not only nail products are contributing to fragrances, but also other products in the salons such as personal care products and cleaning agents are potential emission sources.��

Many people can identify the strong scent of a nail salon, but I’m not sure we consider that we’re actually smelling air pollution. How does that pollution affect nail salon workers?����

DC: Indoor air quality is important for anyone. The quality of our health depends on the air that we breathe. Even for a customer, nail salons are very fragrant and have many odors. Some people are very sensitive to odors. Even just talking about the odor itself can trigger a lot of health effects. People can get headaches, dizziness, and get nauseated. So, there are people that don’t go to nail salons because they can’t be in there. And that’s a customer. Imagine the workers. ��

There are people who have to do this work because they don’t have training in anything else, and in surveys of the health of people who work in nail salons, it’s fairly prevalent to have headaches, irritation, fussiness — all the typical symptoms of odors, let alone toxic chemicals. It can deteriorate your well-being and quality of life, especially as some of these workers are on 12-hour shifts, seven days a week. So, it’s significant, the amount of time they’re exposed to these fragrances along with many other toxic chemicals.��

You note throughout your research that the air pollution in nail salons is something that can affect the air we all breathe — even if we never visit a salon. How is that possible?��

DC: It’s very important to lower chemical concentrations indoors because they eventually go outside and contribute to overall air pollution. It’s hard to control that in small businesses, but one thing that was clear when Boston was building a ventilation policy was that it was important to make sure businesses filtered out chemicals before they went out the window. Now we know that fragrances make up a considerable part of overall chemicals in nail salons and they’re adding to the mix. And since you have fragrances in a bunch of products, it all adds up. We must consider the accumulated burden that fragrances can have in the indoor environment and put more purposeful thought into how we produce products that contain those things — not just during the life cycle of the products, but also how they interact with the environment. ��

There are policies right now that are trying to work on fragrances, but we need to learn more. It’s going to be a while before we can control or guide manufacturers better. It’s very early, but I think there’s a lot we can learn about fragrances in the future.��

Other authors on the June 19 paper are Chunrong Jia and Xianqiang Fu of the University of Memphis and Thomas Webster of Boston University.����

For more information or to reach Ceballos, contact Alden Woods at acwoods@uw.edu.��

Across the American West, managers of fire-prone landscapes are increasingly using a practice that seems counterintuitive: setting small fires to prevent larger, more destructive ones. Commonly called “prescribed burns,” these targeted, controlled fires keep forests healthy by reducing the buildup of grasses, leaves, branches, and other debris that can fuel larger wildfires and smoke out nearby communities.����

But smoke from prescribed burns also presents health risks. Today’s forest managers must ask themselves — how much prescribed burning is too much? When do the long-term benefits of fuel reduction no longer outweigh the short-term smoke costs? And how can nearby communities better prepare for a fire season?����

An international team led by researchers at the ����Ӱ�Ӵ�ý built a framework to help land managers assess the air quality implications of land management scenarios with different levels of prescribed burning. To apply the framework, researchers��linked together a series of models that estimate the smoke effects of various levels of prescribed burning on ecosystems and nearby communities.����

After using those models to estimate the smoke produced under six different levels of prescribed burning across California’s Central Sierra range, the researchers found that moderate amounts of burning would reduce overall smoke levels. All tested levels of prescribed fires led to less wildfire smoke overall. But greater amounts of prescribed fires could present notable health hazards of their own.����

The researchers reported their findings — specific to the Central Sierra landscape — in a pair of recently published papers. The first, , estimated how different levels of prescribed burning affected the total amount of smoke produced during an average wildfire season. The second, , analyzed the impacts on the region’s outdoor agricultural workers.��

“We haven’t had a good way to put numbers to that smoke exposure trade-off previously because of challenges in integrating data and methods across sectors,” said , a UW doctoral alum of the Department of Environmental & Occupational Health Sciences and lead author of both papers. She is now a postdoctoral scholar at UCLA. “We know that if we can reduce fuel density, then wildfires may be less severe when they do come through. Emissions may also be lower, and thus subsequent smoke exposure and health impacts will be less. We also must consider that the location and timing of prescribed burns are planned, which is not the case for wildfires. That’s the concept. But I think communicating that has previously been difficult.����

“What’s cool about this work is we were finally able to quantify the trade-off between reducing wildfire risks and its impacts on human health through prescribed burning at a local scale.”��

Researchers focused on the Tahoe Central Sierra Initiative, a 2.4 million acre expanse covering public, private and commercial land. A consortium of land managers in the area developed six forest management scenarios with increasing levels of prescribed burning. They ranged from Minimal Management, with no prescribed burns and limited efforts to trim back excess fuels, to a scenario dubbed Fire++, with an estimated 30,000 acres of prescribed burning each year.����

Those scenarios were fed into a series of models that estimated the amount of smoke generated by wildfires and prescribed burns in each scenario, and the health impacts on nearby communities.����

Every scenario that included prescribed burning in the Tahoe Central Sierra Initiative resulted in a shorter wildfire smoke season, with less overall smoke, than those without prescribed burns. As a result, nearby communities and outdoor agricultural workers could be exposed to less smoke.����

The model predicted that overall smoke levels as measured by concentrations of fine particles (PM 2.5) were lowest with a moderate amount of prescribed burning — a scenario researchers called, simply, Fire. Scenarios that involved greater amounts of burning — Fire+ and Fire++ — produced slightly more total smoke than the moderate scenario. ��

Schollaert hopes forest managers across the country will replicate the methods, so they can better incorporate public health considerations into management planning on their specific landscapes.��

“The exact placement of that sweet spot of prescribed burning is going to vary. But when mitigating extreme wildfire risk, the more you can lower severity of fire, the lower your emissions are going to be, generally,” Schollaert said. “And baked into that sweet spot is also coordination with health agencies, because you can theoretically plan for smoke from prescribed burns. That’s the kind of planning I’m hoping can come from this.”��

Other authors on both papers include and of the UW Department of Environmental & Occupational Health Sciences; of the UW School of Environmental and Forest Sciences and of the UW Department of Civil and Environmental Engineering, among others.����

Research for the Nature Sustainability paper was funded by Science for Nature and People Partnerships. Research for the Environmental Research Letters paper was funded by NASA and the U.S. Department of Energy.��

For more information, contact Schollaert at cschollaert@ucla.edu.��

Two years ago, as life regained its rhythm and public transit once again filled with people, train and bus operators spotted a troubling trend. Some operators reported instances of people smoking drugs on their vehicles, and worried that the haze it created could linger, potentially affecting workers’ physical and mental health.��

Spurred by operators’ concerns, five transit agencies in Washington and Oregon approached researchers at the ����Ӱ�Ӵ�ý with a yes-or-no question: Were transit operators being exposed to drug smoke or residue in their workplace?����

The answer is nuanced. A UW research team conducted a limited-scope, first-of-its-kind assessment and detected fentanyl and methamphetamine on board numerous transit vehicles, both in the air and on surfaces. But nearly all of the positive samples contained small amounts that are unlikely to cause acute medical conditions. And it remains unclear if consistent, long-term exposure — such as that potentially faced by operators working a 40-hour week — poses a risk to worker health.��

“A work environment that includes drug use and drug smoke can make it harder for transit operators to safely and effectively do their jobs, regardless of the level of exposure that operators may face,” said , a UW assistant professor of environmental and occupational health sciences who co-led the assessment. “This research is important, as it draws attention to the stressors and exposures that these essential workers face.” ��

A complete accounting of the project, including research methods and detailed results, is available in the researchers’ The findings from this assessment are not yet submitted for publication. ��

The assessment was limited in scope and narrowly tailored. Researchers collaborated with five transit agencies, which also provided funding: , , and in Snohomish County, and in the Portland metro area.��

Air and surface sampling took place on trains and buses from four agencies and over 28 nights earlier this year. Transit lines and times were selected for sampling based on operator reports of observed drug use, with researchers targeting routes and runs when smoking events were most likely to occur. Both air and surface samples were collected near operators and in other areas of the vehicles where smoke was likely to accumulate.����

The assessment did not explore whether operators had any level of secondhand fentanyl or methamphetamine in their bodies. It also did not attempt to examine all transit routes and times, and researchers said their findings should not be assumed to be typical for all transit vehicles at all times.��

Researchers detected methamphetamine in 98% of surface samples and 100% of air samples, while fentanyl was detected in 46% of surface and 25% of air samples. One air sample exceeded . No similar guidelines exist for airborne methamphetamine.��

No enforceable federal or state regulations exist for either fentanyl or methamphetamine exposures in a workplace.����

The detection of fentanyl or methamphetamine by the lab does not necessarily mean it poses a health risk to operators or the riding public, Baker said.����

No previous studies have demonstrated acute medical conditions resulting from passive exposure to fentanyl or methamphetamine at the levels seen in this study, such as from touching contaminated surfaces or inhaling secondhand smoke. But further consideration should be given to daily secondhand exposure experienced by operators and its potential for long-term health effects, which have yet to be established by evidence-based research.����

“Operators are different from the riding public, because operators are exposed for a much longer time period,” said , a research industrial hygienist in the UW Department of Environmental & Occupational Health Sciences and co-leader of this assessment. “The potential long-term health effects associated with daily exposure have not been adequately researched, so until these relationships are established, we’re suggesting protective measures that transit agencies could implement to keep operators safe.” ��

Those mitigation measures include enhanced cleaning of surfaces, upgraded ventilation and filtration where possible, and operator training. Training topics could include how operators should respond to smoking on board, real and perceived risks of secondhand drug exposure and how and when to use naloxone (Narcan) in overdose emergencies.����

Researchers also emphasized the need to consider operators’ mental health, especially for those in recovery or who may have experienced trauma related to drug use. ��

“Even at a level that is considered ‘safe,’ it can still be stressful to see drug use in your workplace,” Baker said. “Taking steps to protect operators will benefit their physical and mental well-being at work.”��

, a clinical assistant professor of environmental and occupational health sciences, also co-authored the final report. This assessment was funded through a contract with Sound Transit. King County Metro, Community Transit, Everett Transit, and TriMet, in addition to Sound Transit, contributed funding.��

For more information or to contact the researchers, email Alden Woods at acwoods@uw.edu.��