Glenn Morrison, Ph.D., is anxiously waiting for the day he will get to his 1,000 samples of urine that have been stashed away in a refrigerator for close to a year now because of the COVID-19 pandemic. The bottles might be holding answers to questions that have puzzled him over the years—the number of chemicals the human skin can absorb from clothes that are hanging, not just in closets, but in basements and storage boxes, for example.
“We had these individuals wear clothing that was very clean for a day and then changed them for another (clean) set the next day … we had their urine for when they did that and after,” he says. He anticipates seeing a dramatic drop in some chemicals in the urine. “Unfortunately, I can’t report results because the lab we are using was shut down (due to the pandemic).”
Morrison, who is also a AAAS Member, investigates how these everyday chemicals, for example in clothing or cleaning supplies, can move through the environment and interact with one another, and also through the bodies of people in their indoor environments.
“I see the world through the lens of chemical engineering,” he says. “I have made progress on indoor surface chemistry and transport of chemicals through the environment and ultimately to us…even this clothing stuff that we have been doing in the past five years is a chemical engineering problem, it’s just membranes and chemicals transporting across membranes.”
Morrison who currently works as a professor at the Environmental Sciences and Engineering Gillings School of Global Public Health at the University of North Carolina Chapel Hill was originally drawn to his research for altruistic reasons. “I worked as a chemical engineer for a while and I became interested in environmental work in general because it made sense to me that we need to be good stewards of our environment,” he says.
His research papers help explain his work, for example, a 2016 paper — Role of clothing in both accelerating and impeding dermal absorption of airborne SVOCs — was published in Nature’s Journal of Exposure Science and Environmental Epidemiology. In his study, Morrison and his colleagues explain how “…fabrics that are exposed to building air for extended periods (e.g. hanging up in a closet) may absorb a substantial quantity of Semi-Volatile Organic Compounds (SVOCs).”
These findings then lead to public health questions that need more research and study. Morrison is careful in how he approaches these issues, even when it comes to giving advice to curious people who want to learn more about his work, and naturally, how it might apply to their own health.
“I don’t tell anybody to do anything differently, although, for friends of mine who have babies, I say if you want to do anything when you wash your clothes dry them outside,” he says. He explains that’s because the concentrations of the kind of chemicals (for example clothing dyes, or plastic materials, like polyester) that are most likely to pass through the skin from clothing are much lower outdoors than indoors
“What you are doing is pushing the overall chemical activity in your clothing to near zero,” he says.
The only time Morrison departs from his argument is when it comes to, for example, military clothes that have been soaked in permethrin insecticide that kills or repels mosquitoes. “This gets to the larger philosophical question of what kinds of situation is it acceptable to expose people to higher levels of chemicals that we know have a beneficial use,” he says. “It makes sense and you can do it in a very targeted way.”
There are other common chemicals like nicotine which Morrison has found under his microscope. Nicotine is readily absorbed in what Morrison refers to as the air-to-skin-to-blood pathway.
“Tobacco harvesters, who neither smoked nor chewed tobacco, have been found to have elevated levels of urinary cotinine, a nicotine metabolic, after handling green tobacco leaves,” he and his colleagues wrote in a 2016 research paper, Measurement of Dermal Uptake of Nicotine Directly from Air and Clothing.
Morrison and his colleagues’ study concluded that the continued excretion of nicotine and its metabolites within bare-skinned participants after 60 hours indicated that human skin acts as a reservoir, delivering nicotine to the blood long after exposure. That means clothes are a good barrier in halting this transfer.
From personal care products to clothes in a closet, a consistent line that emerges from the studies that Morrison has conducted over the years is that his findings have shown a direct impact on human life. But more institutional investment is needed, Morrison says, whether from the Federal Government or states, to better explore the impact on human health. He calls the amount of funding for the research associated with indoor environments “tiny”, particularly considering how much time people spend indoors.
“Anything that is manufactured that has stuff in it…plasticizers, flame retardant, stabilizers and pigments, detergents, emulsifiers—all these things add to this chemical stew in your home or in any building,” he says. “To some degree, the chemical stew is also due to people, because our bodies also increase the amount (of chemicals) that are in the air. That is why we can make a house stink.”