(Reuters Health) - Nicotine and other chemicals exhaled by e-cigarette smokers can move through air vents, leaving residue on surfaces in other locations, a new study found.

In a California mall, researchers tracked e-cigarette chemicals from a vape shop and found the residue in a business next door.

Although studies have identified the chemicals in vaping fluids and in the aerosol users breathe in, little is known about what’s exhaled and what settles on surfaces, said Careen Khachatoorian of the University of California at Riverside, who led the study.

“Electronic cigarettes and refill fluids seem to be evolving and new products are brought to the market every day,” she told Reuters Health by email. “The scientific community should keep up with these new products to inform users, non-users and especially people who do not know they are being passively exposed.”

In a two-story mall with a vape shop on the bottom floor, Khachatoorian and colleagues analyzed the build-up of e-cigarette exhaled aerosol residue in cotton towels, paper towels and terrycloth towels that they placed around the vape shop and in an adjacent shop with a connected HVAC system.

They tested the towels for short-term exposures of one day, four days and eight days and long-term exposures after one month, two months and three months. They specifically looked for nicotine, other alkaloids and tobacco-specific nitrosamines, which have been linked to carcinogens.

They also placed fabrics in a mall hallway on a separate HVAC system for one day, three days and one week.

They found nicotine, alkaloids and nitrosamines in the towels in the adjacent shop after both short-term and long-term exposures. The concentrations generally increased over time, according to a report in the journal Tobacco Control.

Even samples exposed for one day had detectable nicotine. The control samples - the towels placed in the mall hallway - had no traces of nicotine.

“(Analogous) to thirdhand smoke, electronic cigarette aerosol or residue can occur during and after use has ended,” Khachatoorian said. “Unlike cigarette smoking, we do not yet know the long-term health effects of e-cigarette use and passive use.”

The researchers plan to study the residue left by e-cigarette aerosol and identify more chemicals and quantities of chemicals that stick to surfaces.

Future studies should also understand what harms are associated with secondhand and thirdhand exposure, said Eric Soule of East Carolina University in Greenville, North Carolina.

Soule, who wasn’t involved with this study, researches indoor e-cigarette use and has found it generates large amounts of particulate matter, which could be harmful to inhale. Researchers need to understand the short-term and long-term effects, he added.

“Regardless of the harm caused from exposure to e-cigarette aerosol relative to cigarette smoke, policies should be established that protect non-tobacco users from exposure to e-cigarette aerosol, especially in public places or private residences,” he told Reuters Health by email.

In a mall, for instance, a vape shop could be required to use a special air filter and separate ventilation system, Soule said.

“While many cigarette smokers avoid smoking indoors or around non-smokers because of the known health effects of secondhand and thirdhand smoke exposure, many e-cigarette users report vaping in their cars, in their homes or around their children and pets,” he said. “Given the deposition of toxicants that results from indoor e-cigarette use, vapers should similarly avoid e-cigarette use indoors or around others.”

SOURCE: bit.ly/2O153y5 Tobacco Control, online August 29, 2018.