People can
continue using mineral-based aerosol sunscreens without fear of exposure to
dangerous levels of nanoparticles or other respirable particulates, according
to Penn State research published in the journal Aerosol Science and
Engineering.
The
findings, reported by a research team led by Jeremy Gernand, associate
professor of industrial health and safety, are a result of experiments
conducted using three aerosol sunscreens commonly found on store shelves.
Gernand's
team simulated the application process for someone using the recommended amount
of sunscreen and analyzed the released aerosols. They chose mineral-based
sunscreens with silicon dioxide, zinc oxide or titanium dioxide as the active
ingredient over chemical-based sunscreens because those are more commonly
recommended for children and the ingredients are deemed safe by the U.S. Food
and Drug Administration.
"We
simulated what we considered to be a worst-case scenario for someone being
exposed to aerosolized nanoparticles while applying sunscreen, and that
scenario is a person applying it to their arms because the spray is so close to
their face," Gernand said. "And then we pulled air samples from that
location."
The goal
of the research was to determine the size and concentration of aerosol
particles at the location of a realistic breathing zone for the user, and to
determine if those factors posed potential health risks.
The team
did find trace nanoparticles of the active ingredients but the amounts were
hundreds of times less than the National Institute of Occupational Safety and
Health recommended exposure limit. Gernand said previous studies that pointed
to dangerous exposure to nanoparticles missed the mark because they relied on
an analysis of the contents, rather than field tests. The FDA completed a study
on the safety of sunscreens in 2019.
Although
only three products were studied, Gernand said it's unlikely other products
would produce vastly different amounts of nanoparticles. Researchers found all
three products to be similar in aerosolized particles produced.
"For
a massive increase in particle exposure, the canister design would have to be
dramatically different and most likely so would the amount of and size of the
active ingredients inside," Gernand said. "Based on these results, I
would be surprised to find variations in brands or formulations that amounted
to hundreds of times more exposure. It's just too far away from what we
observed."