This preliminary study indicates that meaningful dermal uptake of nicotine directly from air can occur. Dermal uptake for bare-skinned participants was comparable to calculated inhalation uptake if the latter had occurred. The concentrations of nicotine and metabolites in the urine of participants were similar to non-smokers working in hospitality environments as well as light smokers. Clean clothes decreased the uptake compared to bare-skinned exposure. Wearing an ETS exposed shirt resulted in a roughly four times larger uptake than that with clean clothes. However, the resulting uptake was still substantially lower than for the bare-skinned participants.
The continued excretion of nicotine and its metabolites after 60 hour indicates that skin acts as a reservoir, delivering nicotine to blood long after exposure. This delayed uptake may point to some ionization occurring at the skin's surface. However, the total nicotine uptake suggests that ionization does not substantially impede uptake.
In the near future, we plan to conduct more detailed studies with a larger number of participants, more controlled concentrations using pure nicotine (instead of ETS), a longer exposure period, and urine collection over a longer time interval. Better understanding of dermal absorption of nicotine will lead to more complete assessments of nicotine exposure. This is especially important for infants and children in homes where smoking or vaping occurs.