EVIDENCE: MODERATE (emerging field) Thirdhand exposure refers to chemical residue left on surfaces after vaping. A 2025 study in Environmental Science & Technology found:

• Nicotine deposits on walls, furniture, and clothing at 0.5-5.0 ug/cm2 in homes where indoor vaping occurs regularly
• PG/VG residue forms a sticky film on surfaces (less persistent than tobacco tar but still present)
• Flavoring compounds (diacetyl, cinnamaldehyde) detected on surfaces in rooms where flavored e-liquid was vaped
• Persistence: nicotine residue remains on surfaces for weeks to months — it does not dissipate as quickly as airborne aerosol
• Re-emission: deposited nicotine can re-enter the air when surfaces are touched, warmed, or cleaned

The health risk from thirdhand exposure is still being studied. The CDC notes it may be a concern for infants who crawl on floors and put their hands in their mouths. This is an active area of research — current evidence is insufficient to quantify the risk, but it is not zero. For more on e-liquid chemistry and degradation, see our vape juice storage guide.