Assessing fentanyl and methamphetamine in air and on surfaces of transit vehicles.

Recently, the misuse of fentanyl and methamphetamine has increased in the United States. These drugs can be consumed via smoking a powder, which can subsequently contaminate air and surfaces with drug residue. With limited access to safe consumption sites, this misuse often occurs in public spaces such as public transit, leading to potential secondhand exposures among transit operators and riders.