The median diameter of vaping particles falls around 200 to 300 nanometers, based on unpublished data from Jonathan Thornburg and others at RTI International in Research Triangle Park, N.C. That size “is right in line with conventional tobacco smoke,” Thornburg says.
The mass of particles in the vapors is about 3 milligrams per cubic meter of air, he says, or about 100 times as high as the Environmental Protection Agency’s 24-hour exposure limit for levels of fine air particles. Thornburg’s group’s analyses predict that some 40 percent of these inhaled particles would deposit in the lungs’ smallest, deepest airways.
In addition to nicotine and solvents, vapors also contain chemical flavorings and food preservatives from the vaping liquid. Although they may be GRAS, or “generally recognized as safe” by FDA, Thornburg says, the designation is based on tests of the compounds when they are ingested. “No one has considered their safety when it comes to inhalation,” he says.
The median diameter of vaping particles falls around 200 to 300 nanometers, based on unpublished data from Jonathan Thornburg and others at RTI International in Research Triangle Park, N.C. That size “is right in line with conventional tobacco smoke,” Thornburg says.The mass of particles in the vapors is about 3 milligrams per cubic meter of air, he says, or about 100 times as high as the Environmental Protection Agency’s 24-hour exposure limit for levels of fine air particles. Thornburg’s group’s analyses predict that some 40 percent of these inhaled particles would deposit in the lungs’ smallest, deepest airways.In addition to nicotine and solvents, vapors also contain chemical flavorings and food preservatives from the vaping liquid. Although they may be GRAS, or “generally recognized as safe” by FDA, Thornburg says, the designation is based on tests of the compounds when they are ingested. “No one has considered their safety when it comes to inhalation,” he says.
การแปล กรุณารอสักครู่..