Smokescreen:Are E-Cigarettes Safe?
Television advertiments for cigarettes have been banned in the U.S. since 1971, but in the past few years suppodly healthier,battery-powered alternatives have landed numerous prime-time
appearances.
The concept behind e-cigs is clever: they allegedly offer all the fun of typical cigarettes without any of the dangers. E-cigs u a small, heated coil to vaporize a nicotine-laced solution into an aerosol mist. By inhaling the niist, urs enjoy the same satisfaction they would get from an ordinary cigarette but do not expo themlves to tobacco, which turns into cancer-causing tar when it is burned.flag day
But are e-cigs truly safe? No one knows for sure. Yet there is no question that the nicotine they contain is addictive —which is one reason many public health experts have grown alarmed by their rapidly increasing popularity. Among their concerns: e-cigs might lure form
会计凭证的填制er smokers back to conventional cigarettes, expo urs and bystanders alike to unidentified dangers, or become a gateway for teens who might subquently experiment with tobacco products and other drugs.
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The current iteration of e-cigarettes was invented and popularized by Chine pharmacist Hon Uk in 2003 and entered the U.S. market some ven years ago. In lieu of carcinogenic tobacco, e-cigarettes typically contain three main ingredients: nicotine, a flavoring of some kind and propylene glycol — a syrupy synthetic liquid added to food, cosmetics, and certain medicines to absorb water and help them stay moist. The primary established danger of nicotine is that the stimulant is highly addictive, although emerging science also links it to an impaired immune system. Propylene glycol has been ,4generally recognized as safe," or GRAS (an official FDA designation), since 1997. Yet more needs to be understood before e-cigarettes can be a given a clean bill of health.
Propylene glycol, for example, is usually eaten (in cupcakes, soft drinks and salad dressi
ngs) or slathered onto the body (in soaps, shampoos and antiperspirants) — not breathed into the lungs. Many things that can be safely eaten 一 such as flour — can damage the lungs when inhaled. No one knows whether propylene glycol falls into that category. "We have little information about what happens to propylene glycol in the air,” the federal Agency for Toxic Substances and Dia Registry says on its Website.
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Beyond the three main ingredients, some rearchers worry about by-products from heating electronic cigarettes and the solution inside them. Various studies suggest the vapors from e-cigarettes contain veral cancer-causing substances, as well as incredibly tiny particles of tin, chromium, nickel and other heavy metals, which, in large enough concentrations, can damage the lungs. Becau they are so small, the tiniest bits of metal, known as nanoparticles, can travel deep into the lungs. There they could exacerbate asthma, bronchitis — an inflammation of the tubes that carry air to and from the lungs — and emphyma — a dia in which the lungs' many air sacs are destroyed, leaving patients short of breath. So far there are not enough data to say with certainty whether e-cigs worn the disorders.
The few scientists actively trying to fill the gap in the rearch literature are running into obstacles. When studying tobacco cigarettes, rearchers rely on smoking machines that simulate how frequently a typical smoker takes a puff and how much smoke is inhaled with each breath. No one has yet determined how much e-cig vapor the typical ur breathes in, so different studies assume different amounts of vapor as their standard, making it difficult to compare their results. Tracing what happens to that vapor once it is inhaled is equally problematic. When the human body breaks down a foreign substance, one can typically find chemical by-products in hair or urine that provide clues about how it has interacted with cells. This is true for nicotine, but in the ca of propylene glycol, no one has established what the relevant by-product is or how to best detect it.
Wild West
奥斯卡奖电影As scientists struggle to test the safety of e-cigarettes, the devices are becoming more and more popular among teens and preteens. E-cigarette u among U.S. high school students more than doubled from 4.7 percent in 2011 to 10 percent in 2012, according to
recent data from the Centers for Dia Control and Prevention's National Youth Tobacco Survey. At least 160,000 students who had never tried conventional cigarettes puffed on e-cigs. Yet another analysis linked
我想你了英文romee-cig u with greater odds of trying tobacco. They come in kid-friendly flavors, including chocolate, bubble gum and gummy bear.Sold online and in the mall, e-cigarettes are also easy for minors to Acquire.
冰河世纪3迅雷下载 Federal legislative milestones that protect youngsters from conventional cigarettes — such as blocking sales to minors and preventing commercials targeted at adolescents — do not exist for e-cigarettes. In an attempt to remedy the situation, 40 state attorneys genera] signed a letter last September urging the FDA to assume "immediate regulatory oversight of e-cigarettes, an increasingly widespread, addictive product.
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