Cigarettes aren't just toxic¹ when they're being smoked. Even when the butts³ are scrunched⁴ up and cold, new research has found they continue to emit harmful compounds in the air.

香烟不仅在燃烧时有毒，甚至在烟蒂被揉成一团，彻底熄灭以后，一项新研究发现它们继续向空气中释放有害化合物。

In the first 24 hours alone, scientists say a used cigarette butt² will produce 14 percent of the nicotine⁵ that an actively⁶ burning cigarette would. And the airborne emissions⁷ don't stop there.

科学家说仅在前24小时内，吸过的烟蒂释放的尼古丁是燃烧时的14%，并且还在继续向空气中释放物质。

While most of these chemicals are released within a day of being extinguished, an analysis for the United States Food and Drug Administration (FDA) found concentrations of nicotine and triacetin - a plasticiser in cigarette filters - had fallen by just half a whopping five days later.

虽然在熄灭以后的一天内会释放掉大多数化学物质，但食品及药物管理局的一项分析发现尼古丁和三乙胺（香烟过滤器中的塑化剂）的浓度在五天以后仅下降一半。

"I was absolutely surprised," says environmental engineer Dustin Poppendieck from the United States National Institute of Standards and Technology (NIST).

美国国家标准与技术研究院环境工程师Dustin Poppendieck说：“我非常惊讶。”

"The numbers are significant and could have important impacts when butts are disposed of indoors or in cars."

“这些数值很重要，烟蒂被扔在室内或车里时这些数值很值得关注。”

While much attention has been paid to the health impacts of first-hand, second-hand⁸ and now third-hand smoking - where chemical residues⁹ linger on walls and furniture - the actual butt of the matter has been paid little attention.

人们关注的都是一手烟、二手烟和现在的三手烟对健康的影响，三手烟是指化学物质残留在墙和家具上，但这一问题的关键却没有受到太多关注。

To measure airborne emissions from this forgotten remnant, Poppendieck and his team placed 2,100 recently extinguished cigarettes inside a walk-in chamber¹⁰ made of stainless¹¹ steel.

为了检测被遗忘的烟头释放到空气中的物质，Poppendieck和他的团队在一个不锈钢步入式恒温恒湿试验室内放了2,100个刚熄灭的香烟。

Once the freshly-extinguished ends were sealed away, the team measured eight chemicals commonly emitted by cigarettes, four of which the FDA have their eye on for being harmful or potentially so.

刚熄灭的烟头刚被密封，研究团队就开始检测常见的香烟释放的8种化学物质，其中4种因为有害或有潜在危害而受到食品及药物管理局关注。

Triacetin is not one of the dangerous ones, but because it's so common in cigarette filters and doesn't evaporate easily, it's a good indicator¹² of how other sticky chemicals are breaking down.

三醋精不是危险物质，但因为在香烟过滤器中很常见，而且不易挥发，所以能很好的显示其他粘性物质是如何分解的。

Fiddling¹³ with the room's temperature, humidity and saturation¹⁴, the authors tested how emissions changed under certain conditions. When the air temperature of the room was higher, for instance, they noticed the butts emitted these chemicals at higher rates.

研究者们先设定好房间的温度、湿度和饱和度，然后测试在特定条件下排放量的变化。比如提高房间温度时，他们注意到烟蒂释放这些化学物质的速度更快。

In other words, leaving ashtrays¹⁵ out for days at a time, especially in the heat seems like a bad idea, and could potentially expose smokers¹⁶ and nonsmokers to even more harmful chemicals than we thought.

换句话说，连续几天不清理烟灰缸不是好习惯，尤其是在温度高的时候，吸烟者和非吸烟者接触到的有害化学物质比我们想象的要多。