‘Non-Smoking’ Doesn’t Mean Smoke-Free“禁烟”不等于“无烟”

Despite decades of indoor smoking bans and restrictions， new research from Drexel University suggests the toxins we’ve been trying to keep out are still finding their way into the air inside. Findings by a group of environmental engineers show that third-hand smoke， the chemical residue from cigarette smoke that attaches to anything and anyone in the vicinity of a smoke cloud， can make its way into the air and circulate through buildings where no one is smoking.

室内吸烟禁限令已实施数十年。不过，德雷塞尔大学的最新研究表明，虽然我们一直努力将烟草毒素拒之门外，但这些毒素仍然能够进入室内空气。环境工程师们的研究结果显示，三手烟能在无人吸烟的建筑内潜入空气，进行室内循环。三手烟是指附着在烟团附近任何人或物上面的烟草烟雾化学残留物。

The study， which was recently published in the journal Science Advances， further clarifies our understanding of just how pervasive the toxic chemicals of cigarette smoke can be—even in a “smoke-free” indoor environment.

该研究成果不久前发表于《科学进展》杂志，让人们进一步认清了烟草烟雾有毒化学物质的传播范围——即便是“无烟”的室内环境也无法幸免。

“While many public areas have restriction on smoking， including distance from doorways， non-smoking buildings and even full smoking bans on campus for some universities， these smoking limitations often only serve to protect non-smoking populations from exposure to second-hand smoke，” said Michael Waring， PhD， an associate professor in Drexel’s College of Engineering， and a co-author of the research. “This study shows that third-hand smoke， which we are realizing can be harmful to health as with second-hand smoke， is much more difficult to avoid.”

德雷塞尔大学工程学院副教授、该研究成果共同作者之一迈克尔·韦林博士表示：“虽然许多公共区域都有吸烟限制，比如吸烟区要与门口保持距离、楼内禁止吸烟、一些大学实行校园内全面禁烟，但这些限制往往只能保护非吸烟人群免受二手烟的危害。该研究显示，避开三手烟的难度要大得多，而我们逐渐意识到三手烟和二手烟一样对健康有害。”

Peter DeCarlo， PhD， an atmospheric chemist at Drexel， teamed up with Waring， whose research focuses on indoor air quality， on this National Science Foundation-funded work that revealed the new pathway of exposure to third-hand smoke.

德雷塞尔大学大气化学家彼得·德卡洛博士与专事室内空气质量研究的韦林博士携手，完成了这一由美国国家科学基金会资助的项目，揭开了此前未曾发现的三手烟接触途径。

“Aerosol particles are ubiquitous particles suspended in the air—they come from a variety of sources and are known to be detrimental to health，” DeCarlo said. “The fact that third-hand smoke can attach to them， like it would to the clothing or furniture of a smoker， means that the potentially toxic chemicals associated with third hand smoke are found in places we wouldn’t have expected.”

“气溶胶颗粒是悬浮于空气中的微粒，几乎无处不在。这些微粒来源广泛，据知对人体健康有害。”德卡洛博士解释道，“三手烟能附着在气溶胶颗粒上，正如它会吸附在吸烟者的衣物或家具上，这意味着与其相关的潜在有毒化学物质会出现在我们意想不到的任何地方。”

A surprise inside

室内的“意外发现”

Anita Avery， PhD， a doctoral student working with DeCarlo was studying the transport of particles from outdoors to indoors by monitoring these particles inside an unoccupied， non-smoking classroom. The composition of these particles， measured by an aerosol mass spectrometer over the course of several weeks， provided a detailed look at the chemical differences between outdoor and indoor particles in the air.

安妮塔·埃弗里博士在德卡洛指导下攻读博士学位期间，曾通过监测一个闲置的无烟教室内的颗粒物状况，来研究颗粒物从室外到室内的传播。数周时间里，她借助气溶胶质谱仪对这些颗粒物的成分进行了检测，详细考察了室内外空气中颗粒物的化学差异。

What they found was eye-opening.

研究发现令人大开眼界。

“In an empty classroom， where smoking has not been allowed in some time， we found that 29 percent of the entire indoor aerosol mass contained third-hand smoke chemical species. This was obviously quite startling and raised many questions about how that much third-hand smoke could be lingering in a non-smoking， ventilated room，” Avery said.

埃弗里表示：“教室是空的，已经禁烟一段时间，但我们发现，29%的室内气溶胶含有三手烟化学物质。这着实令人震惊，引发了很多问题——在这样一个无烟且通风的房间里，三手烟为何难以绝迹？”

To investigate the cause of this surprising finding， Avery and DeCarlo simulated some third-hand smoke exposure in the lab. First， they pumped cigarette smoke into a Pyrex1 container， allowing the smoke chemicals to be deposited inside. Then they pumped any residual smoke out of the container before pulling outdoor air through it to clear out any second-hand smoke.

为了探究这一惊人发现的背后原因，埃弗里和德卡洛在实验室中模拟了若干种接触到三手烟的场景。首先，他们将烟草烟雾泵入一个派热克斯耐热玻璃容器，使烟雾中的化学物质沉积其中。随后，将容器中的所有残留烟雾抽出，再注入室外空气，以彻底清除残留的二手烟雾。

After a day， filtered outdoor air was circulated through the container and the researchers measured the chemical composition of the aerosol particles it acquired along the way and compared it to outdoor air that hadn’t passed through the container. They found a 13 percent increase in third-hand smoke chemical species in the air that went through the Pyrex container， which meant that， though it seemed as though the smoke had cleared， a chemical residue still existed—and found a way to attach to passing aerosol particles.

一天后，研究人员将过滤后的室外空气在容器中循环，检测此过程之后气溶胶颗粒的化学成分，并与未流经容器的室外空气进行比较分析。他们发现，流经玻璃容器的空气中三手烟化学物质增加了13%，这意味着，玻璃容器中的烟雾看似已经清除，实则仍有残留的化学物质，并且得以附着于从容器中通过的气溶胶颗粒。

“This means that our discovery was by no means unique to that classroom， in fact， it’s likely quite a widespread phenomenon，” DeCarlo said. “What we’d actually uncovered was a new exposure route for third-hand smoke—through aerosol particles， which are ubiquitous in the indoor environment.”

“这说明我们的研究发现绝非局限于那间教室，事实上，这可能是一种相当普遍的现象。”德卡洛博士说，“我们实际上发现了一种接触到三手烟的新途径，即通过室内环境中无处不在的气溶胶颗粒进行传播。”

Hitching a ride

搭便车

Previous research on third-hand smoke chemicals has shown that as they transition out of gas form， they can settle just about anywhere. They can attach to clothing and furniture， on skin or hair—even onto a sterile surface， such as the Pyrex container， as the Drexel researchers found. But they can concentrate in particles when the chemicals are in gas form and they are exposed to acidic， liquid aerosols.

前期研究表明，三手烟化学物质脱离气态以后，可以沉积于任何地方。它们可以附着在衣物、家具、皮肤或毛发上，甚至如德雷塞尔大学研究员发现的那样，可以附着于像派热克斯耐热玻璃容器这样的无菌表面。但当这些化学物质处于气态并接触到酸性液态气溶胶时，它们就可以在气溶胶颗粒中聚集。

This means that they can be unwittingly transported into smoke-free envir-onments—lying in wait for conditions that allow them to transition back into a gas and attach to aerosols.

这意味着化学物质可能在不知不觉中被传播至无烟环境中，等待时机变回气态附着于气溶胶之上。

But as it turns out， this combination of conditions is actually pretty common indoors. The study suggests that third-hand smoke chemicals on indoor surfaces can “repartition，” or return， to the gas phase when they’re exposed to chemicals such as ammonia—which is common in buildings as it’s emitted when people breathe and often found in bathrooms.

实际上，在室内环境中，上述条件很容易达成。该研究表明，附着于室内物体表面的三手烟化学物质接触到氨等化学物质时，会“重新分配”，即重返气态。氨气在建筑物内很常见，人呼吸时会释放氨气，卫生间也是氨气聚集地。

And the aqueous aerosols they need for transportation？

那么三手烟化学物质传播所需的液相气溶胶从何而来呢？

“In the summertime warm air with varying amounts of water content is brought into the building， mixed with recirculated air， and conditioned to cooler temperatures，” they write. “This process leads to significant uptake of water by aerosol particles. This continuous summertime presence of aerosol water allows third-hand smoke chemicals to partition2 into the aerosol phase.”

“夏季，水分含量不一的暖空气进入建筑物内部，与再循环空气混合并降温。”研究人员写道，“在这一过程中，气溶胶颗粒大量吸收水分。正是由于夏季持续存在气溶胶水，三手烟化学物质得以分离出来进入气溶胶颗粒。”

Indeed， the indoor environment of buildings with mechanical heating， ventilation and air conditioning （HVAC） can be the precise confluence of factors necessary to spread these toxic chemicals.

事实上，配备暖通空调系统（用于供暖、通风和空气调节）的室内环境，正好可以汇集传播这些有毒物质所需的各种条件。

“The HVAC system not only serves to condition the aerosols to wet or dry states， but also to move air through a building zone. HVAC systems recirculate and disperse air throughout the multiple rooms of the zone served by the system，” they write. “For this reason， a room located near a smoking area with smoke penetration or a room occupied by a smoker can effectively expose the other occupants served by the same HVAC system to third-hand smoke， even if they do not share space directly.”

研究人员写道：“暖通空调系统不仅调控着气溶胶的干湿状态，还能促使室内外空气流动。空气可以在使用该系统的众多房间之间再循环和扩散。因此，即便大家并未直接共享同一空间，建筑物内的不吸烟者也难逃三手烟影响，就因他们所待房间与临近吸烟区并有烟雾渗透的房间或吸烟者的房间共用暖通空调系统。”

Breathing easy？

易于吸入？

The researchers note that the persistence of the chemicals in the indoor environment is also linked to the amount of surface area in a particular room or building. This is because the third-hand smoke that isn’t inhaled can deposit just about anywhere—counters， wallcuuck2+pfbCXk3jcD8UTNA==s， furniture even embedding in carpet—and later return to the air when conditions are right.

研究人员指出，化学物质在室内环境中的滞留还与特定房间或建筑内的表面积大小密切相关。这是因为未被人吸入的三手烟几乎无孔不入，可以黏附在任何地方，比如柜台、墙壁、家具，甚至嵌入地毯，待条件适宜时再次释放到空气中。

“While most people expect that they’ll be exposed to car exhaust， or other chemicals in low concentrations when they’re outside—they tend to think that they’re escaping all that when they step indoors，” DeCarlo said. “Understanding that we are constantly exposed to these chemicals， even in our workplaces， is a challenge to communicate to the general population.”

德卡洛说道：“大多数人能预料在室外会接触到汽车尾气或其他低浓度化学物质，倾向于相信只要进入室内就能避开它们。但现实情况是，即便是在室内工作场所中，我们也会不断接触到各类化学物质。让公众了解这一事实是一项挑战。”

（译者单位：中央民族大学外国语学院）

1 Pyrex派热克斯玻璃是抗热性能极佳的一种玻璃，被广泛应用于厨房用品、化学实验室仪器及光学设备等，它已成为其原材料硼化玻璃的通用性商标。

2 partition分隔，隔开。