Pig-Pen effect: Mixing skin oil and ozone can produce a personal pollution cloud

猪圈效应：皮肤油脂和臭氧混合会造成个人污染气体

上海译锐翻译  2019-7-3     13:35 p.m.

When ozone and skin oils meet, the resulting reaction may help remove ozone from an indoor environment, but it can also produce a personal cloud of pollutants that affects indoor air quality, according to a team of researchers.

根据研究团队的介绍，当臭氧和皮肤油脂相遇，所发生的反应可能有助于减少室内的臭氧。但同时，其也会产生影响室内空气质量的个人污染物。

In a computer model of indoor environments, the researchers show that a range of volatile and semi-volatile gases and substances are produced when ozone, a form of oxygen that can be toxic, reacts with skin oils carried by soiled clothes, a reaction that some researchers have likened to the less-than-tidy Peanuts comic strip character.

在一个计算机室内环境模型中，研究人员发现，臭氧（一种可能具有毒性的氧气）和脏衣服中所含的皮肤油脂发生反应时会产生一系列挥发性和半挥发性的气体和物质。某些研究人员将一种反应比喻为连环漫画《花生漫画》中那些邋遢的动画人物。

"When the ozone is depleted through human skin, we become the generator of the primary products, which can cause sensory irritations," said Donghyun Rim, assistant professor of architectural engineering and an Institute for CyberScience associate, Penn State. "Some people call this higher concentration of pollutants around the human body the personal cloud, or we call it the 'Pig-Pen Effect.'"

宾州州立大学建筑工程助教兼网络科学研究所助教Donghyun Rim表示：“当臭氧在人体皮肤中被消耗掉后，我们就成为主要产物的产生者，而这会造成感官刺激。一些人把人体周围这种高浓度的污染物称为个人气体，我们称之为‘猪圈效应’。”

The substances that are produced by the reaction include organic compounds, such as carbonyls, that can irritate the skin and lungs, said Rim. People with asthma may be particularly vulnerable to ozone and ozone reaction products, he said.

反应所产生的物质包括有机化合物，比如会对皮肤和肺部造成刺激的羰基。哮喘人群也许特别容易受到臭氧以及臭氧反应物质的影响。

According to the researchers, who reported their findings in a recent issue of Nature's Communications Chemistry, skin oils contain substances, such as squalene, fatty acids and wax esters. If a person wears the same clothes too long -- for example, more than a day -- without washing, there is a chance that the clothes become more saturated with the oils, leading to a higher chance of reaction with ozone, which is an unstable gas.

研究人员在最近一期的《自然通信化学》杂志中发表了他们的研究结果。据研究人员介绍，皮肤油脂中含有鲨烯、脂肪酸和蜡酯等物质。如果一个人超过一天不换衣服，那么这件衣服就会沾有大量皮肤油脂并增加和臭氧--一种不稳定气体发生反应的概率。

"Squalene can react very effectively with ozone," said Rim. "Squalene has a higher reaction rate with ozone because it has a double carbon bond and, because of its chemical makeup, the ozone wants to jump in and break this bond."

Rim表示：“鲨烯可以以非常有效的方式与臭氧发生反应。鲨烯与臭氧具有更高的反应率，这主要是因为鲨烯具有碳双键。正是由于这种化学组成，臭氧会跳入并打破链接。”

Indoors, ozone concentration can range from 5 to 25 parts per billion -- ppb -- depending on how the air is circulating from outside to inside and what types of chemicals and surfaces are used in the building. In a polluted city, for example, the amount of ozone in indoor environments may be much higher.

在室内，臭氧的浓度范围在5-25ppb之间，这具体取决于空气如何从外部流入室内以及建筑物中使用了哪种化学物质和表面材料。在污染的城市里，举个例子，室内环境下的臭氧含量也许更高。

"A lot of people think of the ozone layer when we talk about ozone," said Rim. "But, we're not talking about that ozone, that's good ozone. But ozone at the ground level has adverse health impacts."

Rim说：“许多人会在我们谈论臭氧时想到臭氧层。但是，我们所谈论的并非臭氧层，那是一种好的臭氧。地面上的臭氧层会对健康产生不利影响。”

Wearing clean clothes might be a good idea for a lot of reasons, but it might not necessarily lead to reducing exposure to ozone, said Rim. For example, a single soiled t-shirt helps keep ozone out of the breathing zone by removing about 30 to 70 percent of the ozone circulating near a person.

穿干净的衣服从许多角度来看也许是个不错的主意，但是干净衣服并非一定可以减少皮肤与臭氧的接触，Rim表示。比如说，一件脏T恤可以将围绕在一个人周围的臭氧减少大约30%到70%，并将臭氧排除在呼吸区域之外。

"If you have clean clothes, that means you might be breathing in more of this ozone, which isn't good for you either," said Rim.

Rim表示：“如果你穿干净的衣服，这意味着你可能会吸入更多的臭氧，而这同样对你不利。”

Rim said that the research is one part of a larger project to better understand the indoor environment where people spend most of their time.

Rim表示，这个项目是一个大项目的一部分，该项目旨在更好地了解人们大部分时间所处于的室内环境。

"The bottom line is that we, humans, spend more than 90 percent of our time in buildings, or indoor environments, but, as far as actual research goes, there are still a lot of unknowns about what's going on and what types of gases and particles we're exposed to in indoor environments," said Rim. "The things that we inhale, that we touch, that we interact with, many of those things are contributing to the chemical accumulations in our body and our health."

Rim表示：“我们人类90%以上的时间是在建筑物或室内环境中度过的，但是随着实际研究的展开，关于室内的情况以及我们在室内会接触哪类气体和粒子仍有许多未知状况。我们所吸入的、触摸到的以及接触到的许多东西都会造成化学物在我们体内堆积并会对我们的健康产生影响。”

Rather than advising people whether to wear clean or dirty clothes, the researchers suggest that people should focus on keeping ground ozone levels down. Better building design and filtration, along with cutting pollution, are ways that could cut the impact of the Pig-Pen Effect, they added.

研究人员并没有建议人们是穿干净的或是脏衣服，相反，研究人员建议人们应该把重点放在控制地面的臭氧水平。更佳的建筑设计和过滤以及减少污染都可以减少猪圈效应所带来的影响，他们补充说。

To build and validate the models, the researchers used experimental data from prior experiments investigating reactions between ozone and squalene, and between ozone and clothing. The researchers then analyzed further how the squalene-ozone reaction creates pollutants in various indoor conditions.

研究人员利用之前研究臭氧和鲨烯以及臭氧和服装之间反应的实验数据来建立并验证模型。随后，研究人员进一步分析了鲨烯和臭氧之间的反应是如何在各种室内环境下产生污染物的。

The team relied on computer modeling to simulate indoor spaces that vary with ventilation conditions and how inhabitants of those spaces manage air quality, Rim said.

团队依靠计算机建模来模拟具有不同通风的室内空间并模拟空间居住人员管理空气质量的方式，Rim表示。

In the future, the team may look at how other common indoor sources, such as candle and cigarette smoke, could affect the indoor air quality and its impact on human health.

在未来，团队可能会探索其他常见的室内气体来源，比如蜡烛和香烟是如何影响空气质量的，以及其对人类健康的影响。

文章来源：科学时报         编辑：质控部Susan